openstack-manuals/doc/arch-design/locale/arch-design.pot

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#: ./doc/arch-design/ch_introduction.xml:7(title)
msgid "Introduction"
msgstr ""

#: ./doc/arch-design/ch_introduction.xml:9(para)
msgid "<glossterm>OpenStack</glossterm> is a fully-featured, self-service cloud. This book takes you through some of the considerations you have to make when designing your cloud."
msgstr ""

#: ./doc/arch-design/ch_specialized.xml:7(title)
msgid "Specialized cases"
msgstr ""

#: ./doc/arch-design/ch_specialized.xml:8(para)
msgid "Although most OpenStack architecture designs fall into one of the seven major scenarios outlined in other sections (compute focused, network focused, storage focused, general purpose, multi-site, hybrid cloud, and massively scalable), there are a few use cases that do not fit into these categories. This section discusses these specialized cases and provide some additional details and design considerations for each use case:"
msgstr ""

#: ./doc/arch-design/ch_specialized.xml:18(para)
msgid "<link linkend=\"specialized-networking-example\">Specialized networking</link>: describes running networking-oriented software that may involve reading packets directly from the wire or participating in routing protocols."
msgstr ""

#: ./doc/arch-design/ch_specialized.xml:28(para)
msgid "<link linkend=\"software-defined-networking-sdn\">Software-defined networking (SDN)</link>: describes both running an SDN controller from within OpenStack as well as participating in a software-defined network."
msgstr ""

#: ./doc/arch-design/ch_specialized.xml:37(para)
msgid "<link linkend=\"desktop-as-a-service\">Desktop-as-a-Service</link>: describes running a virtualized desktop environment in a cloud (<glossterm>Desktop-as-a-Service</glossterm>). This applies to private and public clouds."
msgstr ""

#: ./doc/arch-design/ch_specialized.xml:46(para)
msgid "<link linkend=\"arch-guide-openstack-on-openstack\">OpenStack on OpenStack</link>: describes building a multi-tiered cloud by running OpenStack on top of an OpenStack installation."
msgstr ""

#: ./doc/arch-design/ch_specialized.xml:54(para)
msgid "<link linkend=\"specialized-hardware\">Specialized hardware</link>: describes the use of specialized hardware devices from within the OpenStack environment."
msgstr ""

#: ./doc/arch-design/ch_compute_focus.xml:7(title)
msgid "Compute focused"
msgstr ""

#: ./doc/arch-design/ch_compute_focus.xml:8(para)
msgid "Compute-focused clouds are a specialized subset of the general purpose OpenStack cloud architecture. A compute-focused cloud specifically supports compute intensive workloads."
msgstr ""

#: ./doc/arch-design/ch_compute_focus.xml:12(para)
msgid "Compute intensive workloads may be CPU intensive, RAM intensive, or both; they are not typically storage or network intensive."
msgstr ""

#: ./doc/arch-design/ch_compute_focus.xml:15(para)
msgid "Compute-focused workloads may include the following use cases:"
msgstr ""

#: ./doc/arch-design/ch_compute_focus.xml:18(para) ./doc/arch-design/ch_network_focus.xml:135(term)
msgid "High performance computing (HPC)"
msgstr ""

#: ./doc/arch-design/ch_compute_focus.xml:21(para)
msgid "Big data analytics using Hadoop or other distributed data stores"
msgstr ""

#: ./doc/arch-design/ch_compute_focus.xml:25(para)
msgid "Continuous integration/continuous deployment (CI/CD)"
msgstr ""

#: ./doc/arch-design/ch_compute_focus.xml:28(para)
msgid "Platform-as-a-Service (PaaS)"
msgstr ""

#: ./doc/arch-design/ch_compute_focus.xml:31(para)
msgid "Signal processing for network function virtualization (NFV)"
msgstr ""

#: ./doc/arch-design/ch_compute_focus.xml:35(para)
msgid "A compute-focused OpenStack cloud does not typically use raw block storage services as it does not host applications that require persistent block storage."
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:8(title)
msgid "Security and legal requirements"
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:9(para)
msgid "This chapter discusses the legal and security requirements you need to consider for the different OpenStack scenarios."
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:12(title)
msgid "Legal requirements"
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:13(para)
msgid "Many jurisdictions have legislative and regulatory requirements governing the storage and management of data in cloud environments. Common areas of regulation include:"
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:18(para)
msgid "Data retention policies ensuring storage of persistent data and records management to meet data archival requirements."
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:23(para)
msgid "Data ownership policies governing the possession and responsibility for data."
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:27(para)
msgid "Data sovereignty policies governing the storage of data in foreign countries or otherwise separate jurisdictions."
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:32(para)
msgid "Data compliance policies governing certain types of information needing to reside in certain locations due to regulatory issues - and more importantly, cannot reside in other locations for the same reason."
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:38(para)
msgid "Examples of such legal frameworks include the <link xlink:href=\"http://ec.europa.eu/justice/data-protection/\">data protection framework</link> of the European Union and the requirements of the <link xlink:href=\"http://www.finra.org/Industry/Regulation/FINRARules/\"> Financial Industry Regulatory Authority</link> in the United States. Consult a local regulatory body for more information."
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:48(title) ./doc/arch-design/storage_focus/section_tech_considerations_storage_focus.xml:47(term) ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:422(term) ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:154(para) ./doc/arch-design/hybrid/section_architecture_hybrid.xml:112(para) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:581(term) ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:649(title) ./doc/arch-design/generalpurpose/section_user_requirements_general_purpose.xml:143(term)
msgid "Security"
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:49(para)
msgid "When deploying OpenStack in an enterprise as a private cloud, despite activating a firewall and binding employees with security agreements, cloud architecture should not make assumptions about safety and protection. In addition to considering the users, operators, or administrators who will use the environment, consider also negative or hostile users who would attack or compromise the security of your deployment regardless of firewalls or security agreements."
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:57(para)
msgid "Attack vectors increase further in a public facing OpenStack deployment. For example, the API endpoints and the software behind it become vulnerable to hostile entities attempting to gain unauthorized access or prevent access to services. This can result in loss of reputation and you must protect against it through auditing and appropriate filtering."
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:64(para)
msgid "It is important to understand that user authentication requests encase sensitive information such as user names, passwords, and authentication tokens. For this reason, place the API services behind hardware that performs SSL termination."
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:69(para)
msgid "Be mindful of consistency when utilizing third party clouds to explore authentication options."
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:74(title)
msgid "Security domains"
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:75(para)
msgid "A security domain comprises users, applications, servers or networks that share common trust requirements and expectations within a system. Typically, security domains have the same authentication and authorization requirements and users."
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:79(para)
msgid "You can map security domains individually to the installation, or combine them. For example, some deployment topologies combine both guest and data domains onto one physical network. In other cases these networks are physically separate. Map out the security domains against specific OpenStack topologies needs. The domains and their trust requirements depend on whether the cloud instance is public, private, or hybrid."
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:88(title)
msgid "Public security domains"
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:89(para)
msgid "The public security domain is an untrusted area of the cloud infrastructure. It can refer to the internet as a whole or simply to networks over which the user has no authority. Always consider this domain untrusted. For example, in a hybrid cloud deployment, any information traversing between and beyond the clouds is in the public domain and untrustworthy."
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:98(title)
msgid "Guest security domains"
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:99(para)
msgid "Typically used for compute instance-to-instance traffic, the guest security domain handles compute data generated by instances on the cloud but not services that support the operation of the cloud, such as API calls. Public cloud providers and private cloud providers who do not have stringent controls on instance use or who allow unrestricted internet access to instances should consider this domain to be untrusted. Private cloud providers may want to consider this network as internal and therefore trusted only if they have controls in place to assert that they trust instances and all their tenants."
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:112(title)
msgid "Management security domains"
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:113(para)
msgid "The management security domain is where services interact. The networks in this domain transport confidential data such as configuration parameters, user names, and passwords. Trust this domain when it is behind an organization's firewall in deployments."
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:119(title)
msgid "Data security domains"
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:120(para)
msgid "The data security domain is concerned primarily with information pertaining to the storage services within OpenStack. The data that crosses this network has integrity and confidentiality requirements. Depending on the type of deployment there may also be availability requirements. The trust level of this network is heavily dependent on deployment decisions and does not have a default level of trust."
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:130(title)
msgid "Hypervisor-security"
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:131(para)
msgid "The hypervisor also requires a security assessment. In a public cloud, organizations typically do not have control over the choice of hypervisor. Properly securing your hypervisor is important. Attacks made upon the unsecured hypervisor are called a <firstterm>hypervisor breakout</firstterm>. Hypervisor breakout describes the event of a compromised or malicious instance breaking out of the resource controls of the hypervisor and gaining access to the bare metal operating system and hardware resources."
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:141(para)
msgid "There is not an issue if the security of instances is not important. However, enterprises need to avoid vulnerability. The only way to do this is to avoid the situation where the instances are running on a public cloud. That does not mean that there is a need to own all of the infrastructure on which an OpenStack installation operates; it suggests avoiding situations in which sharing hardware with others occurs."
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:150(title)
msgid "Baremetal security"
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:151(para)
msgid "There are other services worth considering that provide a bare metal instance instead of a cloud. In other cases, it is possible to replicate a second private cloud by integrating with a private Cloud-as-a-Service deployment. The organization does not buy the hardware, but also does not share with other tenants. It is also possible to use a provider that hosts a bare-metal public cloud instance for which the hardware is dedicated only to one customer, or a provider that offers private Cloud-as-a-Service."
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:161(para)
msgid "Each cloud implements services differently. What keeps data secure in one cloud may not do the same in another. Be sure to know the security requirements of every cloud that handles the organization's data or workloads."
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:167(para)
msgid "More information on OpenStack Security can be found in the <link xlink:href=\"http://docs.openstack.org/security-guide\"><citetitle>OpenStack Security Guide</citetitle></link>."
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:172(title)
msgid "Networking Security"
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:173(para)
msgid "Consider security implications and requirements before designing the physical and logical network topologies. Make sure that the networks are properly segregated and traffic flows are going to the correct destinations without crossing through locations that are undesirable. Consider the following example factors:"
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:180(para) ./doc/arch-design/ch_generalpurpose.xml:72(para)
msgid "Firewalls"
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:183(para)
msgid "Overlay interconnects for joining separated tenant networks"
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:186(para)
msgid "Routing through or avoiding specific networks"
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:189(para)
msgid "How networks attach to hypervisors can expose security vulnerabilities. To mitigate against exploiting hypervisor breakouts, separate networks from other systems and schedule instances for the network onto dedicated compute nodes. This prevents attackers from having access to the networks from a compromised instance."
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:196(title)
msgid "Multi-site security"
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:197(para)
msgid "Securing a multi-site OpenStack installation brings extra challenges. Tenants may expect a tenant-created network to be secure. In a multi-site installation the use of a non-private connection between sites may be required. This may mean that traffic would be visible to third parties and, in cases where an application requires security, this issue requires mitigation. In these instances, install a VPN or encrypted connection between sites to conceal sensitive traffic."
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:205(para)
msgid "Another security consideration with regard to multi-site deployments is Identity. Centralize authentication within a multi-site deployment. Centralization provides a single authentication point for users across the deployment, as well as a single point of administration for traditional create, read, update, and delete operations. Centralized authentication is also useful for auditing purposes because all authentication tokens originate from the same source."
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:214(para)
msgid "Just as tenants in a single-site deployment need isolation from each other, so do tenants in multi-site installations. The extra challenges in multi-site designs revolve around ensuring that tenant networks function across regions. OpenStack Networking (neutron) does not presently support a mechanism to provide this functionality, therefore an external system may be necessary to manage these mappings. Tenant networks may contain sensitive information requiring that this mapping be accurate and consistent to ensure that a tenant in one site does not connect to a different tenant in another site."
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:227(title) ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:353(para) ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:460(title) ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:219(title) ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:166(title) ./doc/arch-design/multi_site/section_tech_considerations_multi_site.xml:144(title) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:512(para) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:617(title) ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:412(title)
msgid "OpenStack components"
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:228(para)
msgid "Most OpenStack installations require a bare minimum set of pieces to function. These include OpenStack Identity (keystone) for authentication, OpenStack Compute (nova) for compute, OpenStack Image service (glance) for image storage, OpenStack Networking (neutron) for networking, and potentially an object store in the form of OpenStack Object Storage (swift). Bringing multi-site into play also demands extra components in order to coordinate between regions. Centralized Identity service is necessary to provide the single authentication point. Centralized dashboard is also recommended to provide a single login point and a mapped experience to the API and CLI options available. If needed, use a centralized Object Storage service, installing the required swift proxy service alongside the Object Storage service."
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:242(para)
msgid "It may also be helpful to install a few extra options in order to facilitate certain use cases. For instance, installing DNS service may assist in automatically generating DNS domains for each region with an automatically-populated zone full of resource records for each instance. This facilitates using DNS as a mechanism for determining which region would be selected for certain applications."
msgstr ""

#: ./doc/arch-design/ch_legal-security-requirements.xml:249(para)
msgid "Another useful tool for managing a multi-site installation is Orchestration (heat). The Orchestration service allows the use of templates to define a set of instances to be launched together or for scaling existing sets. It can set up matching or differentiated groupings based on regions. For instance, if an application requires an equally balanced number of nodes across sites, the same heat template can be used to cover each site with small alterations to only the region name."
msgstr ""

#: ./doc/arch-design/ch_network_focus.xml:7(title)
msgid "Network focused"
msgstr ""

#: ./doc/arch-design/ch_network_focus.xml:8(para)
msgid "All OpenStack deployments depend on network communication in order to function properly due to its service-based nature. In some cases, however, the network elevates beyond simple infrastructure. This chapter discusses architectures that are more reliant or focused on network services. These architectures depend on the network infrastructure and require network services that perform reliably in order to satisfy user and application requirements."
msgstr ""

#: ./doc/arch-design/ch_network_focus.xml:16(para)
msgid "Some possible use cases include:"
msgstr ""

#: ./doc/arch-design/ch_network_focus.xml:19(term)
msgid "Content delivery network"
msgstr ""

#: ./doc/arch-design/ch_network_focus.xml:21(para)
msgid "This includes streaming video, viewing photographs, or accessing any other cloud-based data repository distributed to a large number of end users. Network configuration affects latency, bandwidth, and the distribution of instances. Therefore, it impacts video streaming. Not all video streaming is consumer-focused. For example, multicast videos (used for media, press conferences, corporate presentations, and web conferencing services) can also use a content delivery network. The location of the video repository and its relationship to end users affects content delivery. Network throughput of the back-end systems, as well as the WAN architecture and the cache methodology, also affect performance."
msgstr ""

#: ./doc/arch-design/ch_network_focus.xml:36(term)
msgid "Network management functions"
msgstr ""

#: ./doc/arch-design/ch_network_focus.xml:38(para)
msgid "Use this cloud to provide network service functions built to support the delivery of back-end network services such as DNS, NTP, or SNMP."
msgstr ""

#: ./doc/arch-design/ch_network_focus.xml:44(term)
msgid "Network service offerings"
msgstr ""

#: ./doc/arch-design/ch_network_focus.xml:46(para)
msgid "Use this cloud to run customer-facing network tools to support services. Examples include VPNs, MPLS private networks, and GRE tunnels."
msgstr ""

#: ./doc/arch-design/ch_network_focus.xml:52(term)
msgid "Web portals or web services"
msgstr ""

#: ./doc/arch-design/ch_network_focus.xml:54(para)
msgid "Web servers are a common application for cloud services, and we recommend an understanding of their network requirements. The network requires scaling out to meet user demand and deliver web pages with a minimum latency. Depending on the details of the portal architecture, consider the internal east-west and north-south network bandwidth."
msgstr ""

#: ./doc/arch-design/ch_network_focus.xml:63(term)
msgid "High speed and high volume transactional systems"
msgstr ""

#: ./doc/arch-design/ch_network_focus.xml:65(para)
msgid "These types of applications are sensitive to network configurations. Examples include financial systems, credit card transaction applications, and trading and other extremely high volume systems. These systems are sensitive to network jitter and latency. They must balance a high volume of East-West and North-South network traffic to maximize efficiency of the data delivery. Many of these systems must access large, high performance database back ends."
msgstr ""

#: ./doc/arch-design/ch_network_focus.xml:78(term) ./doc/arch-design/multi_site/section_user_requirements_multi_site.xml:48(title) ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:132(term)
msgid "High availability"
msgstr ""

#: ./doc/arch-design/ch_network_focus.xml:80(para)
msgid "These types of use cases are dependent on the proper sizing of the network to maintain replication of data between sites for high availability. If one site becomes unavailable, the extra sites can serve the displaced load until the original site returns to service. It is important to size network capacity to handle the desired loads."
msgstr ""

#: ./doc/arch-design/ch_network_focus.xml:89(term)
msgid "Big data"
msgstr ""

#: ./doc/arch-design/ch_network_focus.xml:91(para)
msgid "Clouds used for the management and collection of big data (data ingest) have a significant demand on network resources. Big data often uses partial replicas of the data to maintain integrity over large distributed clouds. Other big data applications that require a large amount of network resources are Hadoop, Cassandra, NuoDB, Riak, and other NoSQL and distributed databases."
msgstr ""

#: ./doc/arch-design/ch_network_focus.xml:101(term)
msgid "Virtual desktop infrastructure (VDI)"
msgstr ""

#: ./doc/arch-design/ch_network_focus.xml:103(para)
msgid "This use case is sensitive to network congestion, latency, jitter, and other network characteristics. Like video streaming, the user experience is important. However, unlike video streaming, caching is not an option to offset the network issues. VDI requires both upstream and downstream traffic and cannot rely on caching for the delivery of the application to the end user."
msgstr ""

#: ./doc/arch-design/ch_network_focus.xml:112(term)
msgid "Voice over IP (VoIP)"
msgstr ""

#: ./doc/arch-design/ch_network_focus.xml:114(para)
msgid "This is sensitive to network congestion, latency, jitter, and other network characteristics. VoIP has a symmetrical traffic pattern and it requires network quality of service (QoS) for best performance. In addition, you can implement active queue management to deliver voice and multimedia content. Users are sensitive to latency and jitter fluctuations and can detect them at very low levels."
msgstr ""

#: ./doc/arch-design/ch_network_focus.xml:124(term)
msgid "Video Conference or web conference"
msgstr ""

#: ./doc/arch-design/ch_network_focus.xml:126(para)
msgid "This is sensitive to network congestion, latency, jitter, and other network characteristics. Video Conferencing has a symmetrical traffic pattern, but unless the network is on an MPLS private network, it cannot use network quality of service (QoS) to improve performance. Similar to VoIP, users are sensitive to network performance issues even at low levels."
msgstr ""

#: ./doc/arch-design/ch_network_focus.xml:137(para)
msgid "This is a complex use case that requires careful consideration of the traffic flows and usage patterns to address the needs of cloud clusters. It has high east-west traffic patterns for distributed computing, but there can be substantial north-south traffic depending on the specific application."
msgstr ""

#: ./doc/arch-design/ch_storage_focus.xml:7(title)
msgid "Storage focused"
msgstr ""

#: ./doc/arch-design/ch_storage_focus.xml:9(para)
msgid "Cloud storage is a model of data storage that stores digital data in logical pools and physical storage that spans across multiple servers and locations. Cloud storage commonly refers to a hosted object storage service, however the term also includes other types of data storage that are available as a service, for example block storage."
msgstr ""

#: ./doc/arch-design/ch_storage_focus.xml:15(para)
msgid "Cloud storage runs on virtualized infrastructure and resembles broader cloud computing in terms of accessible interfaces, elasticity, scalability, multi-tenancy, and metered resources. You can use cloud storage services from an off-premises service or deploy on-premises."
msgstr ""

#: ./doc/arch-design/ch_storage_focus.xml:20(para)
msgid "Cloud storage consists of many distributed, synonymous resources, which are often referred to as integrated storage clouds. Cloud storage is highly fault tolerant through redundancy and the distribution of data. It is highly durable through the creation of versioned copies, and can be consistent with regard to data replicas."
msgstr ""

#: ./doc/arch-design/ch_storage_focus.xml:26(para)
msgid "At large scale, management of data operations is a resource intensive process for an organization. Hierarchical storage management (HSM) systems and data grids help annotate and report a baseline data valuation to make intelligent decisions and automate data decisions. HSM enables automated tiering and movement, as well as orchestration of data operations. A data grid is an architecture, or set of services evolving technology, that brings together sets of services enabling users to manage large data sets."
msgstr ""

#: ./doc/arch-design/ch_storage_focus.xml:35(para)
msgid "Example applications deployed with cloud storage characteristics:"
msgstr ""

#: ./doc/arch-design/ch_storage_focus.xml:39(para)
msgid "Active archive, backups and hierarchical storage management."
msgstr ""

#: ./doc/arch-design/ch_storage_focus.xml:43(para)
msgid "General content storage and synchronization. An example of this is private dropbox."
msgstr ""

#: ./doc/arch-design/ch_storage_focus.xml:47(para)
msgid "Data analytics with parallel file systems."
msgstr ""

#: ./doc/arch-design/ch_storage_focus.xml:50(para)
msgid "Unstructured data store for services. For example, social media back-end storage."
msgstr ""

#: ./doc/arch-design/ch_storage_focus.xml:54(para)
msgid "Persistent block storage."
msgstr ""

#: ./doc/arch-design/ch_storage_focus.xml:57(para)
msgid "Operating system and application image store."
msgstr ""

#: ./doc/arch-design/ch_storage_focus.xml:60(para)
msgid "Media streaming."
msgstr ""

#: ./doc/arch-design/ch_storage_focus.xml:63(para)
msgid "Databases."
msgstr ""

#: ./doc/arch-design/ch_storage_focus.xml:66(para)
msgid "Content distribution."
msgstr ""

#: ./doc/arch-design/ch_storage_focus.xml:69(para)
msgid "Cloud storage peering."
msgstr ""

#: ./doc/arch-design/ch_generalpurpose.xml:7(title)
msgid "General purpose"
msgstr ""

#: ./doc/arch-design/ch_generalpurpose.xml:8(para)
msgid "An OpenStack general purpose cloud is often considered a starting point for building a cloud deployment. They are designed to balance the components and do not emphasize any particular aspect of the overall computing environment. Cloud design must give equal weight to the compute, network, and storage components. General purpose clouds are found in private, public, and hybrid environments, lending themselves to many different use cases."
msgstr ""

#: ./doc/arch-design/ch_generalpurpose.xml:18(para)
msgid "General purpose clouds are homogeneous deployments. They are not suited to specialized environments or edge case situations."
msgstr ""

#: ./doc/arch-design/ch_generalpurpose.xml:23(para)
msgid "Common uses of a general purpose cloud include:"
msgstr ""

#: ./doc/arch-design/ch_generalpurpose.xml:28(para)
msgid "Providing a simple database"
msgstr ""

#: ./doc/arch-design/ch_generalpurpose.xml:33(para)
msgid "A web application runtime environment"
msgstr ""

#: ./doc/arch-design/ch_generalpurpose.xml:38(para)
msgid "A shared application development platform"
msgstr ""

#: ./doc/arch-design/ch_generalpurpose.xml:43(para)
msgid "Lab test bed"
msgstr ""

#: ./doc/arch-design/ch_generalpurpose.xml:48(para)
msgid "Use cases that benefit from scale-out rather than scale-up approaches are good candidates for general purpose cloud architecture."
msgstr ""

#: ./doc/arch-design/ch_generalpurpose.xml:51(para)
msgid "A general purpose cloud is designed to have a range of potential uses or functions; not specialized for specific use cases. General purpose architecture is designed to address 80% of potential use cases available. The infrastructure, in itself, is a specific use case, enabling it to be used as a base model for the design process. General purpose clouds are designed to be platforms that are suited for general purpose applications."
msgstr ""

#: ./doc/arch-design/ch_generalpurpose.xml:58(para)
msgid "General purpose clouds are limited to the most basic components, but they can include additional resources such as:"
msgstr ""

#: ./doc/arch-design/ch_generalpurpose.xml:63(para) ./doc/arch-design/ch_massively_scalable.xml:36(para)
msgid "Virtual-machine disk image library"
msgstr ""

#: ./doc/arch-design/ch_generalpurpose.xml:66(para) ./doc/arch-design/ch_massively_scalable.xml:39(para)
msgid "Raw block storage"
msgstr ""

#: ./doc/arch-design/ch_generalpurpose.xml:69(para) ./doc/arch-design/ch_massively_scalable.xml:42(para)
msgid "File or object storage"
msgstr ""

#: ./doc/arch-design/ch_generalpurpose.xml:75(para)
msgid "Load balancers"
msgstr ""

#: ./doc/arch-design/ch_generalpurpose.xml:78(para)
msgid "IP addresses"
msgstr ""

#: ./doc/arch-design/ch_generalpurpose.xml:81(para)
msgid "Network overlays or virtual local area networks (VLANs)"
msgstr ""

#: ./doc/arch-design/ch_generalpurpose.xml:85(para) ./doc/arch-design/ch_massively_scalable.xml:58(para)
msgid "Software bundles"
msgstr ""

#: ./doc/arch-design/bk-openstack-arch-design.xml:7(title)
msgid "OpenStack Architecture Design Guide"
msgstr ""

#: ./doc/arch-design/bk-openstack-arch-design.xml:9(titleabbrev)
msgid "Architecture Guide"
msgstr ""

#: ./doc/arch-design/bk-openstack-arch-design.xml:17(orgname) ./doc/arch-design/bk-openstack-arch-design.xml:23(holder)
msgid "OpenStack Foundation"
msgstr ""

#: ./doc/arch-design/bk-openstack-arch-design.xml:21(year)
msgid "2014"
msgstr ""

#: ./doc/arch-design/bk-openstack-arch-design.xml:22(year)
msgid "2015"
msgstr ""

#: ./doc/arch-design/bk-openstack-arch-design.xml:25(releaseinfo)
msgid "current"
msgstr ""

#: ./doc/arch-design/bk-openstack-arch-design.xml:26(productname)
msgid "OpenStack"
msgstr ""

#: ./doc/arch-design/bk-openstack-arch-design.xml:30(remark)
msgid "Copyright details are filled in by the template."
msgstr ""

#: ./doc/arch-design/bk-openstack-arch-design.xml:36(remark)
msgid "Remaining licensing details are filled in by the template."
msgstr ""

#: ./doc/arch-design/bk-openstack-arch-design.xml:41(para)
msgid "To reap the benefits of OpenStack, you should plan, design, and architect your cloud properly, taking user's needs into account and understanding the use cases."
msgstr ""

#: ./doc/arch-design/ch_multi_site.xml:7(title)
msgid "Multi-site"
msgstr ""

#: ./doc/arch-design/ch_multi_site.xml:9(para)
msgid "OpenStack is capable of running in a multi-region configuration. This enables some parts of OpenStack to effectively manage a group of sites as a single cloud."
msgstr ""

#: ./doc/arch-design/ch_multi_site.xml:12(para)
msgid "Some use cases that might indicate a need for a multi-site deployment of OpenStack include:"
msgstr ""

#: ./doc/arch-design/ch_multi_site.xml:16(para)
msgid "An organization with a diverse geographic footprint."
msgstr ""

#: ./doc/arch-design/ch_multi_site.xml:20(para)
msgid "Geo-location sensitive data."
msgstr ""

#: ./doc/arch-design/ch_multi_site.xml:23(para)
msgid "Data locality, in which specific data or functionality should be close to users."
msgstr ""

#: ./doc/arch-design/ch_hybrid.xml:7(title)
msgid "Hybrid"
msgstr ""

#: ./doc/arch-design/ch_hybrid.xml:8(para)
msgid "A <glossterm baseform=\"hybrid cloud\">hybrid cloud</glossterm> design is one that uses more than one cloud. For example, designs that use both an OpenStack-based private cloud and an OpenStack-based public cloud, or that use an OpenStack cloud and a non-OpenStack cloud, are hybrid clouds."
msgstr ""

#: ./doc/arch-design/ch_hybrid.xml:13(para)
msgid "<glossterm baseform=\"bursting\">Bursting</glossterm> describes the practice of creating new instances in an external cloud to alleviate capacity issues in a private cloud."
msgstr ""

#: ./doc/arch-design/ch_hybrid.xml:17(title)
msgid "Example scenarios suited to hybrid clouds"
msgstr ""

#: ./doc/arch-design/ch_hybrid.xml:19(para)
msgid "Bursting from a private cloud to a public cloud"
msgstr ""

#: ./doc/arch-design/ch_hybrid.xml:23(para)
msgid "Disaster recovery"
msgstr ""

#: ./doc/arch-design/ch_hybrid.xml:26(para)
msgid "Development and testing"
msgstr ""

#: ./doc/arch-design/ch_hybrid.xml:29(para)
msgid "Federated cloud, enabling users to choose resources from multiple providers"
msgstr ""

#: ./doc/arch-design/ch_hybrid.xml:33(para)
msgid "Supporting legacy systems as they transition to the cloud"
msgstr ""

#: ./doc/arch-design/ch_hybrid.xml:37(para)
msgid "Hybrid clouds interact with systems that are outside the control of the private cloud administrator, and require careful architecture to prevent conflicts with hardware, software, and APIs under external control."
msgstr ""

#: ./doc/arch-design/ch_hybrid.xml:41(para)
msgid "The degree to which the architecture is OpenStack-based affects your ability to accomplish tasks with native OpenStack tools. By definition, this is a situation in which no single cloud can provide all of the necessary functionality. In order to manage the entire system, we recommend using a cloud management platform (CMP)."
msgstr ""

#: ./doc/arch-design/ch_hybrid.xml:47(para)
msgid "There are several commercial and open source CMPs available, but there is no single CMP that can address all needs in all scenarios, and sometimes a manually-built solution is the best option. This chapter includes discussion of using CMPs for managing a hybrid cloud."
msgstr ""

#: ./doc/arch-design/ch_massively_scalable.xml:7(title)
msgid "Massively scalable"
msgstr ""

#: ./doc/arch-design/ch_massively_scalable.xml:9(para)
msgid "A massively scalable architecture is a cloud implementation that is either a very large deployment, such as a commercial service provider might build, or one that has the capability to support user requests for large amounts of cloud resources."
msgstr ""

#: ./doc/arch-design/ch_massively_scalable.xml:14(para)
msgid "An example is an infrastructure in which requests to service 500 or more instances at a time is common. A massively scalable infrastructure fulfills such a request without exhausting the available cloud infrastructure resources. While the high capital cost of implementing such a cloud architecture means that it is currently in limited use, many organizations are planning for massive scalability in the future."
msgstr ""

#: ./doc/arch-design/ch_massively_scalable.xml:21(para)
msgid "A massively scalable OpenStack cloud design presents a unique set of challenges and considerations. For the most part it is similar to a general purpose cloud architecture, as it is built to address a non-specific range of potential use cases or functions. Typically, it is rare that particular workloads determine the design or configuration of massively scalable clouds. The massively scalable cloud is most often built as a platform for a variety of workloads. Because private organizations rarely require or have the resources for them, massively scalable OpenStack clouds are generally built as commercial, public cloud offerings."
msgstr ""

#: ./doc/arch-design/ch_massively_scalable.xml:32(para)
msgid "Services provided by a massively scalable OpenStack cloud include:"
msgstr ""

#: ./doc/arch-design/ch_massively_scalable.xml:45(para)
msgid "Firewall functionality"
msgstr ""

#: ./doc/arch-design/ch_massively_scalable.xml:48(para)
msgid "Load balancing functionality"
msgstr ""

#: ./doc/arch-design/ch_massively_scalable.xml:51(para)
msgid "Private (non-routable) and public (floating) IP addresses"
msgstr ""

#: ./doc/arch-design/ch_massively_scalable.xml:55(para)
msgid "Virtualized network topologies"
msgstr ""

#: ./doc/arch-design/ch_massively_scalable.xml:61(para)
msgid "Virtual compute resources"
msgstr ""

#: ./doc/arch-design/ch_massively_scalable.xml:64(para)
msgid "Like a general purpose cloud, the instances deployed in a massively scalable OpenStack cloud do not necessarily use any specific aspect of the cloud offering (compute, network, or storage). As the cloud grows in scale, the number of workloads can cause stress on all the cloud components. This adds further stresses to supporting infrastructure such as databases and message brokers. The architecture design for such a cloud must account for these performance pressures without negatively impacting user experience."
msgstr ""

#: ./doc/arch-design/ch_references.xml:8(title)
msgid "References"
msgstr ""

#: ./doc/arch-design/ch_references.xml:9(para)
msgid "<link xlink:href=\"http://ec.europa.eu/justice/data-protection/\">Data Protection framework of the European Union</link>: Guidance on Data Protection laws governed by the EU."
msgstr ""

#: ./doc/arch-design/ch_references.xml:15(para)
msgid "<link xlink:href=\"http://www.internetsociety.org/deploy360/blog/2014/05/goodbye-ipv4-iana-starts-allocating-final-address-blocks/\">Depletion of IPv4 Addresses</link>: describing how IPv4 addresses and the migration to IPv6 is inevitable."
msgstr ""

#: ./doc/arch-design/ch_references.xml:21(para)
msgid "<link xlink:href=\"http://www.garrettcom.com/techsupport/papers/ethernet_switch_reliability.pdf\">Ethernet Switch Reliability</link>: ​Research white paper on Ethernet Switch reliability."
msgstr ""

#: ./doc/arch-design/ch_references.xml:27(para)
msgid "<link xlink:href=\"http://www.finra.org/Industry/Regulation/FINRARules/\">Financial Industry Regulatory Authority</link>: ​Requirements of the Financial Industry Regulatory Authority in the USA."
msgstr ""

#: ./doc/arch-design/ch_references.xml:33(para)
msgid "<link xlink:href=\"http://docs.openstack.org/cli-reference/content/chapter_cli-glance-property.html\">Image Service property keys</link>: Glance API property keys allows the administrator to attach custom characteristics to images."
msgstr ""

#: ./doc/arch-design/ch_references.xml:39(para)
msgid "<link xlink:href=\"http://libguestfs.org\">LibGuestFS Documentation</link>: Official LibGuestFS documentation."
msgstr ""

#: ./doc/arch-design/ch_references.xml:43(para)
msgid "<link xlink:href=\"http://docs.openstack.org/openstack-ops/content/logging_monitoring.html\">Logging and Monitoring</link>: Official OpenStack Operations documentation."
msgstr ""

#: ./doc/arch-design/ch_references.xml:49(para)
msgid "<link xlink:href=\"http://manageiq.org/\">ManageIQ Cloud Management Platform</link>: An Open Source Cloud Management Platform for managing multiple clouds."
msgstr ""

#: ./doc/arch-design/ch_references.xml:54(para)
msgid "<link xlink:href=\"http://www.n-tron.com/pdf/network_availability.pdf\">N-Tron Network Availability</link>: Research white paper on network availability."
msgstr ""

#: ./doc/arch-design/ch_references.xml:60(para)
msgid "<link xlink:href=\"http://davejingtian.org/2014/03/30/nested-kvm-just-for-fun\">Nested KVM</link>: Post on how to nest KVM under KVM."
msgstr ""

#: ./doc/arch-design/ch_references.xml:65(para)
msgid "<link xlink:href=\"http://www.opencompute.org/\">Open Compute Project</link>: The Open Compute Project Foundation's mission is to design and enable the delivery of the most efficient server, storage and data center hardware designs for scalable computing."
msgstr ""

#: ./doc/arch-design/ch_references.xml:72(para)
msgid "<link xlink:href=\"http://docs.openstack.org/openstack-ops/content/flavors.html\">OpenStack Flavors</link>: Official OpenStack documentation."
msgstr ""

#: ./doc/arch-design/ch_references.xml:77(para)
msgid "<link xlink:href=\"http://docs.openstack.org/ha-guide/\">OpenStack High Availability Guide</link>: Information on how to provide redundancy for the OpenStack components."
msgstr ""

#: ./doc/arch-design/ch_references.xml:83(para)
msgid "<link xlink:href=\"https://wiki.openstack.org/wiki/HypervisorSupportMatrix\">OpenStack Hypervisor Support Matrix</link>: ​Matrix of supported hypervisors and capabilities when used with OpenStack."
msgstr ""

#: ./doc/arch-design/ch_references.xml:89(para)
msgid "<link xlink:href=\"http://docs.openstack.org/developer/swift/replication_network.html\">OpenStack Object Store (Swift) Replication Reference</link>: Developer documentation of Swift replication."
msgstr ""

#: ./doc/arch-design/ch_references.xml:95(para)
msgid "<link xlink:href=\"http://docs.openstack.org/openstack-ops/\">OpenStack Operations Guide</link>: The OpenStack Operations Guide provides information on setting up and installing OpenStack."
msgstr ""

#: ./doc/arch-design/ch_references.xml:101(para)
msgid "<link xlink:href=\"http://docs.openstack.org/security-guide/\">OpenStack Security Guide</link>: The OpenStack Security Guide provides information on securing OpenStack deployments."
msgstr ""

#: ./doc/arch-design/ch_references.xml:107(para)
msgid "<link xlink:href=\"http://www.openstack.org/marketplace/training\">OpenStack Training Marketplace</link>: The OpenStack Market for training and Vendors providing training on OpenStack."
msgstr ""

#: ./doc/arch-design/ch_references.xml:113(para)
msgid "<link xlink:href=\"https://wiki.openstack.org/wiki/Pci_passthrough#How_to_check_PCI_status_with_PCI_api_paches\">PCI passthrough</link>: The PCI API patches extend the servers/os-hypervisor to show PCI information for instance and compute node, and also provides a resource endpoint to show PCI information."
msgstr ""

#: ./doc/arch-design/ch_references.xml:121(para)
msgid "<link xlink:href=\"https://wiki.openstack.org/wiki/TripleO\">TripleO</link>: TripleO is a program aimed at installing, upgrading and operating OpenStack clouds using OpenStack's own cloud facilities as the foundation."
msgstr ""

#: ./doc/arch-design/network_focus/section_operational_considerations_network_focus.xml:8(title) ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:8(title) ./doc/arch-design/compute_focus/section_operational_considerations_compute_focus.xml:8(title) ./doc/arch-design/multi_site/section_operational_considerations_multi_site.xml:8(title) ./doc/arch-design/hybrid/section_operational_considerations_hybrid.xml:8(title) ./doc/arch-design/massively_scalable/section_operational_considerations_massively_scalable.xml:8(title) ./doc/arch-design/generalpurpose/section_operational_considerations_general_purpose.xml:8(title)
msgid "Operational considerations"
msgstr ""

#: ./doc/arch-design/network_focus/section_operational_considerations_network_focus.xml:9(para)
msgid "Network-focused OpenStack clouds have a number of operational considerations that influence the selected design, including:"
msgstr ""

#: ./doc/arch-design/network_focus/section_operational_considerations_network_focus.xml:13(para)
msgid "Dynamic routing of static routes"
msgstr ""

#: ./doc/arch-design/network_focus/section_operational_considerations_network_focus.xml:16(para)
msgid "Service level agreements (SLAs)"
msgstr ""

#: ./doc/arch-design/network_focus/section_operational_considerations_network_focus.xml:19(para)
msgid "Ownership of user management"
msgstr ""

#: ./doc/arch-design/network_focus/section_operational_considerations_network_focus.xml:22(para)
msgid "An initial network consideration is the selection of a telecom company or transit provider."
msgstr ""

#: ./doc/arch-design/network_focus/section_operational_considerations_network_focus.xml:24(para)
msgid "Make additional design decisions about monitoring and alarming. This can be an internal responsibility or the responsibility of the external provider. In the case of using an external provider, service level agreements (SLAs) likely apply. In addition, other operational considerations such as bandwidth, latency, and jitter can be part of an SLA."
msgstr ""

#: ./doc/arch-design/network_focus/section_operational_considerations_network_focus.xml:30(para)
msgid "Consider the ability to upgrade the infrastructure. As demand for network resources increase, operators add additional IP address blocks and add additional bandwidth capacity. In addition, consider managing hardware and software life cycle events, for example upgrades, decommissioning, and outages, while avoiding service interruptions for tenants."
msgstr ""

#: ./doc/arch-design/network_focus/section_operational_considerations_network_focus.xml:36(para)
msgid "Factor maintainability into the overall network design. This includes the ability to manage and maintain IP addresses as well as the use of overlay identifiers including VLAN tag IDs, GRE tunnel IDs, and MPLS tags. As an example, if you may need to change all of the IP addresses on a network, a process known as renumbering, then the design must support this function."
msgstr ""

#: ./doc/arch-design/network_focus/section_operational_considerations_network_focus.xml:42(para)
msgid "Address network-focused applications when considering certain operational realities. For example, consider the impending exhaustion of IPv4 addresses, the migration to IPv6, and the use of private networks to segregate different types of traffic that an application receives or generates. In the case of IPv4 to IPv6 migrations, applications should follow best practices for storing IP addresses. We recommend you avoid relying on IPv4 features that did not carry over to the IPv6 protocol or have differences in implementation."
msgstr ""

#: ./doc/arch-design/network_focus/section_operational_considerations_network_focus.xml:50(para)
msgid "To segregate traffic, allow applications to create a private tenant network for database and storage network traffic. Use a public network for services that require direct client access from the internet. Upon segregating the traffic, consider quality of service (QoS) and security to ensure each network has the required level of service."
msgstr ""

#: ./doc/arch-design/network_focus/section_operational_considerations_network_focus.xml:55(para)
msgid "Finally, consider the routing of network traffic. For some applications, develop a complex policy framework for routing. To create a routing policy that satisfies business requirements, consider the economic cost of transmitting traffic over expensive links versus cheaper links, in addition to bandwidth, latency, and jitter requirements."
msgstr ""

#: ./doc/arch-design/network_focus/section_operational_considerations_network_focus.xml:61(para)
msgid "Additionally, consider how to respond to network events. As an example, how load transfers from one link to another during a failure scenario could be a factor in the design. If you do not plan network capacity correctly, failover traffic could overwhelm other ports or network links and create a cascading failure scenario. In this case, traffic that fails over to one link overwhelms that link and then moves to the subsequent links until all network traffic stops."
msgstr ""

#. When image changes, this message will be marked fuzzy or untranslated for you.
#. It doesn't matter what you translate it to: it's not used at all.
#: ./doc/arch-design/network_focus/section_prescriptive_examples_network_focus.xml:42(None)
msgid "@@image: '../figures/Network_Web_Services1.png'; md5=7ad46189444753336edd957108a1a92b"
msgstr ""

#. When image changes, this message will be marked fuzzy or untranslated for you.
#. It doesn't matter what you translate it to: it's not used at all.
#: ./doc/arch-design/network_focus/section_prescriptive_examples_network_focus.xml:195(None)
msgid "@@image: '../figures/Network_Cloud_Storage2.png'; md5=3cd3ce6b19b20ecd7d22af03731cc7cd"
msgstr ""

#: ./doc/arch-design/network_focus/section_prescriptive_examples_network_focus.xml:8(title) ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:8(title) ./doc/arch-design/compute_focus/section_prescriptive_examples_compute_focus.xml:8(title) ./doc/arch-design/multi_site/section_prescriptive_examples_multi_site.xml:12(title) ./doc/arch-design/hybrid/section_prescriptive_examples_hybrid.xml:8(title)
msgid "Prescriptive examples"
msgstr ""

#: ./doc/arch-design/network_focus/section_prescriptive_examples_network_focus.xml:9(para)
msgid "An organization designs a large-scale web application with cloud principles in mind. The application scales horizontally in a bursting fashion and generates a high instance count. The application requires an SSL connection to secure data and must not lose connection state to individual servers."
msgstr ""

#: ./doc/arch-design/network_focus/section_prescriptive_examples_network_focus.xml:15(para)
msgid "The figure below depicts an example design for this workload. In this example, a hardware load balancer provides SSL offload functionality and connects to tenant networks in order to reduce address consumption. This load balancer links to the routing architecture as it services the VIP for the application. The router and load balancer use the GRE tunnel ID of the application's tenant network and an IP address within the tenant subnet but outside of the address pool. This is to ensure that the load balancer can communicate with the application's HTTP servers without requiring the consumption of a public IP address."
msgstr ""

#: ./doc/arch-design/network_focus/section_prescriptive_examples_network_focus.xml:27(para)
msgid "Because sessions persist until closed, the routing and switching architecture provides high availability. Switches mesh to each hypervisor and each other, and also provide an MLAG implementation to ensure that layer-2 connectivity does not fail. Routers use VRRP and fully mesh with switches to ensure layer-3 connectivity. Since GRE is provides an overlay network, Networking is present and uses the Open vSwitch agent in GRE tunnel mode. This ensures all devices can reach all other devices and that you can create tenant networks for private addressing links to the load balancer. <placeholder-1/>"
msgstr ""

#: ./doc/arch-design/network_focus/section_prescriptive_examples_network_focus.xml:45(para)
msgid "A web service architecture has many options and optional components. Due to this, it can fit into a large number of other OpenStack designs. A few key components, however, need to be in place to handle the nature of most web-scale workloads. You require the following components:"
msgstr ""

#: ./doc/arch-design/network_focus/section_prescriptive_examples_network_focus.xml:52(para)
msgid "OpenStack Controller services (Image, Identity, Networking and supporting services such as MariaDB and RabbitMQ)"
msgstr ""

#: ./doc/arch-design/network_focus/section_prescriptive_examples_network_focus.xml:57(para)
msgid "OpenStack Compute running KVM hypervisor"
msgstr ""

#: ./doc/arch-design/network_focus/section_prescriptive_examples_network_focus.xml:60(para)
msgid "OpenStack Object Storage"
msgstr ""

#: ./doc/arch-design/network_focus/section_prescriptive_examples_network_focus.xml:63(para)
msgid "Orchestration service"
msgstr ""

#: ./doc/arch-design/network_focus/section_prescriptive_examples_network_focus.xml:66(para)
msgid "Telemetry service"
msgstr ""

#: ./doc/arch-design/network_focus/section_prescriptive_examples_network_focus.xml:69(para)
msgid "Beyond the normal Identity, Compute, Image service, and Object Storage components, we recommend the Orchestration service component to handle the proper scaling of workloads to adjust to demand. Due to the requirement for auto-scaling, the design includes the Telemetry service. Web services tend to be bursty in load, have very defined peak and valley usage patterns and, as a result, benefit from automatic scaling of instances based upon traffic. At a network level, a split network configuration works well with databases residing on private tenant networks since these do not emit a large quantity of broadcast traffic and may need to interconnect to some databases for content."
msgstr ""

#: ./doc/arch-design/network_focus/section_prescriptive_examples_network_focus.xml:83(title)
msgid "Load balancing"
msgstr ""

#: ./doc/arch-design/network_focus/section_prescriptive_examples_network_focus.xml:84(para)
msgid "Load balancing spreads requests across multiple instances. This workload scales well horizontally across large numbers of instances. This enables instances to run without publicly routed IP addresses and instead to rely on the load balancer to provide a globally reachable service. Many of these services do not require direct server return. This aids in address planning and utilization at scale since only the virtual IP (VIP) must be public."
msgstr ""

#: ./doc/arch-design/network_focus/section_prescriptive_examples_network_focus.xml:95(title)
msgid "Overlay networks"
msgstr ""

#: ./doc/arch-design/network_focus/section_prescriptive_examples_network_focus.xml:96(para)
msgid "The overlay functionality design includes OpenStack Networking in Open vSwitch GRE tunnel mode. In this case, the layer-3 external routers pair with VRRP, and switches pair with an implementation of MLAG to ensure that you do not lose connectivity with the upstream routing infrastructure."
msgstr ""

#: ./doc/arch-design/network_focus/section_prescriptive_examples_network_focus.xml:106(title)
msgid "Performance tuning"
msgstr ""

#: ./doc/arch-design/network_focus/section_prescriptive_examples_network_focus.xml:107(para)
msgid "Network level tuning for this workload is minimal. Quality-of-Service (QoS) applies to these workloads for a middle ground Class Selector depending on existing policies. It is higher than a best effort queue but lower than an Expedited Forwarding or Assured Forwarding queue. Since this type of application generates larger packets with longer-lived connections, you can optimize bandwidth utilization for long duration TCP. Normal bandwidth planning applies here with regards to benchmarking a session's usage multiplied by the expected number of concurrent sessions with overhead."
msgstr ""

#: ./doc/arch-design/network_focus/section_prescriptive_examples_network_focus.xml:120(title)
msgid "Network functions"
msgstr ""

#: ./doc/arch-design/network_focus/section_prescriptive_examples_network_focus.xml:121(para)
msgid "Network functions is a broad category but encompasses workloads that support the rest of a system's network. These workloads tend to consist of large amounts of small packets that are very short lived, such as DNS queries or SNMP traps. These messages need to arrive quickly and do not deal with packet loss as there can be a very large volume of them. There are a few extra considerations to take into account for this type of workload and this can change a configuration all the way to the hypervisor level. For an application that generates 10 TCP sessions per user with an average bandwidth of 512 kilobytes per second per flow and expected user count of ten thousand concurrent users, the expected bandwidth plan is approximately 4.88 gigabits per second."
msgstr ""

#: ./doc/arch-design/network_focus/section_prescriptive_examples_network_focus.xml:134(para)
msgid "The supporting network for this type of configuration needs to have a low latency and evenly distributed availability. This workload benefits from having services local to the consumers of the service. Use a multi-site approach as well as deploying many copies of the application to handle load as close as possible to consumers. Since these applications function independently, they do not warrant running overlays to interconnect tenant networks. Overlays also have the drawback of performing poorly with rapid flow setup and may incur too much overhead with large quantities of small packets and therefore we do not recommend them."
msgstr ""

#: ./doc/arch-design/network_focus/section_prescriptive_examples_network_focus.xml:145(para)
msgid "QoS is desirable for some workloads to ensure delivery. DNS has a major impact on the load times of other services and needs to be reliable and provide rapid responses. Configure rules in upstream devices to apply a higher Class Selector to DNS to ensure faster delivery or a better spot in queuing algorithms."
msgstr ""

#: ./doc/arch-design/network_focus/section_prescriptive_examples_network_focus.xml:153(title)
msgid "Cloud storage"
msgstr ""

#: ./doc/arch-design/network_focus/section_prescriptive_examples_network_focus.xml:154(para)
msgid "Another common use case for OpenStack environments is providing a cloud-based file storage and sharing service. You might consider this a storage-focused use case, but its network-side requirements make it a network-focused use case."
msgstr ""

#: ./doc/arch-design/network_focus/section_prescriptive_examples_network_focus.xml:158(para)
msgid "For example, consider a cloud backup application. This workload has two specific behaviors that impact the network. Because this workload is an externally-facing service and an internally-replicating application, it has both <glossterm baseform=\"north-south traffic\">north-south</glossterm> and <glossterm>east-west traffic</glossterm> considerations:"
msgstr ""

#: ./doc/arch-design/network_focus/section_prescriptive_examples_network_focus.xml:167(term)
msgid "north-south traffic"
msgstr ""

#: ./doc/arch-design/network_focus/section_prescriptive_examples_network_focus.xml:169(para)
msgid "When a user uploads and stores content, that content moves into the OpenStack installation. When users download this content, the content moves out from the OpenStack installation. Because this service operates primarily as a backup, most of the traffic moves southbound into the environment. In this situation, it benefits you to configure a network to be asymmetrically downstream because the traffic that enters the OpenStack installation is greater than the traffic that leaves the installation."
msgstr ""

#: ./doc/arch-design/network_focus/section_prescriptive_examples_network_focus.xml:181(term)
msgid "east-west traffic"
msgstr ""

#: ./doc/arch-design/network_focus/section_prescriptive_examples_network_focus.xml:183(para)
msgid "Likely to be fully symmetric. Because replication originates from any node and might target multiple other nodes algorithmically, it is less likely for this traffic to have a larger volume in any specific direction. However this traffic might interfere with north-south traffic."
msgstr ""

#: ./doc/arch-design/network_focus/section_prescriptive_examples_network_focus.xml:198(para)
msgid "This application prioritizes the north-south traffic over east-west traffic: the north-south traffic involves customer-facing data."
msgstr ""

#: ./doc/arch-design/network_focus/section_prescriptive_examples_network_focus.xml:201(para)
msgid "The network design in this case is less dependent on availability and more dependent on being able to handle high bandwidth. As a direct result, it is beneficial to forgo redundant links in favor of bonding those connections. This increases available bandwidth. It is also beneficial to configure all devices in the path, including OpenStack, to generate and pass jumbo frames."
msgstr ""

#: ./doc/arch-design/network_focus/section_architecture_network_focus.xml:7(title) ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:11(title) ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:8(title) ./doc/arch-design/multi_site/section_architecture_multi_site.xml:8(title) ./doc/arch-design/hybrid/section_architecture_hybrid.xml:8(title) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:12(title)
msgid "Architecture"
msgstr ""

#: ./doc/arch-design/network_focus/section_architecture_network_focus.xml:8(para)
msgid "Network-focused OpenStack architectures have many similarities to other OpenStack architecture use cases. There are several factors to consider when designing for a network-centric or network-heavy application environment."
msgstr ""

#: ./doc/arch-design/network_focus/section_architecture_network_focus.xml:12(para)
msgid "Networks exist to serve as a medium of transporting data between systems. It is inevitable that an OpenStack design has inter-dependencies with non-network portions of OpenStack as well as on external systems. Depending on the specific workload, there may be major interactions with storage systems both within and external to the OpenStack environment. For example, in the case of content delivery network, there is twofold interaction with storage. Traffic flows to and from the storage array for ingesting and serving content in a north-south direction. In addition, there is replication traffic flowing in an east-west direction."
msgstr ""

#: ./doc/arch-design/network_focus/section_architecture_network_focus.xml:21(para)
msgid "Compute-heavy workloads may also induce interactions with the network. Some high performance compute applications require network-based memory mapping and data sharing and, as a result, induce a higher network load when they transfer results and data sets. Others may be highly transactional and issue transaction locks, perform their functions, and revoke transaction locks at high rates. This also has an impact on the network performance."
msgstr ""

#: ./doc/arch-design/network_focus/section_architecture_network_focus.xml:28(para)
msgid "Some network dependencies are external to OpenStack. While OpenStack Networking is capable of providing network ports, IP addresses, some level of routing, and overlay networks, there are some other functions that it cannot provide. For many of these, you may require external systems or equipment to fill in the functional gaps. Hardware load balancers are an example of equipment that may be necessary to distribute workloads or offload certain functions. OpenStack Networking provides a tunneling feature, however it is constrained to a Networking-managed region. If the need arises to extend a tunnel beyond the OpenStack region to either another region or an external system, implement the tunnel itself outside OpenStack or use a tunnel management system to map the tunnel or overlay to an external tunnel."
msgstr ""

#: ./doc/arch-design/network_focus/section_architecture_network_focus.xml:41(para)
msgid "Depending on the selected design, Networking itself might not support the required <glossterm baseform=\"Layer-3 network\">layer-3 network</glossterm> functionality. If you choose to use the provider networking mode without running the layer-3 agent, you must install an external router to provide layer-3 connectivity to outside systems."
msgstr ""

#: ./doc/arch-design/network_focus/section_architecture_network_focus.xml:49(para)
msgid "Interaction with orchestration services is inevitable in larger-scale deployments. The Orchestration service is capable of allocating network resource defined in templates to map to tenant networks and for port creation, as well as allocating floating IPs. If there is a requirement to define and manage network resources when using orchestration, we recommend that the design include the Orchestration service to meet the demands of users."
msgstr ""

#: ./doc/arch-design/network_focus/section_architecture_network_focus.xml:57(title)
msgid "Design impacts"
msgstr ""

#: ./doc/arch-design/network_focus/section_architecture_network_focus.xml:58(para)
msgid "A wide variety of factors can affect a network-focused OpenStack architecture. While there are some considerations shared with a general use case, specific workloads related to network requirements influence network design decisions."
msgstr ""

#: ./doc/arch-design/network_focus/section_architecture_network_focus.xml:62(para)
msgid "One decision includes whether or not to use Network Address Translation (NAT) and where to implement it. If there is a requirement for floating IPs instead of public fixed addresses then you must use NAT. An example of this is a DHCP relay that must know the IP of the DHCP server. In these cases it is easier to automate the infrastructure to apply the target IP to a new instance rather than to reconfigure legacy or external systems for each new instance."
msgstr ""

#: ./doc/arch-design/network_focus/section_architecture_network_focus.xml:69(para)
msgid "NAT for floating IPs managed by Networking resides within the hypervisor but there are also versions of NAT that may be running elsewhere. If there is a shortage of IPv4 addresses there are two common methods to mitigate this externally to OpenStack. The first is to run a load balancer either within OpenStack as an instance, or use an external load balancing solution. In the internal scenario, Networking's Load-Balancer-as-a-Service (LBaaS) can manage load balancing software, for example HAproxy. This is specifically to manage the Virtual IP (VIP) while a dual-homed connection from the HAproxy instance connects the public network with the tenant private network that hosts all of the content servers. In the external scenario, a load balancer needs to serve the VIP and also connect to the tenant overlay network through external means or through private addresses."
msgstr ""

#: ./doc/arch-design/network_focus/section_architecture_network_focus.xml:82(para)
msgid "Another kind of NAT that may be useful is protocol NAT. In some cases it may be desirable to use only IPv6 addresses on instances and operate either an instance or an external service to provide a NAT-based transition technology such as NAT64 and DNS64. This provides the ability to have a globally routable IPv6 address while only consuming IPv4 addresses as necessary or in a shared manner."
msgstr ""

#: ./doc/arch-design/network_focus/section_architecture_network_focus.xml:88(para)
msgid "Application workloads affect the design of the underlying network architecture. If a workload requires network-level redundancy, the routing and switching architecture have to accommodate this. There are differing methods for providing this that are dependent on the selected network hardware, the performance of the hardware, and which networking model you deploy. Examples include Link aggregation (LAG) and Hot Standby Router Protocol (HSRP). Also consider whether to deploy OpenStack Networking or legacy networking (nova-network), and which plug-in to select for OpenStack Networking. If using an external system, configure Networking to run <glossterm baseform=\"Layer-2 network\">layer 2</glossterm> with a provider network configuration. For example, implement HSRP to terminate layer-3 connectivity."
msgstr ""

#: ./doc/arch-design/network_focus/section_architecture_network_focus.xml:101(para)
msgid "Depending on the workload, overlay networks may not be the best solution. Where application network connections are small, short lived, or bursty, running a dynamic overlay can generate as much bandwidth as the packets it carries. It also can induce enough latency to cause issues with certain applications. There is an impact to the device generating the overlay which, in most installations, is the hypervisor. This causes performance degradation on packet per second and connection per second rates."
msgstr ""

#: ./doc/arch-design/network_focus/section_architecture_network_focus.xml:109(para)
msgid "Overlays also come with a secondary option that may not be appropriate to a specific workload. While all of them operate in full mesh by default, there might be good reasons to disable this function because it may cause excessive overhead for some workloads. Conversely, other workloads operate without issue. For example, most web services applications do not have major issues with a full mesh overlay network, while some network monitoring tools or storage replication workloads have performance issues with throughput or excessive broadcast traffic."
msgstr ""

#: ./doc/arch-design/network_focus/section_architecture_network_focus.xml:118(para)
msgid "Many people overlook an important design decision: The choice of layer-3 protocols. While OpenStack was initially built with only IPv4 support, Networking now supports IPv6 and dual-stacked networks. Some workloads are possible through the use of IPv6 and IPv6 to IPv4 reverse transition mechanisms such as NAT64 and DNS64 or <glossterm>6to4</glossterm>. This alters the requirements for any address plan as single-stacked and transitional IPv6 deployments can alleviate the need for IPv4 addresses."
msgstr ""

#: ./doc/arch-design/network_focus/section_architecture_network_focus.xml:127(para)
msgid "OpenStack has limited support for dynamic routing, however there are a number of options available by incorporating third party solutions to implement routing within the cloud including network equipment, hardware nodes, and instances. Some workloads perform well with nothing more than static routes and default gateways configured at the layer-3 termination point. In most cases this is sufficient, however some cases require the addition of at least one type of dynamic routing protocol if not multiple protocols. Having a form of interior gateway protocol (IGP) available to the instances inside an OpenStack installation opens up the possibility of use cases for anycast route injection for services that need to use it as a geographic location or failover mechanism. Other applications may wish to directly participate in a routing protocol, either as a passive observer, as in the case of a looking glass, or as an active participant in the form of a route reflector. Since an instance might have a large amount of compute and memory resources, it is trivial to hold an entire unpartitioned routing table and use it to provide services such as network path visibility to other applications or as a monitoring tool."
msgstr ""

#: ./doc/arch-design/network_focus/section_architecture_network_focus.xml:146(para)
msgid "Path maximum transmission unit (MTU) failures are lesser known but harder to diagnose. The MTU must be large enough to handle normal traffic, overhead from an overlay network, and the desired layer-3 protocol. Adding externally built tunnels reduces the MTU packet size. In this case, you must pay attention to the fully calculated MTU size because some systems ignore or drop path MTU discovery packets."
msgstr ""

#: ./doc/arch-design/network_focus/section_architecture_network_focus.xml:155(title)
msgid "Tunable networking components"
msgstr ""

#: ./doc/arch-design/network_focus/section_architecture_network_focus.xml:156(para)
msgid "Consider configurable networking components related to an OpenStack architecture design when designing for network intensive workloads that include MTU and QoS. Some workloads require a larger MTU than normal due to the transfer of large blocks of data. When providing network service for applications such as video streaming or storage replication, we recommend that you configure both OpenStack hardware nodes and the supporting network equipment for jumbo frames where possible. This allows for better use of available bandwidth. Configure jumbo frames across the complete path the packets traverse. If one network component is not capable of handling jumbo frames then the entire path reverts to the default MTU."
msgstr ""

#: ./doc/arch-design/network_focus/section_architecture_network_focus.xml:168(para)
msgid "Quality of Service (QoS) also has a great impact on network intensive workloads as it provides instant service to packets which have a higher priority due to the impact of poor network performance. In applications such as Voice over IP (VoIP), differentiated services code points are a near requirement for proper operation. You can also use QoS in the opposite direction for mixed workloads to prevent low priority but high bandwidth applications, for example backup services, video conferencing, or file sharing, from blocking bandwidth that is needed for the proper operation of other workloads. It is possible to tag file storage traffic as a lower class, such as best effort or scavenger, to allow the higher priority traffic through. In cases where regions within a cloud might be geographically distributed it may also be necessary to plan accordingly to implement WAN optimization to combat latency or packet loss."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:8(title) ./doc/arch-design/storage_focus/section_tech_considerations_storage_focus.xml:8(title) ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:12(title) ./doc/arch-design/multi_site/section_tech_considerations_multi_site.xml:8(title) ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:12(title) ./doc/arch-design/massively_scalable/section_tech_considerations_massively_scalable.xml:12(title) ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:12(title)
msgid "Technical considerations"
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:9(para)
msgid "When you design an OpenStack network architecture, you must consider layer-2 and layer-3 issues. Layer-2 decisions involve those made at the data-link layer, such as the decision to use Ethernet versus Token Ring. Layer-3 decisions involve those made about the protocol layer and the point when IP comes into the picture. As an example, a completely internal OpenStack network can exist at layer 2 and ignore layer 3. In order for any traffic to go outside of that cloud, to another network, or to the Internet, however, you must use a layer-3 router or switch."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:19(para)
msgid "The past few years have seen two competing trends in networking. One trend leans towards building data center network architectures based on layer-2 networking. Another trend treats the cloud environment essentially as a miniature version of the Internet. This approach is radically different from the network architecture approach in the staging environment: the Internet only uses layer-3 routing rather than layer-2 switching."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:27(para)
msgid "A network designed on layer-2 protocols has advantages over one designed on layer-3 protocols. In spite of the difficulties of using a bridge to perform the network role of a router, many vendors, customers, and service providers choose to use Ethernet in as many parts of their networks as possible. The benefits of selecting a layer-2 design are:"
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:35(para)
msgid "Ethernet frames contain all the essentials for networking. These include, but are not limited to, globally unique source addresses, globally unique destination addresses, and error control."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:41(para)
msgid "Ethernet frames can carry any kind of packet. Networking at layer 2 is independent of the layer-3 protocol."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:46(para)
msgid "Adding more layers to the Ethernet frame only slows the networking process down. This is known as 'nodal processing delay'."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:51(para)
msgid "You can add adjunct networking features, for example class of service (CoS) or multicasting, to Ethernet as readily as IP networks."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:56(para)
msgid "VLANs are an easy mechanism for isolating networks."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:60(para)
msgid "Most information starts and ends inside Ethernet frames. Today this applies to data, voice (for example, VoIP), and video (for example, web cameras). The concept is that, if you can perform more of the end-to-end transfer of information from a source to a destination in the form of Ethernet frames, the network benefits more from the advantages of Ethernet. Although it is not a substitute for IP networking, networking at layer 2 can be a powerful adjunct to IP networking."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:68(para)
msgid "Layer-2 Ethernet usage has these advantages over layer-3 IP network usage:"
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:74(para)
msgid "Speed"
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:77(para)
msgid "Reduced overhead of the IP hierarchy."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:80(para)
msgid "No need to keep track of address configuration as systems move around. Whereas the simplicity of layer-2 protocols might work well in a data center with hundreds of physical machines, cloud data centers have the additional burden of needing to keep track of all virtual machine addresses and networks. In these data centers, it is not uncommon for one physical node to support 30-40 instances."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:91(para)
msgid "Networking at the frame level says nothing about the presence or absence of IP addresses at the packet level. Almost all ports, links, and devices on a network of LAN switches still have IP addresses, as do all the source and destination hosts. There are many reasons for the continued need for IP addressing. The largest one is the need to manage the network. A device or link without an IP address is usually invisible to most management applications. Utilities including remote access for diagnostics, file transfer of configurations and software, and similar applications cannot run without IP addresses as well as MAC addresses."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:104(title)
msgid "Layer-2 architecture limitations"
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:105(para)
msgid "Outside of the traditional data center the limitations of layer-2 network architectures become more obvious."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:109(para)
msgid "Number of VLANs is limited to 4096."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:112(para)
msgid "The number of MACs stored in switch tables is limited."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:116(para)
msgid "You must accommodate the need to maintain a set of layer-4 devices to handle traffic control."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:120(para)
msgid "MLAG, often used for switch redundancy, is a proprietary solution that does not scale beyond two devices and forces vendor lock-in."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:125(para)
msgid "It can be difficult to troubleshoot a network without IP addresses and ICMP."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:129(para)
msgid "Configuring <glossterm baseform=\"Address Resolution Protocol (ARP)\">ARP</glossterm> can be complicated on large layer-2 networks."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:134(para)
msgid "All network devices need to be aware of all MACs, even instance MACs, so there is constant churn in MAC tables and network state changes as instances start and stop."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:140(para)
msgid "Migrating MACs (instance migration) to different physical locations are a potential problem if you do not set ARP table timeouts properly."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:145(para)
msgid "It is important to know that layer 2 has a very limited set of network management tools. It is very difficult to control traffic, as it does not have mechanisms to manage the network or shape the traffic, and network troubleshooting is very difficult. One reason for this difficulty is network devices have no IP addresses. As a result, there is no reasonable way to check network delay in a layer-2 network."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:152(para)
msgid "On large layer-2 networks, configuring ARP learning can also be complicated. The setting for the MAC address timer on switches is critical and, if set incorrectly, can cause significant performance problems. As an example, the Cisco default MAC address timer is extremely long. Migrating MACs to different physical locations to support instance migration can be a significant problem. In this case, the network information maintained in the switches could be out of sync with the new location of the instance."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:161(para)
msgid "In a layer-2 network, all devices are aware of all MACs, even those that belong to instances. The network state information in the backbone changes whenever an instance starts or stops. As a result there is far too much churn in the MAC tables on the backbone switches."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:168(title)
msgid "Layer-3 architecture advantages"
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:169(para)
msgid "In the layer 3 case, there is no churn in the routing tables due to instances starting and stopping. The only time there would be a routing state change is in the case of a Top of Rack (ToR) switch failure or a link failure in the backbone itself. Other advantages of using a layer-3 architecture include:"
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:177(para)
msgid "Layer-3 networks provide the same level of resiliency and scalability as the Internet."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:181(para)
msgid "Controlling traffic with routing metrics is straightforward."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:185(para)
msgid "You can configure layer 3 to use <glossterm baseform=\"Border Gateway Protocol (BGP)\">BGP</glossterm> confederation for scalability so core routers have state proportional to the number of racks, not to the number of servers or instances."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:192(para)
msgid "Routing takes instance MAC and IP addresses out of the network core, reducing state churn. Routing state changes only occur in the case of a ToR switch failure or backbone link failure."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:198(para)
msgid "There are a variety of well tested tools, for example ICMP, to monitor and manage traffic."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:202(para)
msgid "Layer-3 architectures enable the use of Quality of Service (QoS) to manage network performance."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:207(title)
msgid "Layer-3 architecture limitations"
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:208(para)
msgid "The main limitation of layer 3 is that there is no built-in isolation mechanism comparable to the VLANs in layer-2 networks. Furthermore, the hierarchical nature of IP addresses means that an instance is on the same subnet as its physical host. This means that you cannot migrate it outside of the subnet easily. For these reasons, network virtualization needs to use IP <glossterm>encapsulation</glossterm> and software at the end hosts for isolation and the separation of the addressing in the virtual layer from the addressing in the physical layer. Other potential disadvantages of layer 3 include the need to design an IP addressing scheme rather than relying on the switches to keep track of the MAC addresses automatically and to configure the interior gateway routing protocol in the switches."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:225(title)
msgid "Network recommendations overview"
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:226(para)
msgid "OpenStack has complex networking requirements for several reasons. Many components interact at different levels of the system stack that adds complexity. Data flows are complex. Data in an OpenStack cloud moves both between instances across the network (also known as East-West), as well as in and out of the system (also known as North-South). Physical server nodes have network requirements that are independent of instance network requirements, which you must isolate from the core network to account for scalability. We recommend functionally separating the networks for security purposes and tuning performance through traffic shaping."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:237(para)
msgid "You must consider a number of important general technical and business factors when planning and designing an OpenStack network. They include:"
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:242(para)
msgid "A requirement for vendor independence. To avoid hardware or software vendor lock-in, the design should not rely on specific features of a vendor's router or switch."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:248(para)
msgid "A requirement to massively scale the ecosystem to support millions of end users."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:252(para)
msgid "A requirement to support indeterminate platforms and applications."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:256(para)
msgid "A requirement to design for cost efficient operations to take advantage of massive scale."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:260(para)
msgid "A requirement to ensure that there is no single point of failure in the cloud ecosystem."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:264(para)
msgid "A requirement for high availability architecture to meet customer SLA requirements."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:268(para)
msgid "A requirement to be tolerant of rack level failure."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:272(para)
msgid "A requirement to maximize flexibility to architect future production environments."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:276(para)
msgid "Bearing in mind these considerations, we recommend the following:"
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:279(para)
msgid "Layer-3 designs are preferable to layer-2 architectures."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:283(para)
msgid "Design a dense multi-path network core to support multi-directional scaling and flexibility."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:287(para)
msgid "Use hierarchical addressing because it is the only viable option to scale network ecosystem."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:291(para)
msgid "Use virtual networking to isolate instance service network traffic from the management and internal network traffic."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:296(para)
msgid "Isolate virtual networks using encapsulation technologies."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:300(para)
msgid "Use traffic shaping for performance tuning."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:303(para)
msgid "Use eBGP to connect to the Internet up-link."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:306(para)
msgid "Use iBGP to flatten the internal traffic on the layer-3 mesh."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:310(para)
msgid "Determine the most effective configuration for block storage network."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:315(title)
msgid "Additional considerations"
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:316(para)
msgid "There are several further considerations when designing a network-focused OpenStack cloud."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:319(title)
msgid "OpenStack Networking versus legacy networking (nova-network) considerations"
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:321(para)
msgid "Selecting the type of networking technology to implement depends on many factors. OpenStack Networking (neutron) and legacy networking (nova-network) both have their advantages and disadvantages. They are both valid and supported options that fit different use cases:"
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:330(th) ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:108(term)
msgid "Legacy networking (nova-network)"
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:331(th)
msgid "OpenStack Networking"
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:335(td)
msgid "Simple, single agent"
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:336(td)
msgid "Complex, multiple agents"
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:339(td)
msgid "More mature, established"
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:340(td)
msgid "Newer, maturing"
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:343(td)
msgid "Flat or VLAN"
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:344(td)
msgid "Flat, VLAN, Overlays, L2-L3, SDN"
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:346(td)
msgid "No plug-in support"
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:347(td)
msgid "Plug-in support for 3rd parties"
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:350(td)
msgid "Scales well"
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:351(td)
msgid "Scaling requires 3rd party plug-ins"
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:354(td)
msgid "No multi-tier topologies"
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:355(td)
msgid "Multi-tier topologies"
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:361(title)
msgid "Redundant networking: ToR switch high availability risk analysis"
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:363(para)
msgid "A technical consideration of networking is the idea that you should install switching gear in a data center with backup switches in case of hardware failure."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:366(para)
msgid "Research indicates the mean time between failures (MTBF) on switches is between 100,000 and 200,000 hours. This number is dependent on the ambient temperature of the switch in the data center. When properly cooled and maintained, this translates to between 11 and 22 years before failure. Even in the worst case of poor ventilation and high ambient temperatures in the data center, the MTBF is still 2-3 years. See <link xlink:href=\"http://www.garrettcom.com/techsupport/papers/ethernet_switch_reliability.pdf\">http://www.garrettcom.com/techsupport/papers/ethernet_switch_reliability.pdf</link> for further information."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:375(para)
msgid "In most cases, it is much more economical to use a single switch with a small pool of spare switches to replace failed units than it is to outfit an entire data center with redundant switches. Applications should tolerate rack level outages without affecting normal operations, since network and compute resources are easily provisioned and plentiful."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:384(title)
msgid "Preparing for the future: IPv6 support"
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:385(para)
msgid "One of the most important networking topics today is the impending exhaustion of IPv4 addresses. In early 2014, ICANN announced that they started allocating the final IPv4 address blocks to the Regional Internet Registries (<link xlink:href=\"http://www.internetsociety.org/deploy360/blog/2014/05/goodbye-ipv4-iana-starts-allocating-final-address-blocks/\">http://www.internetsociety.org/deploy360/blog/2014/05/goodbye-ipv4-iana-starts-allocating-final-address-blocks/</link>). This means the IPv4 address space is close to being fully allocated. As a result, it will soon become difficult to allocate more IPv4 addresses to an application that has experienced growth, or that you expect to scale out, due to the lack of unallocated IPv4 address blocks."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:395(para)
msgid "For network focused applications the future is the IPv6 protocol. IPv6 increases the address space significantly, fixes long standing issues in the IPv4 protocol, and will become essential for network focused applications in the future."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:400(para)
msgid "OpenStack Networking supports IPv6 when configured to take advantage of it. To enable IPv6, create an IPv6 subnet in Networking and use IPv6 prefixes when creating security groups."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:405(title)
msgid "Asymmetric links"
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:406(para)
msgid "When designing a network architecture, the traffic patterns of an application heavily influence the allocation of total bandwidth and the number of links that you use to send and receive traffic. Applications that provide file storage for customers allocate bandwidth and links to favor incoming traffic, whereas video streaming applications allocate bandwidth and links to favor outgoing traffic."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:415(title) ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:18(para) ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:42(term) ./doc/arch-design/multi_site/section_tech_considerations_multi_site.xml:118(title) ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:108(title) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:347(term) ./doc/arch-design/generalpurpose/section_user_requirements_general_purpose.xml:72(term)
msgid "Performance"
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:416(para)
msgid "It is important to analyze the applications' tolerance for latency and jitter when designing an environment to support network focused applications. Certain applications, for example VoIP, are less tolerant of latency and jitter. Where latency and jitter are concerned, certain applications may require tuning of QoS parameters and network device queues to ensure that they queue for transmit immediately or guarantee minimum bandwidth. Since OpenStack currently does not support these functions, consider carefully your selected network plug-in."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:426(para)
msgid "The location of a service may also impact the application or consumer experience. If an application serves differing content to different users it must properly direct connections to those specific locations. Where appropriate, use a multi-site installation for these situations."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:431(para)
msgid "You can implement networking in two separate ways. Legacy networking (nova-network) provides a flat DHCP network with a single broadcast domain. This implementation does not support tenant isolation networks or advanced plug-ins, but it is currently the only way to implement a distributed layer-3 agent using the multi_host configuration. OpenStack Networking (neutron) is the official networking implementation and provides a pluggable architecture that supports a large variety of network methods. Some of these include a layer-2 only provider network model, external device plug-ins, or even OpenFlow controllers."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:442(para)
msgid "Networking at large scales becomes a set of boundary questions. The determination of how large a layer-2 domain must be is based on the amount of nodes within the domain and the amount of broadcast traffic that passes between instances. Breaking layer-2 boundaries may require the implementation of overlay networks and tunnels. This decision is a balancing act between the need for a smaller overhead or a need for a smaller domain."
msgstr ""

#: ./doc/arch-design/network_focus/section_tech_considerations_network_focus.xml:450(para)
msgid "When selecting network devices, be aware that making this decision based on the greatest port density often comes with a drawback. Aggregation switches and routers have not all kept pace with Top of Rack switches and may induce bottlenecks on north-south traffic. As a result, it may be possible for massive amounts of downstream network utilization to impact upstream network devices, impacting service to the cloud. Since OpenStack does not currently provide a mechanism for traffic shaping or rate limiting, it is necessary to implement these features at the network hardware level."
msgstr ""

#: ./doc/arch-design/network_focus/section_user_requirements_network_focus.xml:8(title) ./doc/arch-design/multi_site/section_user_requirements_multi_site.xml:8(title) ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:8(title) ./doc/arch-design/massively_scalable/section_user_requirements_massively_scalable.xml:8(title) ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:334(term) ./doc/arch-design/generalpurpose/section_user_requirements_general_purpose.xml:8(title)
msgid "User requirements"
msgstr ""

#: ./doc/arch-design/network_focus/section_user_requirements_network_focus.xml:9(para)
msgid "Network-focused architectures vary from the general-purpose architecture designs. Certain network-intensive applications influence these architectures. Some of the business requirements that influence the design include:"
msgstr ""

#: ./doc/arch-design/network_focus/section_user_requirements_network_focus.xml:15(para)
msgid "Network latency through slow page loads, degraded video streams, and low quality VoIP sessions impacts the user experience. Users are often not aware of how network design and architecture affects their experiences. Both enterprise customers and end-users rely on the network for delivery of an application. Network performance problems can result in a negative experience for the end-user, as well as productivity and economic loss."
msgstr ""

#: ./doc/arch-design/network_focus/section_user_requirements_network_focus.xml:26(title)
msgid "High availability issues"
msgstr ""

#: ./doc/arch-design/network_focus/section_user_requirements_network_focus.xml:27(para)
msgid "Depending on the application and use case, network-intensive OpenStack installations can have high availability requirements. Financial transaction systems have a much higher requirement for high availability than a development application. Use network availability technologies, for example quality of service (QoS), to improve the network performance of sensitive applications such as VoIP and video streaming."
msgstr ""

#: ./doc/arch-design/network_focus/section_user_requirements_network_focus.xml:34(para)
msgid "High performance systems have SLA requirements for a minimum QoS with regard to guaranteed uptime, latency, and bandwidth. The level of the SLA can have a significant impact on the network architecture and requirements for redundancy in the systems."
msgstr ""

#: ./doc/arch-design/network_focus/section_user_requirements_network_focus.xml:40(title)
msgid "Risks"
msgstr ""

#: ./doc/arch-design/network_focus/section_user_requirements_network_focus.xml:43(term)
msgid "Network misconfigurations"
msgstr ""

#: ./doc/arch-design/network_focus/section_user_requirements_network_focus.xml:45(para)
msgid "Configuring incorrect IP addresses, VLANs, and routers can cause outages to areas of the network or, in the worst-case scenario, the entire cloud infrastructure. Automate network configurations to minimize the opportunity for operator error as it can cause disruptive problems."
msgstr ""

#: ./doc/arch-design/network_focus/section_user_requirements_network_focus.xml:53(term) ./doc/arch-design/compute_focus/section_operational_considerations_compute_focus.xml:55(title) ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:51(title) ./doc/arch-design/generalpurpose/section_operational_considerations_general_purpose.xml:99(title)
msgid "Capacity planning"
msgstr ""

#: ./doc/arch-design/network_focus/section_user_requirements_network_focus.xml:55(para)
msgid "Cloud networks require management for capacity and growth over time. Capacity planning includes the purchase of network circuits and hardware that can potentially have lead times measured in months or years."
msgstr ""

#: ./doc/arch-design/network_focus/section_user_requirements_network_focus.xml:62(term)
msgid "Network tuning"
msgstr ""

#: ./doc/arch-design/network_focus/section_user_requirements_network_focus.xml:64(para)
msgid "Configure cloud networks to minimize link loss, packet loss, packet storms, broadcast storms, and loops."
msgstr ""

#: ./doc/arch-design/network_focus/section_user_requirements_network_focus.xml:69(term)
msgid "Single Point Of Failure (SPOF)"
msgstr ""

#: ./doc/arch-design/network_focus/section_user_requirements_network_focus.xml:71(para)
msgid "Consider high availability at the physical and environmental layers. If there is a single point of failure due to only one upstream link, or only one power supply, an outage can become unavoidable."
msgstr ""

#: ./doc/arch-design/network_focus/section_user_requirements_network_focus.xml:78(term)
msgid "Complexity"
msgstr ""

#: ./doc/arch-design/network_focus/section_user_requirements_network_focus.xml:80(para)
msgid "An overly complex network design can be difficult to maintain and troubleshoot. While device-level configuration can ease maintenance concerns and automated tools can handle overlay networks, avoid or document non-traditional interconnects between functions and specialized hardware to prevent outages."
msgstr ""

#: ./doc/arch-design/network_focus/section_user_requirements_network_focus.xml:89(term)
msgid "Non-standard features"
msgstr ""

#: ./doc/arch-design/network_focus/section_user_requirements_network_focus.xml:91(para)
msgid "There are additional risks that arise from configuring the cloud network to take advantage of vendor specific features. One example is multi-link aggregation (MLAG) used to provide redundancy at the aggregator switch level of the network. MLAG is not a standard and, as a result, each vendor has their own proprietary implementation of the feature. MLAG architectures are not interoperable across switch vendors, which leads to vendor lock-in, and can cause delays or inability when upgrading components."
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:9(para)
msgid "Several operational factors affect the design choices for a general purpose cloud. Operations staff receive tasks regarding the maintenance of cloud environments for larger installations, including:"
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:14(term)
msgid "Maintenance tasks"
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:16(para)
msgid "The storage solution should take into account storage maintenance and the impact on underlying workloads."
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:22(term)
msgid "Reliability and availability"
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:24(para)
msgid "Reliability and availability depend on wide area network availability and on the level of precautions taken by the service provider."
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:31(term)
msgid "Flexibility"
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:33(para)
msgid "Organizations need to have the flexibility to choose between off-premise and on-premise cloud storage options. This relies on relevant decision criteria with potential cost savings. For example, continuity of operations, disaster recovery, security, records retention laws, regulations, and policies."
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:42(para)
msgid "Monitoring and alerting services are vital in cloud environments with high demands on storage resources. These services provide a real-time view into the health and performance of the storage systems. An integrated management console, or other dashboards capable of visualizing SNMP data, is helpful when discovering and resolving issues that arise within the storage cluster."
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:49(para)
msgid "A storage-focused cloud design should include:"
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:52(para)
msgid "Monitoring of physical hardware resources."
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:55(para)
msgid "Monitoring of environmental resources such as temperature and humidity."
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:59(para)
msgid "Monitoring of storage resources such as available storage, memory, and CPU."
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:63(para)
msgid "Monitoring of advanced storage performance data to ensure that storage systems are performing as expected."
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:68(para)
msgid "Monitoring of network resources for service disruptions which would affect access to storage."
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:73(para)
msgid "Centralized log collection."
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:76(para)
msgid "Log analytics capabilities."
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:79(para)
msgid "Ticketing system (or integration with a ticketing system) to track issues."
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:83(para)
msgid "Alerting and notification of responsible teams or automated systems which remediate problems with storage as they arise."
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:88(para)
msgid "Network Operations Center (NOC) staffed and always available to resolve issues."
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:94(title)
msgid "Application awareness"
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:95(para)
msgid "Well-designed applications should be aware of underlying storage subsystems in order to use cloud storage solutions effectively."
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:97(para)
msgid "If natively available replication is not available, operations personnel must be able to modify the application so that they can provide their own replication service. In the event that replication is unavailable, operations personnel can design applications to react such that they can provide their own replication services. An application designed to detect underlying storage systems can function in a wide variety of infrastructures, and still have the same basic behavior regardless of the differences in the underlying infrastructure."
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:109(title)
msgid "Fault tolerance and availability"
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:110(para)
msgid "Designing for fault tolerance and availability of storage systems in an OpenStack cloud is vastly different when comparing the Block Storage and Object Storage services."
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:115(title)
msgid "Block Storage fault tolerance and availability"
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:116(para)
msgid "Configure Block Storage resource nodes with advanced RAID controllers and high performance disks to provide fault tolerance at the hardware level."
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:119(para)
msgid "Deploy high performing storage solutions such as SSD disk drives or flash storage systems for applications requiring extreme performance out of Block Storage devices."
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:122(para)
msgid "In environments that place extreme demands on Block Storage, we recommend using multiple storage pools. In this case, each pool of devices should have a similar hardware design and disk configuration across all hardware nodes in that pool. This allows for a design that provides applications with access to a wide variety of Block Storage pools, each with their own redundancy, availability, and performance characteristics. When deploying multiple pools of storage it is also important to consider the impact on the Block Storage scheduler which is responsible for provisioning storage across resource nodes. Ensuring that applications can schedule volumes in multiple regions, each with their own network, power, and cooling infrastructure, can give tenants the ability to build fault tolerant applications that are distributed across multiple availability zones."
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:137(para)
msgid "In addition to the Block Storage resource nodes, it is important to design for high availability and redundancy of the APIs, and related services that are responsible for provisioning and providing access to storage. We recommend designing a layer of hardware or software load balancers in order to achieve high availability of the appropriate REST API services to provide uninterrupted service. In some cases, it may also be necessary to deploy an additional layer of load balancing to provide access to back-end database services responsible for servicing and storing the state of Block Storage volumes. We also recommend designing a highly available database solution to store the Block Storage databases. Leverage highly available database solutions such as Galera and MariaDB to help keep database services online for uninterrupted access, so that tenants can manage Block Storage volumes."
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:153(para)
msgid "In a cloud with extreme demands on Block Storage, the network architecture should take into account the amount of East-West bandwidth required for instances to make use of the available storage resources. The selected network devices should support jumbo frames for transferring large blocks of data. In some cases, it may be necessary to create an additional back-end storage network dedicated to providing connectivity between instances and Block Storage resources so that there is no contention of network resources."
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:164(title)
msgid "Object Storage fault tolerance and availability"
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:165(para)
msgid "While consistency and partition tolerance are both inherent features of the Object Storage service, it is important to design the overall storage architecture to ensure that the implemented system meets those goals. The OpenStack Object Storage service places a specific number of data replicas as objects on resource nodes. These replicas are distributed throughout the cluster based on a consistent hash ring which exists on all nodes in the cluster."
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:173(para)
msgid "Design the Object Storage system with a sufficient number of zones to provide quorum for the number of replicas defined. For example, with three replicas configured in the Swift cluster, the recommended number of zones to configure within the Object Storage cluster in order to achieve quorum is five. While it is possible to deploy a solution with fewer zones, the implied risk of doing so is that some data may not be available and API requests to certain objects stored in the cluster might fail. For this reason, ensure you properly account for the number of zones in the Object Storage cluster."
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:183(para)
msgid "Each Object Storage zone should be self-contained within its own availability zone. Each availability zone should have independent access to network, power and cooling infrastructure to ensure uninterrupted access to data. In addition, a pool of Object Storage proxy servers providing access to data stored on the object nodes should service each availability zone. Object proxies in each region should leverage local read and write affinity so that local storage resources facilitate access to objects wherever possible. We recommend deploying upstream load balancing to ensure that proxy services are distributed across the multiple zones and, in some cases, it may be necessary to make use of third-party solutions to aid with geographical distribution of services."
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:196(para)
msgid "A zone within an Object Storage cluster is a logical division. Any of the following may represent a zone:"
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:200(para)
msgid "A disk within a single node"
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:205(para)
msgid "One zone per node"
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:210(para)
msgid "Zone per collection of nodes"
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:215(para)
msgid "Multiple racks"
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:220(para)
msgid "Multiple DCs"
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:225(para)
msgid "Selecting the proper zone design is crucial for allowing the Object Storage cluster to scale while providing an available and redundant storage system. It may be necessary to configure storage policies that have different requirements with regards to replicas, retention and other factors that could heavily affect the design of storage in a specific zone."
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:236(title)
msgid "Scaling storage services"
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:237(para)
msgid "Adding storage capacity and bandwidth is a very different process when comparing the Block and Object Storage services. While adding Block Storage capacity is a relatively simple process, adding capacity and bandwidth to the Object Storage systems is a complex task that requires careful planning and consideration during the design phase."
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:245(title)
msgid "Scaling Block Storage"
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:246(para)
msgid "You can upgrade Block Storage pools to add storage capacity without interrupting the overall Block Storage service. Add nodes to the pool by installing and configuring the appropriate hardware and software and then allowing that node to report in to the proper storage pool via the message bus. This is because Block Storage nodes report into the scheduler service advertising their availability. After the node is online and available, tenants can make use of those storage resources instantly."
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:256(para)
msgid "In some cases, the demand on Block Storage from instances may exhaust the available network bandwidth. As a result, design network infrastructure that services Block Storage resources in such a way that you can add capacity and bandwidth easily. This often involves the use of dynamic routing protocols or advanced networking solutions to add capacity to downstream devices easily. Both the front-end and back-end storage network designs should encompass the ability to quickly and easily add capacity and bandwidth."
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:268(title)
msgid "Scaling Object Storage"
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:269(para)
msgid "Adding back-end storage capacity to an Object Storage cluster requires careful planning and consideration. In the design phase, it is important to determine the maximum partition power required by the Object Storage service, which determines the maximum number of partitions which can exist. Object Storage distributes data among all available storage, but a partition cannot span more than one disk, so the maximum number of partitions can only be as high as the number of disks."
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:278(para)
msgid "For example, a system that starts with a single disk and a partition power of 3 can have 8 (2^3) partitions. Adding a second disk means that each has 4 partitions. The one-disk-per-partition limit means that this system can never have more than 8 disks, limiting its scalability. However, a system that starts with a single disk and a partition power of 10 can have up to 1024 (2^10) disks."
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:285(para)
msgid "As you add back-end storage capacity to the system, the partition maps redistribute data amongst the storage nodes. In some cases, this replication consists of extremely large data sets. In these cases, we recommend using back-end replication links that do not contend with tenants' access to data."
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:291(para)
msgid "As more tenants begin to access data within the cluster and their data sets grow, it is necessary to add front-end bandwidth to service data access requests. Adding front-end bandwidth to an Object Storage cluster requires careful planning and design of the Object Storage proxies that tenants use to gain access to the data, along with the high availability solutions that enable easy scaling of the proxy layer. We recommend designing a front-end load balancing layer that tenants and consumers use to gain access to data stored within the cluster. This load balancing layer may be distributed across zones, regions or even across geographic boundaries, which may also require that the design encompass geo-location solutions."
msgstr ""

#: ./doc/arch-design/storage_focus/section_operational_considerations_storage_focus.xml:304(para)
msgid "In some cases, you must add bandwidth and capacity to the network resources servicing requests between proxy servers and storage nodes. For this reason, the network architecture used for access to storage nodes and proxy servers should make use of a design which is scalable."
msgstr ""

#: ./doc/arch-design/storage_focus/section_tech_considerations_storage_focus.xml:9(para)
msgid "Some of the key technical considerations that are critical to a storage-focused OpenStack design architecture include:"
msgstr ""

#: ./doc/arch-design/storage_focus/section_tech_considerations_storage_focus.xml:14(term)
msgid "Input-Output requirements"
msgstr ""

#: ./doc/arch-design/storage_focus/section_tech_considerations_storage_focus.xml:16(para)
msgid "Input-Output performance requirements require researching and modeling before deciding on a final storage framework. Running benchmarks for Input-Output performance provides a baseline for expected performance levels. If these tests include details, then the resulting data can help model behavior and results during different workloads. Running scripted smaller benchmarks during the life cycle of the architecture helps record the system health at different points in time. The data from these scripted benchmarks assist in future scoping and gaining a deeper understanding of an organization's needs."
msgstr ""

#: ./doc/arch-design/storage_focus/section_tech_considerations_storage_focus.xml:32(term)
msgid "Scale"
msgstr ""

#: ./doc/arch-design/storage_focus/section_tech_considerations_storage_focus.xml:34(para)
msgid "Scaling storage solutions in a storage-focused OpenStack architecture design is driven by initial requirements, including <glossterm>IOPS</glossterm>, capacity, bandwidth, and future needs. Planning capacity based on projected needs over the course of a budget cycle is important for a design. The architecture should balance cost and capacity, while also allowing flexibility to implement new technologies and methods as they become available."
msgstr ""

#: ./doc/arch-design/storage_focus/section_tech_considerations_storage_focus.xml:49(para)
msgid "Designing security around data has multiple points of focus that vary depending on SLAs, legal requirements, industry regulations, and certifications needed for systems or people. Consider compliance with HIPPA, ISO9000, and SOX based on the type of data. For certain organizations, multiple levels of access control are important."
msgstr ""

#: ./doc/arch-design/storage_focus/section_tech_considerations_storage_focus.xml:58(term)
msgid "OpenStack compatibility"
msgstr ""

#: ./doc/arch-design/storage_focus/section_tech_considerations_storage_focus.xml:60(para)
msgid "Interoperability and integration with OpenStack can be paramount in deciding on a storage hardware and storage management platform. Interoperability and integration includes factors such as OpenStack Block Storage interoperability, OpenStack Object Storage compatibility, and hypervisor compatibility (which affects the ability to use storage for ephemeral instance storage)."
msgstr ""

#: ./doc/arch-design/storage_focus/section_tech_considerations_storage_focus.xml:71(term)
msgid "Storage management"
msgstr ""

#: ./doc/arch-design/storage_focus/section_tech_considerations_storage_focus.xml:73(para)
msgid "You must address a range of storage management-related considerations in the design of a storage-focused OpenStack cloud. These considerations include, but are not limited to, backup strategy (and restore strategy, since a backup that cannot be restored is useless), data valuation-hierarchical storage management, retention strategy, data placement, and workflow automation."
msgstr ""

#: ./doc/arch-design/storage_focus/section_tech_considerations_storage_focus.xml:85(term)
msgid "Data grids"
msgstr ""

#: ./doc/arch-design/storage_focus/section_tech_considerations_storage_focus.xml:87(para)
msgid "Data grids are helpful when answering questions around data valuation. Data grids improve decision making through correlation of access patterns, ownership, and business-unit revenue with other metadata values to deliver actionable information about data."
msgstr ""

#: ./doc/arch-design/storage_focus/section_tech_considerations_storage_focus.xml:95(para)
msgid "When building a storage-focused OpenStack architecture, strive to build a flexible design based on an industry standard core. One way of accomplishing this might be through the use of different back ends serving different use cases."
msgstr ""

#. When image changes, this message will be marked fuzzy or untranslated for you.
#. It doesn't matter what you translate it to: it's not used at all.
#: ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:36(None)
msgid "@@image: '../figures/Storage_Object.png'; md5=ad0b4ee39c96ab081a368ef7857479a5"
msgstr ""

#. When image changes, this message will be marked fuzzy or untranslated for you.
#. It doesn't matter what you translate it to: it's not used at all.
#: ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:97(None)
msgid "@@image: '../figures/Storage_Hadoop3.png'; md5=bdc6373caede70b37209de260616b255"
msgstr ""

#. When image changes, this message will be marked fuzzy or untranslated for you.
#. It doesn't matter what you translate it to: it's not used at all.
#: ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:131(None)
msgid "@@image: '../figures/Storage_Database_+_Object5.png'; md5=a0cb2374c3515b8f3203ebdc7bb7dbbf"
msgstr ""

#: ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:9(para)
msgid "Storage-focused architecture depends on specific use cases. This section discusses three example use cases:"
msgstr ""

#: ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:13(para)
msgid "An object store with a RESTful interface"
msgstr ""

#: ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:18(para)
msgid "Compute analytics with parallel file systems"
msgstr ""

#: ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:23(para)
msgid "High performance database"
msgstr ""

#: ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:28(para)
msgid "The example below shows a REST interface without a high performance requirement."
msgstr ""

#: ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:30(para)
msgid "Swift is a highly scalable object store that is part of the OpenStack project. This diagram explains the example architecture: <placeholder-1/>"
msgstr ""

#: ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:40(para)
msgid "The example REST interface, presented as a traditional Object store running on traditional spindles, does not require a high performance caching tier."
msgstr ""

#: ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:43(para)
msgid "This example uses the following components:"
msgstr ""

#: ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:44(para) ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:149(para)
msgid "Network:"
msgstr ""

#: ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:47(para)
msgid "10 GbE horizontally scalable spine leaf back-end storage and front end network."
msgstr ""

#: ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:51(para) ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:156(para)
msgid "Storage hardware:"
msgstr ""

#: ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:54(para)
msgid "10 storage servers each with 12x4 TB disks equaling 480 TB total space with approximately 160 TB of usable space after replicas."
msgstr ""

#: ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:59(para)
msgid "Proxy:"
msgstr ""

#: ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:62(para) ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:171(para)
msgid "3x proxies"
msgstr ""

#: ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:65(para) ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:174(para)
msgid "2x10 GbE bonded front end"
msgstr ""

#: ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:68(para) ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:177(para)
msgid "2x10 GbE back-end bonds"
msgstr ""

#: ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:71(para) ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:180(para)
msgid "Approximately 60 Gb of total bandwidth to the back-end storage cluster"
msgstr ""

#: ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:76(para)
msgid "It may be necessary to implement a 3rd-party caching layer for some applications to achieve suitable performance."
msgstr ""

#: ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:81(title)
msgid "Compute analytics with Data processing service"
msgstr ""

#: ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:82(para)
msgid "Analytics of large data sets are dependent on the performance of the storage system. Clouds using storage systems such as Hadoop Distributed File System (HDFS) have inefficiencies which can cause performance issues."
msgstr ""

#: ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:87(para)
msgid "One potential solution to this problem is the implementation of storage systems designed for performance. Parallel file systems have previously filled this need in the HPC space and are suitable for large scale performance-orientated systems."
msgstr ""

#: ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:91(para)
msgid "OpenStack has integration with Hadoop to manage the Hadoop cluster within the cloud. The following diagram shows an OpenStack store with a high performance requirement: <placeholder-1/>"
msgstr ""

#: ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:101(para)
msgid "The hardware requirements and configuration are similar to those of the High Performance Database example below. In this case, the architecture uses Ceph's Swift-compatible REST interface, features that allow for connecting a caching pool to allow for acceleration of the presented pool."
msgstr ""

#: ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:111(title)
msgid "High performance database with Database service"
msgstr ""

#: ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:112(para)
msgid "Databases are a common workload that benefit from high performance storage back ends. Although enterprise storage is not a requirement, many environments have existing storage that OpenStack cloud can use as back ends. You can create a storage pool to provide block devices with OpenStack Block Storage for instances as well as object interfaces. In this example, the database I-O requirements are high and demand storage presented from a fast SSD pool."
msgstr ""

#: ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:119(para)
msgid "A storage system presents a LUN backed by a set of SSDs using a traditional storage array with OpenStack Block Storage integration or a storage platform such as Ceph or Gluster."
msgstr ""

#: ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:123(para)
msgid "This system can provide additional performance. For example, in the database example below, a portion of the SSD pool can act as a block device to the Database server. In the high performance analytics example, the inline SSD cache layer accelerates the REST interface."
msgstr ""

#: ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:134(para)
msgid "In this example, Ceph presents a Swift-compatible REST interface, as well as a block level storage from a distributed storage cluster. It is highly flexible and has features that enable reduced cost of operations such as self healing and auto balancing. Using erasure coded pools are a suitable way of maximizing the amount of usable space."
msgstr ""

#: ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:141(para)
msgid "There are special considerations around erasure coded pools. For example, higher computational requirements and limitations on the operations allowed on an object; erasure coded pools do not support partial writes."
msgstr ""

#: ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:147(para)
msgid "Using Ceph as an applicable example, a potential architecture would have the following requirements:"
msgstr ""

#: ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:152(para)
msgid "10 GbE horizontally scalable spine leaf back-end storage and front-end network"
msgstr ""

#: ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:159(para)
msgid "5 storage servers for caching layer 24x1 TB SSD"
msgstr ""

#: ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:163(para)
msgid "10 storage servers each with 12x4 TB disks which equals 480 TB total space with about approximately 160 TB of usable space after 3 replicas"
msgstr ""

#: ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:168(para)
msgid "REST proxy:"
msgstr ""

#: ./doc/arch-design/storage_focus/section_prescriptive_examples_storage_focus.xml:184(para)
msgid "Using an SSD cache layer, you can present block devices directly to hypervisors or instances. The REST interface can also use the SSD cache systems as an inline cache."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:12(para)
msgid "Consider the following factors when selecting storage hardware:"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:15(para) ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:35(term) ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:144(term) ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:374(term) ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:35(para) ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:142(para) ./doc/arch-design/multi_site/section_user_requirements_multi_site.xml:99(title) ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:17(term) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:95(term) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:229(term) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:534(term) ./doc/arch-design/generalpurpose/section_user_requirements_general_purpose.xml:24(term)
msgid "Cost"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:21(para)
msgid "Reliability"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:24(para)
msgid "Storage-focused OpenStack clouds must address I/O intensive workloads. These workloads are not CPU intensive, nor are they consistently network intensive. The network may be heavily utilized to transfer storage, but they are not otherwise network intensive."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:29(para)
msgid "The selection of storage hardware determines the overall performance and scalability of a storage-focused OpenStack design architecture. Several factors impact the design process, including:"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:37(para)
msgid "The cost of components affects which storage architecture and hardware you choose."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:44(para)
msgid "The latency of storage I/O requests indicates performance. Performance requirements affect which solution you choose."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:49(term) ./doc/arch-design/hybrid/section_architecture_hybrid.xml:117(para) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:243(term) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:472(term)
msgid "Scalability"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:51(para)
msgid "Scalability refers to how the storage solution performs as it expands to its maximum size. Storage solutions that perform well in small configurations but have degraded performance in large configurations are not scalable. A solution that performs well at maximum expansion is scalable. Large deployments require a storage solution that performs well as it expands."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:61(para)
msgid "Latency is a key consideration in a storage-focused OpenStack cloud. Using solid-state disks (SSDs) to minimize latency and, to reduce CPU delays caused by waiting for the storage, increases performance. Use RAID controller cards in compute hosts to improve the performance of the underlying disk subsystem."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:66(para)
msgid "Depending on the storage architecture, you can adopt a scale-out solution, or use a highly expandable and scalable centralized storage array. If a centralized storage array is the right fit for your requirements, then the array vendor determines the hardware selection. It is possible to build a storage array using commodity hardware with Open Source software, but requires people with expertise to build such a system."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:73(para)
msgid "On the other hand, a scale-out storage solution that uses direct-attached storage (DAS) in the servers may be an appropriate choice. This requires configuration of the server hardware to support the storage solution."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:77(para)
msgid "Considerations affecting storage architecture (and corresponding storage hardware) of a Storage-focused OpenStack cloud include:"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:81(term) ./doc/arch-design/introduction/section_methodology.xml:102(term) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:281(term) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:459(term)
msgid "Connectivity"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:83(para)
msgid "Based on the selected storage solution, ensure the connectivity matches the storage solution requirements. We recommended confirming that the network characteristics minimize latency to boost the overall performance of the design."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:91(term)
msgid "Latency"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:93(para)
msgid "Determine if the use case has consistent or highly variable latency."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:98(term)
msgid "Throughput"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:100(para)
msgid "Ensure that the storage solution throughput is optimized for your application requirements."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:106(term) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:311(term)
msgid "Server hardware"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:108(para)
msgid "Use of DAS impacts the server hardware choice and affects host density, instance density, power density, OS-hypervisor, and management tools."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:117(title)
msgid "Compute (server) hardware selection"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:118(para)
msgid "Four opposing factors determine the compute (server) hardware selection:"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:122(term) ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:26(para) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:73(term)
msgid "Server density"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:124(para) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:75(para)
msgid "A measure of how many servers can fit into a given measure of physical space, such as a rack unit [U]."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:130(term) ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:29(para) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:81(term)
msgid "Resource capacity"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:132(para)
msgid "The number of CPU cores, how much RAM, or how much storage a given server delivers."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:137(term) ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:32(para) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:88(term) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:255(term)
msgid "Expandability"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:139(para)
msgid "The number of additional resources you can add to a server before it reaches capacity."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:146(para)
msgid "The relative cost of the hardware weighed against the level of design effort needed to build the system."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:152(para)
msgid "You must weigh the dimensions against each other to determine the best design for the desired purpose. For example, increasing server density can mean sacrificing resource capacity or expandability. Increasing resource capacity and expandability can increase cost but decrease server density. Decreasing cost often means decreasing supportability, server density, resource capacity, and expandability."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:160(para)
msgid "Compute capacity (CPU cores and RAM capacity) is a secondary consideration for selecting server hardware. As a result, the required server hardware must supply adequate CPU sockets, additional CPU cores, and more RAM; network connectivity and storage capacity are not as critical. The hardware needs to provide enough network connectivity and storage capacity to meet the user requirements, however they are not the primary consideration."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:168(para)
msgid "Some server hardware form factors are better suited to storage-focused designs than others. The following is a list of these form factors:"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:173(para)
msgid "Most blade servers support dual-socket multi-core CPUs. Choose either full width or full height blades to avoid the limit. High density blade servers support up to 16 servers in only 10 rack units using half height or half width blades."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:179(para)
msgid "This decreases density by 50% (only 8 servers in 10 U) if a full width or full height option is used."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:185(para)
msgid "1U rack-mounted servers have the ability to offer greater server density than a blade server solution, but are often limited to dual-socket, multi-core CPU configurations."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:189(para)
msgid "Due to cooling requirements, it is rare to see 1U rack-mounted servers with more than 2 CPU sockets."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:192(para)
msgid "To obtain greater than dual-socket support in a 1U rack-mount form factor, customers need to buy their systems from Original Design Manufacturers (ODMs) or second-tier manufacturers."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:197(para)
msgid "This may cause issues for organizations that have preferred vendor policies or concerns with support and hardware warranties of non-tier 1 vendors."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:204(para)
msgid "2U rack-mounted servers provide quad-socket, multi-core CPU support but with a corresponding decrease in server density (half the density offered by 1U rack-mounted servers)."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:210(para)
msgid "Larger rack-mounted servers, such as 4U servers, often provide even greater CPU capacity. Commonly supporting four or even eight CPU sockets. These servers have greater expandability but such servers have much lower server density and usually greater hardware cost."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:218(para)
msgid "Rack-mounted servers that support multiple independent servers in a single 2U or 3U enclosure, \"sled servers\", deliver increased density as compared to a typical 1U-2U rack-mounted servers."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:224(para)
msgid "Other factors that influence server hardware selection for a storage-focused OpenStack design architecture include:"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:229(term) ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:93(para) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:161(term)
msgid "Instance density"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:231(para)
msgid "In this architecture, instance density and CPU-RAM oversubscription are lower. You require more hosts to support the anticipated scale, especially if the design uses dual-socket hardware designs."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:239(term) ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:96(para) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:173(term)
msgid "Host density"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:241(para)
msgid "Another option to address the higher host count is to use a quad-socket platform. Taking this approach decreases host density which also increases rack count. This configuration affects the number of power connections and also impacts network and cooling requirements."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:250(term) ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:99(para)
msgid "Power and cooling density"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:252(para)
msgid "The power and cooling density requirements might be lower than with blade, sled, or 1U server designs due to lower host density (by using 2U, 3U or even 4U server designs). For data centers with older infrastructure, this might be a desirable feature."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:261(para)
msgid "Storage-focused OpenStack design architecture server hardware selection should focus on a \"scale-up\" versus \"scale-out\" solution. The determination of which is the best solution (a smaller number of larger hosts or a larger number of smaller hosts), depends on a combination of factors including cost, power, cooling, physical rack and floor space, support-warranty, and manageability."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:271(title)
msgid "Networking hardware selection"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:272(para)
msgid "Key considerations for the selection of networking hardware include:"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:275(term) ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:109(para) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:397(term)
msgid "Port count"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:277(para)
msgid "The user requires networking hardware that has the requisite port count."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:282(term) ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:112(para) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:404(term)
msgid "Port density"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:284(para)
msgid "The physical space required to provide the requisite port count affects the network design. A switch that provides 48 10GbE ports in 1U has a much higher port density than a switch that provides 24 10GbE ports in 2U. On a general scale, a higher port density leaves more rack space for compute or storage components which is preferred. It is also important to consider fault domains and power density. Finally, higher density switches are more expensive, therefore it is important not to over design the network."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:298(term) ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:115(para) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:419(term)
msgid "Port speed"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:300(para) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:421(para)
msgid "The networking hardware must support the proposed network speed, for example: 1GbE, 10GbE, or 40GbE (or even 100GbE)."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:306(term) ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:118(para) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:428(term)
msgid "Redundancy"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:308(para)
msgid "User requirements for high availability and cost considerations influence the required level of network hardware redundancy. Achieve network redundancy by adding redundant power supplies or paired switches."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:313(para)
msgid "If this is a requirement, the hardware must support this configuration. User requirements determine if a completely redundant network infrastructure is required."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:321(term) ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:121(para) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:439(term)
msgid "Power requirements"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:323(para)
msgid "Ensure that the physical data center provides the necessary power for the selected network hardware. This is not an issue for top of rack (ToR) switches, but may be an issue for spine switches in a leaf and spine fabric, or end of row (EoR) switches."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:332(term)
msgid "Protocol support"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:334(para)
msgid "It is possible to gain more performance out of a single storage system by using specialized network technologies such as RDMA, SRP, iSER and SCST. The specifics for using these technologies is beyond the scope of this book."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:345(title) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:504(title) ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:261(title)
msgid "Software selection"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:346(para)
msgid "Factors that influence the software selection for a storage-focused OpenStack architecture design include:"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:350(para) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:509(para)
msgid "Operating system (OS) and hypervisor"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:356(para) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:515(para) ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:452(title)
msgid "Supplemental software"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:359(para)
msgid "Design decisions made in each of these areas impacts the rest of the OpenStack architecture design."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:364(title) ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:136(title) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:521(title)
msgid "Operating system and hypervisor"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:365(para)
msgid "Operating system (OS) and hypervisor have a significant impact on the overall design and also affect server hardware selection. Ensure the selected operating system and hypervisor combination support the storage hardware and work with the networking hardware selection and topology."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:370(para)
msgid "Operating system and hypervisor selection affect the following areas:"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:376(para)
msgid "Selecting a commercially supported hypervisor, such as Microsoft Hyper-V, results in a different cost model than a community-supported open source hypervisor like Kinstance or Xen. Similarly, choosing Ubuntu over Red Hat (or vice versa) impacts cost due to support contracts. However, business or application requirements might dictate a specific or commercially supported hypervisor."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:388(term) ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:145(para) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:548(term)
msgid "Supportability"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:390(para)
msgid "Staff must have training with the chosen hypervisor. Consider the cost of training when choosing a solution. The support of a commercial product such as Red Hat, SUSE, or Windows, is the responsibility of the OS vendor. If an open source platform is chosen, the support comes from in-house resources."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:400(term) ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:148(para) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:559(term)
msgid "Management tools"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:402(para)
msgid "Ubuntu and Kinstance use different management tools than VMware vSphere. Although both OS and hypervisor combinations are supported by OpenStack, there are varying impacts to the rest of the design as a result of the selection of one combination versus the other."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:411(term) ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:151(para) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:571(term)
msgid "Scale and performance"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:413(para)
msgid "Ensure the selected OS and hypervisor combination meet the appropriate scale and performance requirements needed for this storage focused OpenStack cloud. The chosen architecture must meet the targeted instance-host ratios with the selected OS-hypervisor combination."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:424(para)
msgid "Ensure the design can accommodate the regular periodic installation of application security patches while maintaining the required workloads. The frequency of security patches for the proposed OS-hypervisor combination impacts performance and the patch installation process could affect maintenance windows."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:434(term) ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:157(para) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:593(term)
msgid "Supported features"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:436(para)
msgid "Selecting the OS-hypervisor combination often determines the required features of OpenStack. Certain features are only available with specific OSes or hypervisors. For example, if certain features are not available, you might need to modify the design to meet user requirements."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:444(term) ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:160(para) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:602(term) ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:349(term)
msgid "Interoperability"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:446(para)
msgid "The OS-hypervisor combination should be chosen based on the interoperability with one another, and other OS-hyervisor combinations. Operational and troubleshooting tools for one OS-hypervisor combination may differ from the tools used for another OS-hypervisor combination. As a result, the design must address if the two sets of tools need to interoperate."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:461(para)
msgid "The OpenStack components you choose can have a significant impact on the overall design. While there are certain components that are always present (Compute and Image service, for example), there are other services that may not be required. As an example, a certain design may not require the Orchestration service. Omitting Orchestration would not typically have a significant impact on the overall design, however, if the architecture uses a replacement for OpenStack Object Storage for its storage component, this could potentially have significant impacts on the rest of the design."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:471(para)
msgid "A storage-focused design might require the ability to use Orchestration to launch instances with Block Storage volumes to perform storage-intensive processing."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:474(para)
msgid "A storage-focused OpenStack design architecture uses the following components:"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:478(para) ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:232(para)
msgid "OpenStack Identity (keystone)"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:481(para)
msgid "OpenStack dashboard (horizon)"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:484(para)
msgid "OpenStack Compute (nova) (including the use of multiple hypervisor drivers)"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:488(para)
msgid "OpenStack Object Storage (swift) (or another object storage solution)"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:492(para) ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:256(para)
msgid "OpenStack Block Storage (cinder)"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:495(para) ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:229(para)
msgid "OpenStack Image service (glance)"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:498(para)
msgid "OpenStack Networking (neutron) or legacy networking (nova-network)"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:502(para)
msgid "Excluding certain OpenStack components may limit or constrain the functionality of other components. If a design opts to include Orchestration but exclude Telemetry, then the design cannot take advantage of Orchestration's auto scaling functionality (which relies on information from Telemetry). Due to the fact that you can use Orchestration to spin up a large number of instances to perform the compute-intensive processing, we strongly recommend including Orchestration in a compute-focused architecture design."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:514(title) ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:209(title) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:631(title)
msgid "Networking software"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:515(para)
msgid "OpenStack Networking (neutron) provides a wide variety of networking services for instances. There are many additional networking software packages that may be useful to manage the OpenStack components themselves. Some examples include HAProxy, Keepalived, and various routing daemons (like Quagga). The <citetitle>OpenStack High Availability Guide</citetitle> describes some of these software packages, HAProxy in particular. See the <link xlink:href=\"http://docs.openstack.org/ha-guide/networking-ha.html\">Network controller cluster stack chapter</link> of the OpenStack High Availability Guide."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:528(title) ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:224(title) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:667(title)
msgid "Management software"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:529(para)
msgid "Management software includes software for providing:"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:532(para)
msgid "Clustering"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:537(para)
msgid "Logging"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:542(para) ./doc/arch-design/compute_focus/section_prescriptive_examples_compute_focus.xml:136(title) ./doc/arch-design/compute_focus/section_operational_considerations_compute_focus.xml:34(title) ./doc/arch-design/generalpurpose/section_operational_considerations_general_purpose.xml:56(title)
msgid "Monitoring"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:547(para)
msgid "Alerting"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:553(para)
msgid "The factors for determining which software packages in this category to select is outside the scope of this design guide."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:557(para)
msgid "The availability design requirements determine the selection of Clustering Software, such as Corosync or Pacemaker. The availability of the cloud infrastructure and the complexity of supporting the configuration after deployment determines the impact of including these software packages. The <citetitle>OpenStack High Availability Guide</citetitle> provides more details on the installation and configuration of Corosync and Pacemaker."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:565(para)
msgid "Operational considerations determine the requirements for logging, monitoring, and alerting. Each of these sub-categories includes options. For example, in the logging sub-category you could select Logstash, Splunk, Log Insight, or another log aggregation-consolidation tool. Store logs in a centralized location to facilitate performing analytics against the data. Log data analytics engines can also provide automation and issue notification, by providing a mechanism to both alert and automatically attempt to remediate some of the more commonly known issues."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:576(para)
msgid "If you require any of these software packages, the design must account for the additional resource consumption. Some other potential design impacts include:"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:581(para)
msgid "OS-Hypervisor combination: Ensure that the selected logging, monitoring, or alerting tools support the proposed OS-hypervisor combination."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:586(para) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:697(para)
msgid "Network hardware: The network hardware selection needs to be supported by the logging, monitoring, and alerting software."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:594(title) ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:254(title) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:705(title)
msgid "Database software"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:595(para)
msgid "Most OpenStack components require access to back-end database services to store state and configuration information. Choose an appropriate back-end database which satisfies the availability and fault tolerance requirements of the OpenStack services."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:600(para)
msgid "MySQL is the default database for OpenStack, but other compatible databases are available."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:603(para)
msgid "Telemetry uses MongoDB."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:607(para)
msgid "The chosen high availability database solution changes according to the selected database. MySQL, for example, provides several options. Use a replication technology such as Galera for active-active clustering. For active-passive use some form of shared storage. Each of these potential solutions has an impact on the design:"
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:615(para)
msgid "Solutions that employ Galera/MariaDB require at least three MySQL nodes."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:619(para)
msgid "MongoDB has its own design considerations for high availability."
msgstr ""

#: ./doc/arch-design/storage_focus/section_architecture_storage_focus.xml:623(para)
msgid "OpenStack design, generally, does not include shared storage. However, for some high availability designs, certain components might require it depending on the specific implementation."
msgstr ""

#. When image changes, this message will be marked fuzzy or untranslated for you.
#. It doesn't matter what you translate it to: it's not used at all.
#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:194(None)
msgid "@@image: '../figures/Compute_Tech_Bin_Packing_General1.png'; md5=34f2f0b656a66124016d2484fb96068b"
msgstr ""

#. When image changes, this message will be marked fuzzy or untranslated for you.
#. It doesn't matter what you translate it to: it's not used at all.
#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:202(None)
msgid "@@image: '../figures/Compute_Tech_Bin_Packing_CPU_optimized1.png'; md5=45084140c29e59a459d6b0af9b47642a"
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:13(para)
msgid "In a compute-focused OpenStack cloud, the type of instance workloads you provision heavily influences technical decision making."
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:16(para)
msgid "Public and private clouds require deterministic capacity planning to support elastic growth in order to meet user SLA expectations. Deterministic capacity planning is the path to predicting the effort and expense of making a given process perform consistently. This process is important because, when a service becomes a critical part of a user's infrastructure, the user's experience links directly to the SLAs of the cloud itself."
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:24(para)
msgid "There are two aspects of capacity planning to consider:"
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:27(para)
msgid "Planning the initial deployment footprint"
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:30(para)
msgid "Planning expansion of the environment to stay ahead of the demands of cloud users"
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:34(para)
msgid "Begin planning an initial OpenStack deployment footprint with estimations of expected uptake, and existing infrastructure workloads."
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:36(para)
msgid "The starting point is the core count of the cloud. By applying relevant ratios, the user can gather information about:"
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:41(para)
msgid "The number of expected concurrent instances: (overcommit fraction × cores) / virtual cores per instance"
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:45(para)
msgid "Required storage: flavor disk size × number of instances"
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:48(para)
msgid "These ratios determine the amount of additional infrastructure needed to support the cloud. For example, consider a situation in which you require 1600 instances, each with 2 vCPU and 50 GB of storage. Assuming the default overcommit rate of 16:1, working out the math provides an equation of:"
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:56(para)
msgid "1600 = (16 (number of physical cores)) / 2"
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:59(para)
msgid "Storage required = 50GB 1600"
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:62(para)
msgid "On the surface, the equations reveal the need for 200 physical cores and 80TB of storage for /var/lib/nova/instances/. However, it is also important to look at patterns of usage to estimate the load that the API services, database servers, and queue servers are likely to encounter."
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:69(para)
msgid "Aside from the creation and termination of instances, consider the impact of users accessing the service, particularly on nova-api and its associated database. Listing instances gathers a great deal of information and given the frequency with which users run this operation, a cloud with a large number of users can increase the load significantly. This can even occur unintentionally. For example, the OpenStack Dashboard instances tab refreshes the list of instances every 30 seconds, so leaving it open in a browser window can cause unexpected load."
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:79(para)
msgid "Consideration of these factors can help determine how many cloud controller cores you require. A server with 8 CPU cores and 8 GB of RAM server would be sufficient for a rack of compute nodes, given the above caveats."
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:83(para)
msgid "Key hardware specifications are also crucial to the performance of user instances. Be sure to consider budget and performance needs, including storage performance (spindles/core), memory availability (RAM/core), network bandwidth (Gbps/core), and overall CPU performance (CPU/core)."
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:89(para)
msgid "The cloud resource calculator is a useful tool in examining the impacts of different hardware and instance load outs. See: <link xlink:href=\"https://github.com/noslzzp/cloud-resource-calculator/blob/master/cloud-resource-calculator.ods\">https://github.com/noslzzp/cloud-resource-calculator/blob/master/cloud-resource-calculator.ods</link>"
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:95(title)
msgid "Expansion planning"
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:96(para)
msgid "A key challenge for planning the expansion of cloud compute services is the elastic nature of cloud infrastructure demands."
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:99(para)
msgid "Planning for expansion is a balancing act. Planning too conservatively can lead to unexpected oversubscription of the cloud and dissatisfied users. Planning for cloud expansion too aggressively can lead to unexpected underutilization of the cloud and funds spent unnecessarily on operating infrastructure."
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:105(para)
msgid "The key is to carefully monitor the trends in cloud usage over time. The intent is to measure the consistency with which you deliver services, not the average speed or capacity of the cloud. Using this information to model capacity performance enables users to more accurately determine the current and future capacity of the cloud."
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:115(title)
msgid "CPU and RAM"
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:116(para)
msgid "OpenStack enables users to overcommit CPU and RAM on compute nodes. This allows an increase in the number of instances running on the cloud at the cost of reducing the performance of the instances. OpenStack Compute uses the following ratios by default:"
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:123(para)
msgid "CPU allocation ratio: 16:1"
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:126(para)
msgid "RAM allocation ratio: 1.5:1"
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:129(para)
msgid "The default CPU allocation ratio of 16:1 means that the scheduler allocates up to 16 virtual cores per physical core. For example, if a physical node has 12 cores, the scheduler sees 192 available virtual cores. With typical flavor definitions of 4 virtual cores per instance, this ratio would provide 48 instances on a physical node."
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:135(para)
msgid "Similarly, the default RAM allocation ratio of 1.5:1 means that the scheduler allocates instances to a physical node as long as the total amount of RAM associated with the instances is less than 1.5 times the amount of RAM available on the physical node."
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:140(para)
msgid "You must select the appropriate CPU and RAM allocation ratio based on particular use cases."
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:145(title)
msgid "Additional hardware"
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:146(para)
msgid "Certain use cases may benefit from exposure to additional devices on the compute node. Examples might include:"
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:150(para)
msgid "High performance computing jobs that benefit from the availability of graphics processing units (GPUs) for general-purpose computing."
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:155(para)
msgid "Cryptographic routines that benefit from the availability of hardware random number generators to avoid entropy starvation."
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:160(para)
msgid "Database management systems that benefit from the availability of SSDs for ephemeral storage to maximize read/write time."
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:165(para)
msgid "Host aggregates group hosts that share similar characteristics, which can include hardware similarities. The addition of specialized hardware to a cloud deployment is likely to add to the cost of each node, so consider carefully whether all compute nodes, or just a subset targeted by flavors, need the additional customization to support the desired workloads."
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:176(title) ./doc/arch-design/multi_site/section_tech_considerations_multi_site.xml:86(title) ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:80(title)
msgid "Utilization"
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:177(para)
msgid "Infrastructure-as-a-Service offerings, including OpenStack, use flavors to provide standardized views of virtual machine resource requirements that simplify the problem of scheduling instances while making the best use of the available physical resources."
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:182(para)
msgid "In order to facilitate packing of virtual machines onto physical hosts, the default selection of flavors provides a second largest flavor that is half the size of the largest flavor in every dimension. It has half the vCPUs, half the vRAM, and half the ephemeral disk space. The next largest flavor is half that size again. The following figure provides a visual representation of this concept for a general purpose computing design: <placeholder-1/>"
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:197(para)
msgid "The following figure displays a CPU-optimized, packed server: <placeholder-1/>"
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:205(para)
msgid "These default flavors are well suited to typical configurations of commodity server hardware. To maximize utilization, however, it may be necessary to customize the flavors or create new ones in order to better align instance sizes to the available hardware."
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:210(para)
msgid "Workload characteristics may also influence hardware choices and flavor configuration, particularly where they present different ratios of CPU versus RAM versus HDD requirements."
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:214(para)
msgid "For more information on Flavors see: <link xlink:href=\"http://docs.openstack.org/openstack-ops/content/flavors.html\">OpenStack Operations Guide: Flavors</link>"
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:220(para)
msgid "Due to the nature of the workloads in this scenario, a number of components are highly beneficial for a Compute-focused cloud. This includes the typical OpenStack components:"
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:226(para) ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:136(term)
msgid "OpenStack Compute (nova)"
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:235(para)
msgid "Also consider several specialized components:"
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:238(para)
msgid "<glossterm>Orchestration</glossterm> (heat)"
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:239(para)
msgid "Given the nature of the applications involved in this scenario, these are heavily automated deployments. Making use of Orchestration is highly beneficial in this case. You can script the deployment of a batch of instances and the running of tests, but it makes sense to use the Orchestration service to handle all these actions."
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:248(para) ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:153(term)
msgid "Telemetry (ceilometer)"
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:249(para)
msgid "Telemetry and the alarms it generates support autoscaling of instances using Orchestration. Users that are not using the Orchestration service do not need to deploy the Telemetry service and may choose to use external solutions to fulfill their metering and monitoring requirements."
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:257(para)
msgid "Due to the burst-able nature of the workloads and the applications and instances that perform batch processing, this cloud mainly uses memory or CPU, so the need for add-on storage to each instance is not a likely requirement. This does not mean that you do not use OpenStack Block Storage (cinder) in the infrastructure, but typically it is not a central component."
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:266(para) ./doc/arch-design/multi_site/section_architecture_multi_site.xml:89(title)
msgid "Networking"
msgstr ""

#: ./doc/arch-design/compute_focus/section_tech_considerations_compute_focus.xml:267(para)
msgid "When choosing a networking platform, ensure that it either works with all desired hypervisor and container technologies and their OpenStack drivers, or that it includes an implementation of an ML2 mechanism driver. You can mix networking platforms that provide ML2 mechanisms drivers."
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:9(para)
msgid "The hardware selection covers three areas:"
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:12(para) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:16(para) ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:17(para)
msgid "Compute"
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:15(para) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:19(para) ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:22(para)
msgid "Network"
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:18(para) ./doc/arch-design/multi_site/section_architecture_multi_site.xml:57(title) ./doc/arch-design/multi_site/section_user_requirements_multi_site.xml:114(para) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:22(para) ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:27(para)
msgid "Storage"
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:21(para)
msgid "Compute-focused OpenStack clouds have high demands on processor and memory resources, and requires hardware that can handle these demands. Consider the following factors when selecting compute (server) hardware:"
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:38(para)
msgid "Weigh these considerations against each other to determine the best design for the desired purpose. For example, increasing server density means sacrificing resource capacity or expandability."
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:41(para)
msgid "A compute-focused cloud should have an emphasis on server hardware that can offer more CPU sockets, more CPU cores, and more RAM. Network connectivity and storage capacity are less critical."
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:44(para)
msgid "When designing a compute-focused OpenStack architecture, you must consider whether you intend to scale up or scale out. Selecting a smaller number of larger hosts, or a larger number of smaller hosts, depends on a combination of factors: cost, power, cooling, physical rack and floor space, support-warranty, and manageability."
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:50(para)
msgid "Considerations for selecting hardware:"
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:53(para)
msgid "Most blade servers can support dual-socket multi-core CPUs. To avoid this CPU limit, select <literal>full width</literal> or <literal>full height</literal> blades. Be aware, however, that this also decreases server density. For example, high density blade servers such as HP BladeSystem or Dell PowerEdge M1000e support up to 16 servers in only ten rack units. Using half-height blades is twice as dense as using full-height blades, which results in only eight servers per ten rack units."
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:63(para)
msgid "1U rack-mounted servers that occupy only a single rack unit may offer greater server density than a blade server solution. It is possible to place forty 1U servers in a rack, providing space for the top of rack (ToR) switches, compared to 32 full width blade servers."
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:70(para)
msgid "2U rack-mounted servers provide quad-socket, multi-core CPU support, but with a corresponding decrease in server density (half the density that 1U rack-mounted servers offer)."
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:75(para)
msgid "Larger rack-mounted servers, such as 4U servers, often provide even greater CPU capacity, commonly supporting four or even eight CPU sockets. These servers have greater expandability, but such servers have much lower server density and are often more expensive."
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:81(para)
msgid "<literal>Sled servers</literal> are rack-mounted servers that support multiple independent servers in a single 2U or 3U enclosure. These deliver higher density as compared to typical 1U or 2U rack-mounted servers. For example, many sled servers offer four independent dual-socket nodes in 2U for a total of eight CPU sockets in 2U."
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:89(para)
msgid "Consider these when choosing server hardware for a compute- focused OpenStack design architecture:"
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:104(title) ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:382(title)
msgid "Selecting networking hardware"
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:105(para)
msgid "Some of the key considerations for networking hardware selection include:"
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:124(para)
msgid "We recommend designing the network architecture using a scalable network model that makes it easy to add capacity and bandwidth. A good example of such a model is the leaf-spline model. In this type of network design, it is possible to easily add additional bandwidth as well as scale out to additional racks of gear. It is important to select network hardware that supports the required port count, port speed, and port density while also allowing for future growth as workload demands increase. It is also important to evaluate where in the network architecture it is valuable to provide redundancy."
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:137(para)
msgid "The selection of operating system (OS) and hypervisor has a significant impact on the end point design."
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:139(para)
msgid "OS and hypervisor selection impact the following areas:"
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:167(para)
msgid "The selection of OpenStack components is important. There are certain components that are required, for example the compute and image services, but others, such as the Orchestration service, may not be present."
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:171(para)
msgid "For a compute-focused OpenStack design architecture, the following components may be present:"
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:175(para)
msgid "Identity (keystone)"
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:178(para)
msgid "Dashboard (horizon)"
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:181(para)
msgid "Compute (nova)"
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:184(para)
msgid "Object Storage (swift)"
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:187(para)
msgid "Image (glance)"
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:190(para) ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:144(term)
msgid "Networking (neutron)"
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:193(para) ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:160(term)
msgid "Orchestration (heat)"
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:197(para)
msgid "A compute-focused design is less likely to include OpenStack Block Storage. However, there may be some situations where the need for performance requires a block storage component to improve data I-O."
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:201(para)
msgid "The exclusion of certain OpenStack components might also limit the functionality of other components. If a design includes the Orchestration service but excludes the Telemetry service, then the design cannot take advantage of Orchestration's auto scaling functionality as this relies on information from Telemetry."
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:210(para)
msgid "OpenStack Networking provides a wide variety of networking services for instances. There are many additional networking software packages that might be useful to manage the OpenStack components themselves. The <citetitle>OpenStack High Availability Guide</citetitle> (<link xlink:href=\"http://docs.openstack.org/ha-guide/\">http://docs.openstack.org/ha-guide/</link>) describes some of these software packages in more detail."
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:217(para)
msgid "For a compute-focused OpenStack cloud, the OpenStack infrastructure components must be highly available. If the design does not include hardware load balancing, you must add networking software packages, for example, HAProxy."
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:225(para)
msgid "The selected supplemental software solution impacts and affects the overall OpenStack cloud design. This includes software for providing clustering, logging, monitoring and alerting."
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:228(para)
msgid "The availability of design requirements is the main determiner for the inclusion of clustering software, such as Corosync or Pacemaker."
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:230(para)
msgid "Operational considerations determine the requirements for logging, monitoring, and alerting. Each of these sub-categories include various options."
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:233(para)
msgid "Some other potential design impacts include:"
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:236(term)
msgid "OS-hypervisor combination"
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:238(para)
msgid "Ensure that the selected logging, monitoring, or alerting tools support the proposed OS-hypervisor combination."
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:244(term)
msgid "Network hardware"
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:246(para)
msgid "The logging, monitoring, and alerting software must support the network hardware selection."
msgstr ""

#: ./doc/arch-design/compute_focus/section_architecture_compute_focus.xml:255(para)
msgid "A large majority of OpenStack components require access to back-end database services to store state and configuration information. Select an appropriate back-end database that satisfies the availability and fault tolerance requirements of the OpenStack services. OpenStack services support connecting to any database that the SQLAlchemy Python drivers support, however most common database deployments make use of MySQL or some variation of it. We recommend that you make the database that provides back-end services within a general-purpose cloud highly available. Some of the more common software solutions include Galera, MariaDB, and MySQL with multi-master replication."
msgstr ""

#. When image changes, this message will be marked fuzzy or untranslated for you.
#. It doesn't matter what you translate it to: it's not used at all.
#: ./doc/arch-design/compute_focus/section_prescriptive_examples_compute_focus.xml:78(None)
msgid "@@image: '../figures/Generic_CERN_Example.png'; md5=268e2171493d49ff3cc791071a98b49e"
msgstr ""

#. When image changes, this message will be marked fuzzy or untranslated for you.
#. It doesn't matter what you translate it to: it's not used at all.
#: ./doc/arch-design/compute_focus/section_prescriptive_examples_compute_focus.xml:148(None)
msgid "@@image: '../figures/Generic_CERN_Architecture.png'; md5=f5ec57432a0b3bd35efeaa25e84d9947"
msgstr ""

#: ./doc/arch-design/compute_focus/section_prescriptive_examples_compute_focus.xml:9(para)
msgid "The Conseil Européen pour la Recherche Nucléaire (CERN), also known as the European Organization for Nuclear Research, provides particle accelerators and other infrastructure for high-energy physics research."
msgstr ""

#: ./doc/arch-design/compute_focus/section_prescriptive_examples_compute_focus.xml:13(para)
msgid "As of 2011 CERN operated these two compute centers in Europe with plans to add a third."
msgstr ""

#: ./doc/arch-design/compute_focus/section_prescriptive_examples_compute_focus.xml:19(th)
msgid "Data center"
msgstr ""

#: ./doc/arch-design/compute_focus/section_prescriptive_examples_compute_focus.xml:19(th)
msgid "Approximate capacity"
msgstr ""

#: ./doc/arch-design/compute_focus/section_prescriptive_examples_compute_focus.xml:23(td)
msgid "Geneva, Switzerland"
msgstr ""

#: ./doc/arch-design/compute_focus/section_prescriptive_examples_compute_focus.xml:26(para)
msgid "3.5 Mega Watts"
msgstr ""

#: ./doc/arch-design/compute_focus/section_prescriptive_examples_compute_focus.xml:27(para)
msgid "91000 cores"
msgstr ""

#: ./doc/arch-design/compute_focus/section_prescriptive_examples_compute_focus.xml:28(para)
msgid "120 PB HDD"
msgstr ""

#: ./doc/arch-design/compute_focus/section_prescriptive_examples_compute_focus.xml:29(para)
msgid "100 PB Tape"
msgstr ""

#: ./doc/arch-design/compute_focus/section_prescriptive_examples_compute_focus.xml:30(para)
msgid "310 TB Memory"
msgstr ""

#: ./doc/arch-design/compute_focus/section_prescriptive_examples_compute_focus.xml:35(td)
msgid "Budapest, Hungary"
msgstr ""

#: ./doc/arch-design/compute_focus/section_prescriptive_examples_compute_focus.xml:38(para)
msgid "2.5 Mega Watts"
msgstr ""

#: ./doc/arch-design/compute_focus/section_prescriptive_examples_compute_focus.xml:39(para)
msgid "20000 cores"
msgstr ""

#: ./doc/arch-design/compute_focus/section_prescriptive_examples_compute_focus.xml:40(para)
msgid "6 PB HDD"
msgstr ""

#: ./doc/arch-design/compute_focus/section_prescriptive_examples_compute_focus.xml:46(para)
msgid "To support a growing number of compute-heavy users of experiments related to the Large Hadron Collider (LHC), CERN ultimately elected to deploy an OpenStack cloud using Scientific Linux and RDO. This effort aimed to simplify the management of the center's compute resources with a view to doubling compute capacity through the addition of a data center in 2013 while maintaining the same levels of compute staff."
msgstr ""

#: ./doc/arch-design/compute_focus/section_prescriptive_examples_compute_focus.xml:54(para)
msgid "The CERN solution uses <glossterm baseform=\"cell\">cells</glossterm> for segregation of compute resources and for transparently scaling between different data centers. This decision meant trading off support for security groups and live migration. In addition, they must manually replicate some details, like flavors, across cells. In spite of these drawbacks cells provide the required scale while exposing a single public API endpoint to users."
msgstr ""

#: ./doc/arch-design/compute_focus/section_prescriptive_examples_compute_focus.xml:63(para)
msgid "CERN created a compute cell for each of the two original data centers and created a third when it added a new data center in 2013. Each cell contains three availability zones to further segregate compute resources and at least three RabbitMQ message brokers configured for clustering with mirrored queues for high availability."
msgstr ""

#: ./doc/arch-design/compute_focus/section_prescriptive_examples_compute_focus.xml:69(para)
msgid "The API cell, which resides behind a HAProxy load balancer, is in the data center in Switzerland and directs API calls to compute cells using a customized variation of the cell scheduler. The customizations allow certain workloads to route to a specific data center or all data centers, with cell RAM availability determining cell selection in the latter case."
msgstr ""

#: ./doc/arch-design/compute_focus/section_prescriptive_examples_compute_focus.xml:81(para)
msgid "There is also some customization of the filter scheduler that handles placement within the cells:"
msgstr ""

#: ./doc/arch-design/compute_focus/section_prescriptive_examples_compute_focus.xml:84(term)
msgid "ImagePropertiesFilter"
msgstr ""

#: ./doc/arch-design/compute_focus/section_prescriptive_examples_compute_focus.xml:86(para)
msgid "Provides special handling depending on the guest operating system in use (Linux-based or Windows-based)."
msgstr ""

#: ./doc/arch-design/compute_focus/section_prescriptive_examples_compute_focus.xml:91(term)
msgid "ProjectsToAggregateFilter"
msgstr ""

#: ./doc/arch-design/compute_focus/section_prescriptive_examples_compute_focus.xml:92(para)
msgid "Provides special handling depending on which project the instance is associated with."
msgstr ""

#: ./doc/arch-design/compute_focus/section_prescriptive_examples_compute_focus.xml:97(term)
msgid "default_schedule_zones"
msgstr ""

#: ./doc/arch-design/compute_focus/section_prescriptive_examples_compute_focus.xml:98(para)
msgid "Allows the selection of multiple default availability zones, rather than a single default."
msgstr ""

#: ./doc/arch-design/compute_focus/section_prescriptive_examples_compute_focus.xml:104(para)
msgid "A central database team manages the MySQL database server in each cell in an active/passive configuration with a NetApp storage back end. Backups run every 6 hours."
msgstr ""

#: ./doc/arch-design/compute_focus/section_prescriptive_examples_compute_focus.xml:109(title)
msgid "Network architecture"
msgstr ""

#: ./doc/arch-design/compute_focus/section_prescriptive_examples_compute_focus.xml:110(para)
msgid "To integrate with existing networking infrastructure, CERN made customizations to legacy networking (nova-network). This was in the form of a driver to integrate with CERN's existing database for tracking MAC and IP address assignments."
msgstr ""

#: ./doc/arch-design/compute_focus/section_prescriptive_examples_compute_focus.xml:114(para)
msgid "The driver facilitates selection of a MAC address and IP for new instances based on the compute node where the scheduler places the instance."
msgstr ""

#: ./doc/arch-design/compute_focus/section_prescriptive_examples_compute_focus.xml:117(para)
msgid "The driver considers the compute node where the scheduler placed an instance and selects a MAC address and IP from the pre-registered list associated with that node in the database. The database updates to reflect the address assignment to that instance."
msgstr ""

#: ./doc/arch-design/compute_focus/section_prescriptive_examples_compute_focus.xml:125(title)
msgid "Storage architecture"
msgstr ""

#: ./doc/arch-design/compute_focus/section_prescriptive_examples_compute_focus.xml:126(para)
msgid "CERN deploys the OpenStack Image service in the API cell and configures it to expose version 1 (V1) of the API. This also requires the image registry. The storage back end in use is a 3 PB Ceph cluster."
msgstr ""

#: ./doc/arch-design/compute_focus/section_prescriptive_examples_compute_focus.xml:130(para)
msgid "CERN maintains a small set of Scientific Linux 5 and 6 images onto which orchestration tools can place applications. Puppet manages instance configuration and customization."
msgstr ""

#: ./doc/arch-design/compute_focus/section_prescriptive_examples_compute_focus.xml:137(para)
msgid "CERN does not require direct billing, but uses the Telemetry service to perform metering for the purposes of adjusting project quotas. CERN uses a sharded, replicated, MongoDB back-end. To spread API load, CERN deploys instances of the nova-api service within the child cells for Telemetry to query against. This also requires the configuration of supporting services such as keystone, glance-api, and glance-registry in the child cells."
msgstr ""

#: ./doc/arch-design/compute_focus/section_prescriptive_examples_compute_focus.xml:151(para)
msgid "Additional monitoring tools in use include <link xlink:href=\"http://flume.apache.org/\">Flume</link>, <link xlink:href=\"http://www.elasticsearch.org/\">Elastic Search</link>, <link xlink:href=\"http://www.elasticsearch.org/overview/kibana/\">Kibana</link>, and the CERN developed <link xlink:href=\"http://lemon.web.cern.ch/lemon/index.shtml\">Lemon</link> project."
msgstr ""

#: ./doc/arch-design/compute_focus/section_operational_considerations_compute_focus.xml:9(para)
msgid "There are a number of operational considerations that affect the design of compute-focused OpenStack clouds, including:"
msgstr ""

#: ./doc/arch-design/compute_focus/section_operational_considerations_compute_focus.xml:13(para)
msgid "Enforcing strict API availability requirements"
msgstr ""

#: ./doc/arch-design/compute_focus/section_operational_considerations_compute_focus.xml:18(para)
msgid "Understanding and dealing with failure scenarios"
msgstr ""

#: ./doc/arch-design/compute_focus/section_operational_considerations_compute_focus.xml:23(para)
msgid "Managing host maintenance schedules"
msgstr ""

#: ./doc/arch-design/compute_focus/section_operational_considerations_compute_focus.xml:28(para)
msgid "Service-level agreements (SLAs) are contractual obligations that ensure the availability of a service. When designing an OpenStack cloud, factoring in promises of availability implies a certain level of redundancy and resiliency."
msgstr ""

#: ./doc/arch-design/compute_focus/section_operational_considerations_compute_focus.xml:35(para)
msgid "OpenStack clouds require appropriate monitoring platforms to catch and manage errors."
msgstr ""

#: ./doc/arch-design/compute_focus/section_operational_considerations_compute_focus.xml:38(para)
msgid "We recommend leveraging existing monitoring systems to see if they are able to effectively monitor an OpenStack environment."
msgstr ""

#: ./doc/arch-design/compute_focus/section_operational_considerations_compute_focus.xml:42(para)
msgid "Specific meters that are critically important to capture include:"
msgstr ""

#: ./doc/arch-design/compute_focus/section_operational_considerations_compute_focus.xml:46(para) ./doc/arch-design/generalpurpose/section_operational_considerations_general_purpose.xml:62(para)
msgid "Image disk utilization"
msgstr ""

#: ./doc/arch-design/compute_focus/section_operational_considerations_compute_focus.xml:49(para) ./doc/arch-design/generalpurpose/section_operational_considerations_general_purpose.xml:67(para)
msgid "Response time to the Compute API"
msgstr ""

#: ./doc/arch-design/compute_focus/section_operational_considerations_compute_focus.xml:56(para)
msgid "Adding extra capacity to an OpenStack cloud is a horizontally scaling process."
msgstr ""

#: ./doc/arch-design/compute_focus/section_operational_considerations_compute_focus.xml:58(para)
msgid "We recommend similar (or the same) CPUs when adding extra nodes to the environment. This reduces the chance of breaking live-migration features if they are present. Scaling out hypervisor hosts also has a direct effect on network and other data center resources. We recommend you factor in this increase when reaching rack capacity or when requiring extra network switches."
msgstr ""

#: ./doc/arch-design/compute_focus/section_operational_considerations_compute_focus.xml:65(para)
msgid "Changing the internal components of a Compute host to account for increases in demand is a process known as vertical scaling. Swapping a CPU for one with more cores, or increasing the memory in a server, can help add extra capacity for running applications."
msgstr ""

#: ./doc/arch-design/compute_focus/section_operational_considerations_compute_focus.xml:70(para)
msgid "Another option is to assess the average workloads and increase the number of instances that can run within the compute environment by adjusting the overcommit ratio."
msgstr ""

#: ./doc/arch-design/compute_focus/section_operational_considerations_compute_focus.xml:74(para)
msgid "It is important to remember that changing the CPU overcommit ratio can have a detrimental effect and cause a potential increase in a noisy neighbor."
msgstr ""

#: ./doc/arch-design/compute_focus/section_operational_considerations_compute_focus.xml:78(para)
msgid "The added risk of increasing the overcommit ratio is that more instances fail when a compute host fails. We do not recommend that you increase the CPU overcommit ratio in compute-focused OpenStack design architecture, as it can increase the potential for noisy neighbor issues."
msgstr ""

#: ./doc/arch-design/multi_site/section_operational_considerations_multi_site.xml:9(para)
msgid "Multi-site OpenStack cloud deployment using regions requires that the service catalog contains per-region entries for each service deployed other than the Identity service. Most off-the-shelf OpenStack deployment tools have limited support for defining multiple regions in this fashion."
msgstr ""

#: ./doc/arch-design/multi_site/section_operational_considerations_multi_site.xml:14(para)
msgid "Deployers should be aware of this and provide the appropriate customization of the service catalog for their site either manually, or by customizing deployment tools in use."
msgstr ""

#: ./doc/arch-design/multi_site/section_operational_considerations_multi_site.xml:17(para)
msgid "As of the Kilo release, documentation for implementing this feature is in progress. See this bug for more information: <link xlink:href=\"https://bugs.launchpad.net/openstack-manuals/+bug/1340509\">https://bugs.launchpad.net/openstack-manuals/+bug/1340509</link>."
msgstr ""

#: ./doc/arch-design/multi_site/section_operational_considerations_multi_site.xml:24(title)
msgid "Licensing"
msgstr ""

#: ./doc/arch-design/multi_site/section_operational_considerations_multi_site.xml:25(para)
msgid "Multi-site OpenStack deployments present additional licensing considerations over and above regular OpenStack clouds, particularly where site licenses are in use to provide cost efficient access to software licenses. The licensing for host operating systems, guest operating systems, OpenStack distributions (if applicable), software-defined infrastructure including network controllers and storage systems, and even individual applications need to be evaluated."
msgstr ""

#: ./doc/arch-design/multi_site/section_operational_considerations_multi_site.xml:33(para)
msgid "Topics to consider include:"
msgstr ""

#: ./doc/arch-design/multi_site/section_operational_considerations_multi_site.xml:36(para)
msgid "The definition of what constitutes a site in the relevant licenses, as the term does not necessarily denote a geographic or otherwise physically isolated location."
msgstr ""

#: ./doc/arch-design/multi_site/section_operational_considerations_multi_site.xml:42(para)
msgid "Differentiations between \"hot\" (active) and \"cold\" (inactive) sites, where significant savings may be made in situations where one site is a cold standby for disaster recovery purposes only."
msgstr ""

#: ./doc/arch-design/multi_site/section_operational_considerations_multi_site.xml:48(para)
msgid "Certain locations might require local vendors to provide support and services for each site which may vary with the licensing agreement in place."
msgstr ""

#: ./doc/arch-design/multi_site/section_operational_considerations_multi_site.xml:54(title)
msgid "Logging and monitoring"
msgstr ""

#: ./doc/arch-design/multi_site/section_operational_considerations_multi_site.xml:55(para)
msgid "Logging and monitoring does not significantly differ for a multi-site OpenStack cloud. The tools described in the <link xlink:href=\"http://docs.openstack.org/openstack-ops/content/logging_monitoring.html\">Logging and monitoring chapter</link> of the <citetitle>Operations Guide</citetitle> remain applicable. Logging and monitoring can be provided on a per-site basis, and in a common centralized location."
msgstr ""

#: ./doc/arch-design/multi_site/section_operational_considerations_multi_site.xml:62(para)
msgid "When attempting to deploy logging and monitoring facilities to a centralized location, care must be taken with the load placed on the inter-site networking links."
msgstr ""

#: ./doc/arch-design/multi_site/section_operational_considerations_multi_site.xml:66(title) ./doc/arch-design/hybrid/section_operational_considerations_hybrid.xml:44(title)
msgid "Upgrades"
msgstr ""

#: ./doc/arch-design/multi_site/section_operational_considerations_multi_site.xml:67(para)
msgid "In multi-site OpenStack clouds deployed using regions, sites are independent OpenStack installations which are linked together using shared centralized services such as OpenStack Identity. At a high level the recommended order of operations to upgrade an individual OpenStack environment is (see the <link xlink:href=\"http://docs.openstack.org/openstack-ops/content/ops_upgrades-general-steps.html\">Upgrades chapter</link> of the <citetitle>Operations Guide</citetitle> for details):"
msgstr ""

#: ./doc/arch-design/multi_site/section_operational_considerations_multi_site.xml:77(para)
msgid "Upgrade the OpenStack Identity service (keystone)."
msgstr ""

#: ./doc/arch-design/multi_site/section_operational_considerations_multi_site.xml:81(para)
msgid "Upgrade the OpenStack Image service (glance)."
msgstr ""

#: ./doc/arch-design/multi_site/section_operational_considerations_multi_site.xml:84(para)
msgid "Upgrade OpenStack Compute (nova), including networking components."
msgstr ""

#: ./doc/arch-design/multi_site/section_operational_considerations_multi_site.xml:88(para)
msgid "Upgrade OpenStack Block Storage (cinder)."
msgstr ""

#: ./doc/arch-design/multi_site/section_operational_considerations_multi_site.xml:91(para)
msgid "Upgrade the OpenStack dashboard (horizon)."
msgstr ""

#: ./doc/arch-design/multi_site/section_operational_considerations_multi_site.xml:94(para)
msgid "The process for upgrading a multi-site environment is not significantly different:"
msgstr ""

#: ./doc/arch-design/multi_site/section_operational_considerations_multi_site.xml:98(para)
msgid "Upgrade the shared OpenStack Identity service (keystone) deployment."
msgstr ""

#: ./doc/arch-design/multi_site/section_operational_considerations_multi_site.xml:102(para)
msgid "Upgrade the OpenStack Image service (glance) at each site."
msgstr ""

#: ./doc/arch-design/multi_site/section_operational_considerations_multi_site.xml:106(para)
msgid "Upgrade OpenStack Compute (nova), including networking components, at each site."
msgstr ""

#: ./doc/arch-design/multi_site/section_operational_considerations_multi_site.xml:110(para)
msgid "Upgrade OpenStack Block Storage (cinder) at each site."
msgstr ""

#: ./doc/arch-design/multi_site/section_operational_considerations_multi_site.xml:114(para)
msgid "Upgrade the OpenStack dashboard (horizon), at each site or in the single central location if it is shared."
msgstr ""

#: ./doc/arch-design/multi_site/section_operational_considerations_multi_site.xml:119(para)
msgid "Compute upgrades within each site can also be performed in a rolling fashion. Compute controller services (API, Scheduler, and Conductor) can be upgraded prior to upgrading of individual compute nodes. This allows operations staff to keep a site operational for users of Compute services while performing an upgrade."
msgstr ""

#: ./doc/arch-design/multi_site/section_operational_considerations_multi_site.xml:126(title)
msgid "Quota management"
msgstr ""

#: ./doc/arch-design/multi_site/section_operational_considerations_multi_site.xml:127(para)
msgid "Quotas are used to set operational limits to prevent system capacities from being exhausted without notification. They are currently enforced at the tenant (or project) level rather than at the user level."
msgstr ""

#: ./doc/arch-design/multi_site/section_operational_considerations_multi_site.xml:131(para)
msgid "Quotas are defined on a per-region basis. Operators can define identical quotas for tenants in each region of the cloud to provide a consistent experience, or even create a process for synchronizing allocated quotas across regions. It is important to note that only the operational limits imposed by the quotas will be aligned consumption of quotas by users will not be reflected between regions."
msgstr ""

#: ./doc/arch-design/multi_site/section_operational_considerations_multi_site.xml:138(para)
msgid "For example, given a cloud with two regions, if the operator grants a user a quota of 25 instances in each region then that user may launch a total of 50 instances spread across both regions. They may not, however, launch more than 25 instances in any single region."
msgstr ""

#: ./doc/arch-design/multi_site/section_operational_considerations_multi_site.xml:143(para)
msgid "For more information on managing quotas refer to the <link xlink:href=\"http://docs.openstack.org/openstack-ops/content/projects_users.html\">Managing projects and users chapter</link> of the <citetitle>OpenStack Operators Guide</citetitle>."
msgstr ""

#: ./doc/arch-design/multi_site/section_operational_considerations_multi_site.xml:150(title)
msgid "Policy management"
msgstr ""

#: ./doc/arch-design/multi_site/section_operational_considerations_multi_site.xml:151(para)
msgid "OpenStack provides a default set of Role Based Access Control (RBAC) policies, defined in a <filename>policy.json</filename> file, for each service. Operators edit these files to customize the policies for their OpenStack installation. If the application of consistent RBAC policies across sites is a requirement, then it is necessary to ensure proper synchronization of the <filename>policy.json</filename> files to all installations."
msgstr ""

#: ./doc/arch-design/multi_site/section_operational_considerations_multi_site.xml:158(para)
msgid "This must be done using system administration tools such as rsync as functionality for synchronizing policies across regions is not currently provided within OpenStack."
msgstr ""

#: ./doc/arch-design/multi_site/section_operational_considerations_multi_site.xml:162(title)
msgid "Documentation"
msgstr ""

#: ./doc/arch-design/multi_site/section_operational_considerations_multi_site.xml:163(para)
msgid "Users must be able to leverage cloud infrastructure and provision new resources in the environment. It is important that user documentation is accessible by users to ensure they are given sufficient information to help them leverage the cloud. As an example, by default OpenStack schedules instances on a compute node automatically. However, when multiple regions are available, the end user needs to decide in which region to schedule the new instance. The dashboard presents the user with the first region in your configuration. The API and CLI tools do not execute commands unless a valid region is specified. It is therefore important to provide documentation to your users describing the region layout as well as calling out that quotas are region-specific. If a user reaches his or her quota in one region, OpenStack does not automatically build new instances in another. Documenting specific examples helps users understand how to operate the cloud, thereby reducing calls and tickets filed with the help desk."
msgstr ""

#. When image changes, this message will be marked fuzzy or untranslated for you.
#. It doesn't matter what you translate it to: it's not used at all.
#: ./doc/arch-design/multi_site/section_architecture_multi_site.xml:24(None)
msgid "@@image: '../figures/Multi-Site_shared_keystone_horizon_swift1.png'; md5=fb80511b491731906fb54d5a1f029f91"
msgstr ""

#: ./doc/arch-design/multi_site/section_architecture_multi_site.xml:9(para)
msgid "<xref linkend=\"multi-site_arch\"/> illustrates a high level multi-site OpenStack architecture. Each site is an OpenStack cloud but it may be necessary to architect the sites on different versions. For example, if the second site is intended to be a replacement for the first site, they would be different. Another common design would be a private OpenStack cloud with a replicated site that would be used for high availability or disaster recovery. The most important design decision is configuring storage as a single shared pool or separate pools, depending on user and technical requirements."
msgstr ""

#: ./doc/arch-design/multi_site/section_architecture_multi_site.xml:20(title)
msgid "Multi-site OpenStack architecture"
msgstr ""

#: ./doc/arch-design/multi_site/section_architecture_multi_site.xml:29(title)
msgid "OpenStack services architecture"
msgstr ""

#: ./doc/arch-design/multi_site/section_architecture_multi_site.xml:30(para)
msgid "The Identity service, which is used by all other OpenStack components for authorization and the catalog of service endpoints, supports the concept of regions. A region is a logical construct used to group OpenStack services in close proximity to one another. The concept of regions is flexible; it may contain OpenStack service endpoints located within a distinct geographic region or regions. It may be smaller in scope, where a region is a single rack within a data center, with multiple regions existing in adjacent racks in the same data center."
msgstr ""

#: ./doc/arch-design/multi_site/section_architecture_multi_site.xml:40(para)
msgid "The majority of OpenStack components are designed to run within the context of a single region. The Compute service is designed to manage compute resources within a region, with support for subdivisions of compute resources by using availability zones and cells. The Networking service can be used to manage network resources in the same broadcast domain or collection of switches that are linked. The OpenStack Block Storage service controls storage resources within a region with all storage resources residing on the same storage network. Like the OpenStack Compute service, the OpenStack Block Storage service also supports the availability zone construct which can be used to subdivide storage resources."
msgstr ""

#: ./doc/arch-design/multi_site/section_architecture_multi_site.xml:52(para)
msgid "The OpenStack dashboard, OpenStack Identity, and OpenStack Object Storage services are components that can each be deployed centrally in order to serve multiple regions."
msgstr ""

#: ./doc/arch-design/multi_site/section_architecture_multi_site.xml:58(para)
msgid "With multiple OpenStack regions, it is recommended to configure a single OpenStack Object Storage service endpoint to deliver shared file storage for all regions. The Object Storage service internally replicates files to multiple nodes which can be used by applications or workloads in multiple regions. This simplifies high availability failover and disaster recovery rollback."
msgstr ""

#: ./doc/arch-design/multi_site/section_architecture_multi_site.xml:64(para)
msgid "In order to scale the Object Storage service to meet the workload of multiple regions, multiple proxy workers are run and load-balanced, storage nodes are installed in each region, and the entire Object Storage Service can be fronted by an HTTP caching layer. This is done so client requests for objects can be served out of caches rather than directly from the storage modules themselves, reducing the actual load on the storage network. In addition to an HTTP caching layer, use a caching layer like Memcache to cache objects between the proxy and storage nodes."
msgstr ""

#: ./doc/arch-design/multi_site/section_architecture_multi_site.xml:73(para)
msgid "If the cloud is designed with a separate Object Storage service endpoint made available in each region, applications are required to handle synchronization (if desired) and other management operations to ensure consistency across the nodes. For some applications, having multiple Object Storage Service endpoints located in the same region as the application may be desirable due to reduced latency, cross region bandwidth, and ease of deployment."
msgstr ""

#: ./doc/arch-design/multi_site/section_architecture_multi_site.xml:82(para)
msgid "For the Block Storage service, the most important decisions are the selection of the storage technology, and whether a dedicated network is used to carry storage traffic from the storage service to the compute nodes."
msgstr ""

#: ./doc/arch-design/multi_site/section_architecture_multi_site.xml:90(para)
msgid "When connecting multiple regions together, there are several design considerations. The overlay network technology choice determines how packets are transmitted between regions and how the logical network and addresses present to the application. If there are security or regulatory requirements, encryption should be implemented to secure the traffic between regions. For networking inside a region, the overlay network technology for tenant networks is equally important. The overlay technology and the network traffic that an application generates or receives can be either complementary or serve cross purposes. For example, using an overlay technology for an application that transmits a large amount of small packets could add excessive latency or overhead to each packet if not configured properly."
msgstr ""

#: ./doc/arch-design/multi_site/section_architecture_multi_site.xml:105(title) ./doc/arch-design/introduction/section_methodology.xml:86(term)
msgid "Dependencies"
msgstr ""

#: ./doc/arch-design/multi_site/section_architecture_multi_site.xml:106(para)
msgid "The architecture for a multi-site OpenStack installation is dependent on a number of factors. One major dependency to consider is storage. When designing the storage system, the storage mechanism needs to be determined. Once the storage type is determined, how it is accessed is critical. For example, we recommend that storage should use a dedicated network. Another concern is how the storage is configured to protect the data. For example, the Recovery Point Objective (RPO) and the Recovery Time Objective (RTO). How quickly recovery from a fault can be completed, determines how often the replication of data is required. Ensure that enough storage is allocated to support the data protection strategy."
msgstr ""

#: ./doc/arch-design/multi_site/section_architecture_multi_site.xml:119(para)
msgid "Networking decisions include the encapsulation mechanism that can be used for the tenant networks, how large the broadcast domains should be, and the contracted SLAs for the interconnects."
msgstr ""

#: ./doc/arch-design/multi_site/section_tech_considerations_multi_site.xml:9(para)
msgid "There are many technical considerations to take into account with regard to designing a multi-site OpenStack implementation. An OpenStack cloud can be designed in a variety of ways to handle individual application needs. A multi-site deployment has additional challenges compared to single site installations and therefore is a more complex solution."
msgstr ""

#: ./doc/arch-design/multi_site/section_tech_considerations_multi_site.xml:16(para)
msgid "When determining capacity options be sure to take into account not just the technical issues, but also the economic or operational issues that might arise from specific decisions."
msgstr ""

#: ./doc/arch-design/multi_site/section_tech_considerations_multi_site.xml:20(para)
msgid "Inter-site link capacity describes the capabilities of the connectivity between the different OpenStack sites. This includes parameters such as bandwidth, latency, whether or not a link is dedicated, and any business policies applied to the connection. The capability and number of the links between sites determine what kind of options are available for deployment. For example, if two sites have a pair of high-bandwidth links available between them, it may be wise to configure a separate storage replication network between the two sites to support a single Swift endpoint and a shared Object Storage capability between them. An example of this technique, as well as a configuration walk-through, is available at <link xlink:href=\"http://docs.openstack.org/developer/swift/replication_network.html#dedicated-replication-network\">http://docs.openstack.org/developer/swift/replication_network.html#dedicated-replication-network</link>. Another option in this scenario is to build a dedicated set of tenant private networks across the secondary link, using overlay networks with a third party mapping the site overlays to each other."
msgstr ""

#: ./doc/arch-design/multi_site/section_tech_considerations_multi_site.xml:38(para)
msgid "The capacity requirements of the links between sites is driven by application behavior. If the link latency is too high, certain applications that use a large number of small packets, for example RPC calls, may encounter issues communicating with each other or operating properly. Additionally, OpenStack may encounter similar types of issues. To mitigate this, Identity service call timeouts can be tuned to prevent issues authenticating against a central Identity service."
msgstr ""

#: ./doc/arch-design/multi_site/section_tech_considerations_multi_site.xml:47(para)
msgid "Another network capacity consideration for a multi-site deployment is the amount and performance of overlay networks available for tenant networks. If using shared tenant networks across zones, it is imperative that an external overlay manager or controller be used to map these overlays together. It is necessary to ensure the amount of possible IDs between the zones are identical."
msgstr ""

#: ./doc/arch-design/multi_site/section_tech_considerations_multi_site.xml:55(para)
msgid "As of the Kilo release, OpenStack Networking was not capable of managing tunnel IDs across installations. So if one site runs out of IDs, but another does not, that tenant's network is unable to reach the other site."
msgstr ""

#: ./doc/arch-design/multi_site/section_tech_considerations_multi_site.xml:60(para)
msgid "Capacity can take other forms as well. The ability for a region to grow depends on scaling out the number of available compute nodes. This topic is covered in greater detail in the section for compute-focused deployments. However, it may be necessary to grow cells in an individual region, depending on the size of your cluster and the ratio of virtual machines per hypervisor."
msgstr ""

#: ./doc/arch-design/multi_site/section_tech_considerations_multi_site.xml:67(para)
msgid "A third form of capacity comes in the multi-region-capable components of OpenStack. Centralized Object Storage is capable of serving objects through a single namespace across multiple regions. Since this works by accessing the object store through swift proxy, it is possible to overload the proxies. There are two options available to mitigate this issue:"
msgstr ""

#: ./doc/arch-design/multi_site/section_tech_considerations_multi_site.xml:75(para)
msgid "Deploy a large number of swift proxies. The drawback is that the proxies are not load-balanced and a large file request could continually hit the same proxy."
msgstr ""

#: ./doc/arch-design/multi_site/section_tech_considerations_multi_site.xml:80(para)
msgid "Add a caching HTTP proxy and load balancer in front of the swift proxies. Since swift objects are returned to the requester via HTTP, this load balancer would alleviate the load required on the swift proxies."
msgstr ""

#: ./doc/arch-design/multi_site/section_tech_considerations_multi_site.xml:87(para)
msgid "While constructing a multi-site OpenStack environment is the goal of this guide, the real test is whether an application can utilize it."
msgstr ""

#: ./doc/arch-design/multi_site/section_tech_considerations_multi_site.xml:90(para)
msgid "The Identity service is normally the first interface for OpenStack users and is required for almost all major operations within OpenStack. Therefore, it is important that you provide users with a single URL for Identity service authentication, and document the configuration of regions within the Identity service. Each of the sites defined in your installation is considered to be a region in Identity nomenclature. This is important for the users, as it is required to define the region name when providing actions to an API endpoint or in the dashboard."
msgstr ""

#: ./doc/arch-design/multi_site/section_tech_considerations_multi_site.xml:99(para)
msgid "Load balancing is another common issue with multi-site installations. While it is still possible to run HAproxy instances with Load-Balancer-as-a-Service, these are defined to a specific region. Some applications can manage this using internal mechanisms. Other applications may require the implementation of an external system, including global services load balancers or anycast-advertised DNS."
msgstr ""

#: ./doc/arch-design/multi_site/section_tech_considerations_multi_site.xml:106(para)
msgid "Depending on the storage model chosen during site design, storage replication and availability are also a concern for end-users. If an application can support regions, then it is possible to keep the object storage system separated by region. In this case, users who want to have an object available to more than one region need to perform cross-site replication. However, with a centralized swift proxy, the user may need to benchmark the replication timing of the Object Storage back end. Benchmarking allows the operational staff to provide users with an understanding of the amount of time required for a stored or modified object to become available to the entire environment."
msgstr ""

#: ./doc/arch-design/multi_site/section_tech_considerations_multi_site.xml:119(para)
msgid "Determining the performance of a multi-site installation involves considerations that do not come into play in a single-site deployment. Being a distributed deployment, performance in multi-site deployments may be affected in certain situations."
msgstr ""

#: ./doc/arch-design/multi_site/section_tech_considerations_multi_site.xml:124(para)
msgid "Since multi-site systems can be geographically separated, there may be greater latency or jitter when communicating across regions. This can especially impact systems like the OpenStack Identity service when making authentication attempts from regions that do not contain the centralized Identity implementation. It can also affect applications which rely on Remote Procedure Call (RPC) for normal operation. An example of this can be seen in high performance computing workloads."
msgstr ""

#: ./doc/arch-design/multi_site/section_tech_considerations_multi_site.xml:132(para)
msgid "Storage availability can also be impacted by the architecture of a multi-site deployment. A centralized Object Storage service requires more time for an object to be available to instances locally in regions where the object was not created. Some applications may need to be tuned to account for this effect. Block Storage does not currently have a method for replicating data across multiple regions, so applications that depend on available block storage need to manually cope with this limitation by creating duplicate block storage entries in each region."
msgstr ""

#: ./doc/arch-design/multi_site/section_tech_considerations_multi_site.xml:145(para)
msgid "Most OpenStack installations require a bare minimum set of pieces to function. These include the OpenStack Identity (keystone) for authentication, OpenStack Compute (nova) for compute, OpenStack Image service (glance) for image storage, OpenStack Networking (neutron) for networking, and potentially an object store in the form of OpenStack Object Storage (swift). Deploying a multi-site installation also demands extra components in order to coordinate between regions. A centralized Identity service is necessary to provide the single authentication point. A centralized dashboard is also recommended to provide a single login point and a mapping to the API and CLI options available. A centralized Object Storage service may also be used, but will require the installation of the swift proxy service."
msgstr ""

#: ./doc/arch-design/multi_site/section_tech_considerations_multi_site.xml:159(para)
msgid "It may also be helpful to install a few extra options in order to facilitate certain use cases. For example, installing Designate may assist in automatically generating DNS domains for each region with an automatically-populated zone full of resource records for each instance. This facilitates using DNS as a mechanism for determining which region will be selected for certain applications."
msgstr ""

#: ./doc/arch-design/multi_site/section_tech_considerations_multi_site.xml:166(para)
msgid "Another useful tool for managing a multi-site installation is Orchestration (heat). The Orchestration service allows the use of templates to define a set of instances to be launched together or for scaling existing sets. It can also be used to set up matching or differentiated groupings based on regions. For instance, if an application requires an equally balanced number of nodes across sites, the same heat template can be used to cover each site with small alterations to only the region name."
msgstr ""

#: ./doc/arch-design/multi_site/section_user_requirements_multi_site.xml:10(title)
msgid "Workload characteristics"
msgstr ""

#: ./doc/arch-design/multi_site/section_user_requirements_multi_site.xml:11(para)
msgid "An understanding of the expected workloads for a desired multi-site environment and use case is an important factor in the decision-making process. In this context, <literal>workload</literal> refers to the way the systems are used. A workload could be a single application or a suite of applications that work together. It could also be a duplicate set of applications that need to run in multiple cloud environments. Often in a multi-site deployment, the same workload will need to work identically in more than one physical location."
msgstr ""

#: ./doc/arch-design/multi_site/section_user_requirements_multi_site.xml:20(para)
msgid "This multi-site scenario likely includes one or more of the other scenarios in this book with the additional requirement of having the workloads in two or more locations. The following are some possible scenarios:"
msgstr ""

#: ./doc/arch-design/multi_site/section_user_requirements_multi_site.xml:24(para)
msgid "For many use cases the proximity of the user to their workloads has a direct influence on the performance of the application and therefore should be taken into consideration in the design. Certain applications require zero to minimal latency that can only be achieved by deploying the cloud in multiple locations. These locations could be in different data centers, cities, countries or geographical regions, depending on the user requirement and location of the users."
msgstr ""

#: ./doc/arch-design/multi_site/section_user_requirements_multi_site.xml:33(title)
msgid "Consistency of images and templates across different sites"
msgstr ""

#: ./doc/arch-design/multi_site/section_user_requirements_multi_site.xml:35(para)
msgid "It is essential that the deployment of instances is consistent across the different sites and built into the infrastructure. If the OpenStack Object Storage is used as a back end for the Image service, it is possible to create repositories of consistent images across multiple sites. Having central endpoints with multiple storage nodes allows consistent centralized storage for every site."
msgstr ""

#: ./doc/arch-design/multi_site/section_user_requirements_multi_site.xml:42(para)
msgid "Not using a centralized object store increases the operational overhead of maintaining a consistent image library. This could include development of a replication mechanism to handle the transport of images and the changes to the images across multiple sites."
msgstr ""

#: ./doc/arch-design/multi_site/section_user_requirements_multi_site.xml:49(para)
msgid "If high availability is a requirement to provide continuous infrastructure operations, a basic requirement of high availability should be defined."
msgstr ""

#: ./doc/arch-design/multi_site/section_user_requirements_multi_site.xml:52(para)
msgid "The OpenStack management components need to have a basic and minimal level of redundancy. The simplest example is the loss of any single site should have minimal impact on the availability of the OpenStack services."
msgstr ""

#: ./doc/arch-design/multi_site/section_user_requirements_multi_site.xml:56(para)
msgid "The <link xlink:href=\"http://docs.openstack.org/ha-guide/\"><citetitle>OpenStack High Availability Guide</citetitle></link> contains more information on how to provide redundancy for the OpenStack components."
msgstr ""

#: ./doc/arch-design/multi_site/section_user_requirements_multi_site.xml:61(para)
msgid "Multiple network links should be deployed between sites to provide redundancy for all components. This includes storage replication, which should be isolated to a dedicated network or VLAN with the ability to assign QoS to control the replication traffic or provide priority for this traffic. Note that if the data store is highly changeable, the network requirements could have a significant effect on the operational cost of maintaining the sites."
msgstr ""

#: ./doc/arch-design/multi_site/section_user_requirements_multi_site.xml:69(para)
msgid "The ability to maintain object availability in both sites has significant implications on the object storage design and implementation. It also has a significant impact on the WAN network design between the sites."
msgstr ""

#: ./doc/arch-design/multi_site/section_user_requirements_multi_site.xml:73(para)
msgid "Connecting more than two sites increases the challenges and adds more complexity to the design considerations. Multi-site implementations require planning to address the additional topology used for internal and external connectivity. Some options include full mesh topology, hub spoke, spine leaf, and 3D Torus."
msgstr ""

#: ./doc/arch-design/multi_site/section_user_requirements_multi_site.xml:78(para)
msgid "If applications running in a cloud are not cloud-aware, there should be clear measures and expectations to define what the infrastructure can and cannot support. An example would be shared storage between sites. It is possible, however such a solution is not native to OpenStack and requires a third-party hardware vendor to fulfill such a requirement. Another example can be seen in applications that are able to consume resources in object storage directly. These applications need to be cloud aware to make good use of an OpenStack Object Store."
msgstr ""

#: ./doc/arch-design/multi_site/section_user_requirements_multi_site.xml:89(title) ./doc/arch-design/hybrid/section_operational_considerations_hybrid.xml:31(title)
msgid "Application readiness"
msgstr ""

#: ./doc/arch-design/multi_site/section_user_requirements_multi_site.xml:90(para)
msgid "Some applications are tolerant of the lack of synchronized object storage, while others may need those objects to be replicated and available across regions. Understanding how the cloud implementation impacts new and existing applications is important for risk mitigation, and the overall success of a cloud project. Applications may have to be written or rewritten for an infrastructure with little to no redundancy, or with the cloud in mind."
msgstr ""

#: ./doc/arch-design/multi_site/section_user_requirements_multi_site.xml:100(para)
msgid "A greater number of sites increase cost and complexity for a multi-site deployment. Costs can be broken down into the following categories:"
msgstr ""

#: ./doc/arch-design/multi_site/section_user_requirements_multi_site.xml:105(para)
msgid "Compute resources"
msgstr ""

#: ./doc/arch-design/multi_site/section_user_requirements_multi_site.xml:108(para)
msgid "Networking resources"
msgstr ""

#: ./doc/arch-design/multi_site/section_user_requirements_multi_site.xml:111(para)
msgid "Replication"
msgstr ""

#: ./doc/arch-design/multi_site/section_user_requirements_multi_site.xml:117(para) ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:663(para)
msgid "Management"
msgstr ""

#: ./doc/arch-design/multi_site/section_user_requirements_multi_site.xml:120(para)
msgid "Operational costs"
msgstr ""

#: ./doc/arch-design/multi_site/section_user_requirements_multi_site.xml:124(title)
msgid "Site loss and recovery"
msgstr ""

#: ./doc/arch-design/multi_site/section_user_requirements_multi_site.xml:125(para)
msgid "Outages can cause partial or full loss of site functionality. Strategies should be implemented to understand and plan for recovery scenarios."
msgstr ""

#: ./doc/arch-design/multi_site/section_user_requirements_multi_site.xml:130(para)
msgid "The deployed applications need to continue to function and, more importantly, you must consider the impact on the performance and reliability of the application when a site is unavailable."
msgstr ""

#: ./doc/arch-design/multi_site/section_user_requirements_multi_site.xml:136(para)
msgid "It is important to understand what happens to the replication of objects and data between the sites when a site goes down. If this causes queues to start building up, consider how long these queues can safely exist until an error occurs."
msgstr ""

#: ./doc/arch-design/multi_site/section_user_requirements_multi_site.xml:143(para)
msgid "After an outage, ensure the method for resuming proper operations of a site is implemented when it comes back online. We recommend you architect the recovery to avoid race conditions."
msgstr ""

#: ./doc/arch-design/multi_site/section_user_requirements_multi_site.xml:149(title)
msgid "Compliance and geo-location"
msgstr ""

#: ./doc/arch-design/multi_site/section_user_requirements_multi_site.xml:150(para)
msgid "An organization may have certain legal obligations and regulatory compliance measures which could require certain workloads or data to not be located in certain regions."
msgstr ""

#: ./doc/arch-design/multi_site/section_user_requirements_multi_site.xml:154(title)
msgid "Auditing"
msgstr ""

#: ./doc/arch-design/multi_site/section_user_requirements_multi_site.xml:155(para)
msgid "A well thought-out auditing strategy is important in order to be able to quickly track down issues. Keeping track of changes made to security groups and tenant changes can be useful in rolling back the changes if they affect production. For example, if all security group rules for a tenant disappeared, the ability to quickly track down the issue would be important for operational and legal reasons."
msgstr ""

#: ./doc/arch-design/multi_site/section_user_requirements_multi_site.xml:163(title)
msgid "Separation of duties"
msgstr ""

#: ./doc/arch-design/multi_site/section_user_requirements_multi_site.xml:164(para)
msgid "A common requirement is to define different roles for the different cloud administration functions. An example would be a requirement to segregate the duties and permissions by site."
msgstr ""

#: ./doc/arch-design/multi_site/section_user_requirements_multi_site.xml:169(title)
msgid "Authentication between sites"
msgstr ""

#: ./doc/arch-design/multi_site/section_user_requirements_multi_site.xml:170(para)
msgid "It is recommended to have a single authentication domain rather than a separate implementation for each and every site. This requires an authentication mechanism that is highly available and distributed to ensure continuous operation. Authentication server locality might be required and should be planned for."
msgstr ""

#. When image changes, this message will be marked fuzzy or untranslated for you.
#. It doesn't matter what you translate it to: it's not used at all.
#: ./doc/arch-design/multi_site/section_prescriptive_examples_multi_site.xml:87(None)
msgid "@@image: '../figures/Multi-Site_Customer_Edge.png'; md5=01850cf774e7075bd7202c6e7f087f36"
msgstr ""

#. When image changes, this message will be marked fuzzy or untranslated for you.
#. It doesn't matter what you translate it to: it's not used at all.
#: ./doc/arch-design/multi_site/section_prescriptive_examples_multi_site.xml:194(None)
msgid "@@image: '../figures/Multi-site_Geo_Redundant_LB.png'; md5=c94a96f6084c2e50a0eb6846f6fde479"
msgstr ""

#. When image changes, this message will be marked fuzzy or untranslated for you.
#. It doesn't matter what you translate it to: it's not used at all.
#: ./doc/arch-design/multi_site/section_prescriptive_examples_multi_site.xml:231(None)
msgid "@@image: '../figures/Multi-Site_shared_keystone1.png'; md5=eaef18e7f04eec7e3f8968ad69aed7d3"
msgstr ""

#: ./doc/arch-design/multi_site/section_prescriptive_examples_multi_site.xml:13(para)
msgid "There are multiple ways to build a multi-site OpenStack installation, based on the needs of the intended workloads. Below are example architectures based on different requirements. These examples are meant as a reference, and not a hard and fast rule for deployments. Use the previous sections of this chapter to assist in selecting specific components and implementations based on specific needs."
msgstr ""

#: ./doc/arch-design/multi_site/section_prescriptive_examples_multi_site.xml:20(para)
msgid "A large content provider needs to deliver content to customers that are geographically dispersed. The workload is very sensitive to latency and needs a rapid response to end-users. After reviewing the user, technical and operational considerations, it is determined beneficial to build a number of regions local to the customer's edge. Rather than build a few large, centralized data centers, the intent of the architecture is to provide a pair of small data centers in locations that are closer to the customer. In this use case, spreading applications out allows for different horizontal scaling than a traditional compute workload scale. The intent is to scale by creating more copies of the application in closer proximity to the users that need it most, in order to ensure faster response time to user requests. This provider deploys two datacenters at each of the four chosen regions. The implications of this design are based around the method of placing copies of resources in each of the remote regions. Swift objects, Glance images, and block storage need to be manually replicated into each region. This may be beneficial for some systems, such as the case of content service, where only some of the content needs to exist in some but not all regions. A centralized Keystone is recommended to ensure authentication and that access to the API endpoints is easily manageable."
msgstr ""

#: ./doc/arch-design/multi_site/section_prescriptive_examples_multi_site.xml:44(para)
msgid "It is recommended that you install an automated DNS system such as Designate. Application administrators need a way to manage the mapping of which application copy exists in each region and how to reach it, unless an external Dynamic DNS system is available. Designate assists by making the process automatic and by populating the records in the each region's zone."
msgstr ""

#: ./doc/arch-design/multi_site/section_prescriptive_examples_multi_site.xml:50(para)
msgid "Telemetry for each region is also deployed, as each region may grow differently or be used at a different rate. Ceilometer collects each region's meters from each of the controllers and report them back to a central location. This is useful both to the end user and the administrator of the OpenStack environment. The end user will find this method useful, as it makes possible to determine if certain locations are experiencing higher load than others, and take appropriate action. Administrators also benefit by possibly being able to forecast growth per region, rather than expanding the capacity of all regions simultaneously, therefore maximizing the cost-effectiveness of the multi-site design."
msgstr ""

#: ./doc/arch-design/multi_site/section_prescriptive_examples_multi_site.xml:63(para)
msgid "One of the key decisions of running this infrastructure is whether or not to provide a redundancy model. Two types of redundancy and high availability models in this configuration can be implemented. The first type is the availability of central OpenStack components. Keystone can be made highly available in three central data centers that host the centralized OpenStack components. This prevents a loss of any one of the regions causing an outage in service. It also has the added benefit of being able to run a central storage repository as a primary cache for distributing content to each of the regions."
msgstr ""

#: ./doc/arch-design/multi_site/section_prescriptive_examples_multi_site.xml:74(para)
msgid "The second redundancy type is the edge data center itself. A second data center in each of the edge regional locations house a second region near the first region. This ensures that the application does not suffer degraded performance in terms of latency and availability."
msgstr ""

#: ./doc/arch-design/multi_site/section_prescriptive_examples_multi_site.xml:79(para)
msgid "<xref linkend=\"multi-site_customer_edge\"/> depicts the solution designed to have both a centralized set of core data centers for OpenStack services and paired edge data centers:"
msgstr ""

#: ./doc/arch-design/multi_site/section_prescriptive_examples_multi_site.xml:83(title)
msgid "Multi-site architecture example"
msgstr ""

#: ./doc/arch-design/multi_site/section_prescriptive_examples_multi_site.xml:92(title)
msgid "Geo-redundant load balancing"
msgstr ""

#: ./doc/arch-design/multi_site/section_prescriptive_examples_multi_site.xml:93(para)
msgid "A large-scale web application has been designed with cloud principles in mind. The application is designed provide service to application store, on a 24/7 basis. The company has typical two tier architecture with a web front-end servicing the customer requests, and a NoSQL database back end storing the information."
msgstr ""

#: ./doc/arch-design/multi_site/section_prescriptive_examples_multi_site.xml:99(para)
msgid "As of late there has been several outages in number of major public cloud providers due to applications running out of a single geographical location. The design therefore should mitigate the chance of a single site causing an outage for their business."
msgstr ""

#: ./doc/arch-design/multi_site/section_prescriptive_examples_multi_site.xml:104(para) ./doc/arch-design/generalpurpose/section_prescriptive_example_general_purpose.xml:30(para)
msgid "The solution would consist of the following OpenStack components:"
msgstr ""

#: ./doc/arch-design/multi_site/section_prescriptive_examples_multi_site.xml:108(para) ./doc/arch-design/generalpurpose/section_prescriptive_example_general_purpose.xml:34(para)
msgid "A firewall, switches and load balancers on the public facing network connections."
msgstr ""

#: ./doc/arch-design/multi_site/section_prescriptive_examples_multi_site.xml:112(para)
msgid "OpenStack Controller services running, Networking, dashboard, Block Storage and Compute running locally in each of the three regions. Identity service, Orchestration service, Telemetry service, Image service and Object Storage service can be installed centrally, with nodes in each of the region providing a redundant OpenStack Controller plane throughout the globe."
msgstr ""

#: ./doc/arch-design/multi_site/section_prescriptive_examples_multi_site.xml:121(para) ./doc/arch-design/generalpurpose/section_prescriptive_example_general_purpose.xml:44(para)
msgid "OpenStack Compute nodes running the KVM hypervisor."
msgstr ""

#: ./doc/arch-design/multi_site/section_prescriptive_examples_multi_site.xml:125(para)
msgid "OpenStack Object Storage for serving static objects such as images can be used to ensure that all images are standardized across all the regions, and replicated on a regular basis."
msgstr ""

#: ./doc/arch-design/multi_site/section_prescriptive_examples_multi_site.xml:131(para)
msgid "A distributed DNS service available to all regions that allows for dynamic update of DNS records of deployed instances."
msgstr ""

#: ./doc/arch-design/multi_site/section_prescriptive_examples_multi_site.xml:136(para)
msgid "A geo-redundant load balancing service can be used to service the requests from the customers based on their origin."
msgstr ""

#: ./doc/arch-design/multi_site/section_prescriptive_examples_multi_site.xml:141(para)
msgid "An autoscaling heat template can be used to deploy the application in the three regions. This template includes:"
msgstr ""

#: ./doc/arch-design/multi_site/section_prescriptive_examples_multi_site.xml:145(para)
msgid "Web Servers, running Apache."
msgstr ""

#: ./doc/arch-design/multi_site/section_prescriptive_examples_multi_site.xml:148(para)
msgid "Appropriate <literal>user_data</literal> to populate the central DNS servers upon instance launch."
msgstr ""

#: ./doc/arch-design/multi_site/section_prescriptive_examples_multi_site.xml:152(para)
msgid "Appropriate Telemetry alarms that maintain state of the application and allow for handling of region or instance failure."
msgstr ""

#: ./doc/arch-design/multi_site/section_prescriptive_examples_multi_site.xml:157(para)
msgid "Another autoscaling Heat template can be used to deploy a distributed MongoDB shard over the three locations, with the option of storing required data on a globally available swift container. According to the usage and load on the database server, additional shards can be provisioned according to the thresholds defined in Telemetry."
msgstr ""

#. <para>The reason that three regions were selected here was because of
#.         the fear of having abnormal load on a single region in the
#.         event of a failure. Two data center would have been sufficient
#.       had the requirements been met.</para>
#: ./doc/arch-design/multi_site/section_prescriptive_examples_multi_site.xml:167(para)
msgid "Two data centers would have been sufficient had the requirements been met. But three regions are selected here to avoid abnormal load on a single region in the event of a failure."
msgstr ""

#: ./doc/arch-design/multi_site/section_prescriptive_examples_multi_site.xml:170(para)
msgid "Orchestration is used because of the built-in functionality of autoscaling and auto healing in the event of increased load. Additional configuration management tools, such as Puppet or Chef could also have been used in this scenario, but were not chosen since Orchestration had the appropriate built-in hooks into the OpenStack cloud, whereas the other tools were external and not native to OpenStack. In addition, external tools were not needed since this deployment scenario was straight forward."
msgstr ""

#: ./doc/arch-design/multi_site/section_prescriptive_examples_multi_site.xml:179(para)
msgid "OpenStack Object Storage is used here to serve as a back end for the Image service since it is the most suitable solution for a globally distributed storage solution with its own replication mechanism. Home grown solutions could also have been used including the handling of replication, but were not chosen, because Object Storage is already an intricate part of the infrastructure and a proven solution."
msgstr ""

#: ./doc/arch-design/multi_site/section_prescriptive_examples_multi_site.xml:186(para)
msgid "An external load balancing service was used and not the LBaaS in OpenStack because the solution in OpenStack is not redundant and does not have any awareness of geo location."
msgstr ""

#: ./doc/arch-design/multi_site/section_prescriptive_examples_multi_site.xml:190(title)
msgid "Multi-site geo-redundant architecture"
msgstr ""

#: ./doc/arch-design/multi_site/section_prescriptive_examples_multi_site.xml:200(title)
msgid "Location-local service"
msgstr ""

#: ./doc/arch-design/multi_site/section_prescriptive_examples_multi_site.xml:201(para)
msgid "A common use for multi-site OpenStack deployment is creating a Content Delivery Network. An application that uses a location-local architecture requires low network latency and proximity to the user to provide an optimal user experience and reduce the cost of bandwidth and transit. The content resides on sites closer to the customer, instead of a centralized content store that requires utilizing higher cost cross-country links."
msgstr ""

#: ./doc/arch-design/multi_site/section_prescriptive_examples_multi_site.xml:209(para)
msgid "This architecture includes a geo-location component that places user requests to the closest possible node. In this scenario, 100% redundancy of content across every site is a goal rather than a requirement, with the intent to maximize the amount of content available within a minimum number of network hops for end users. Despite these differences, the storage replication configuration has significant overlap with that of a geo-redundant load balancing use case."
msgstr ""

#: ./doc/arch-design/multi_site/section_prescriptive_examples_multi_site.xml:218(para)
msgid "In <xref linkend=\"multi-site_shared_shared_keystone\"/>, the application utilizing this multi-site OpenStack install that is location-aware would launch web server or content serving instances on the compute cluster in each site. Requests from clients are first sent to a global services load balancer that determines the location of the client, then routes the request to the closest OpenStack site where the application completes the request."
msgstr ""

#: ./doc/arch-design/multi_site/section_prescriptive_examples_multi_site.xml:227(title)
msgid "Multi-site shared keystone architecture"
msgstr ""

#: ./doc/arch-design/hybrid/section_operational_considerations_hybrid.xml:9(para)
msgid "Hybrid cloud deployments present complex operational challenges. Differences between provider clouds can cause incompatibilities with workloads or Cloud Management Platforms (CMP). Cloud providers may also offer different levels of integration with competing cloud offerings."
msgstr ""

#: ./doc/arch-design/hybrid/section_operational_considerations_hybrid.xml:14(para)
msgid "Monitoring is critical to maintaining a hybrid cloud, and it is important to determine if a CMP supports monitoring of all the clouds involved, or if compatible APIs are available to be queried for necessary information."
msgstr ""

#: ./doc/arch-design/hybrid/section_operational_considerations_hybrid.xml:20(title)
msgid "Agility"
msgstr ""

#: ./doc/arch-design/hybrid/section_operational_considerations_hybrid.xml:21(para)
msgid "Hybrid clouds provide application availability across different cloud environments and technologies. This availability enables the deployment to survive disaster in any single cloud environment. Each cloud should provide the means to create instances quickly in response to capacity issues or failure elsewhere in the hybrid cloud."
msgstr ""

#: ./doc/arch-design/hybrid/section_operational_considerations_hybrid.xml:32(para)
msgid "Enterprise workloads that depend on the underlying infrastructure for availability are not designed to run on OpenStack. If the application cannot tolerate infrastructure failures, it is likely to require significant operator intervention to recover. Applications for hybrid clouds must be fault tolerant, with an SLA that is not tied to the underlying infrastructure. Ideally, cloud applications should be able to recover when entire racks and data centers experience an outage."
msgstr ""

#: ./doc/arch-design/hybrid/section_operational_considerations_hybrid.xml:45(para)
msgid "If a deployment includes a public cloud, predicting upgrades may not be possible. Carefully examine provider SLAs."
msgstr ""

#: ./doc/arch-design/hybrid/section_operational_considerations_hybrid.xml:48(para)
msgid "At massive scale, even when dealing with a cloud that offers an SLA with a high percentage of uptime, workloads must be able to recover quickly."
msgstr ""

#: ./doc/arch-design/hybrid/section_operational_considerations_hybrid.xml:52(para)
msgid "When upgrading private cloud deployments, minimize disruption by making incremental changes and providing a facility to either rollback or continue to roll forward when using a continuous delivery model."
msgstr ""

#: ./doc/arch-design/hybrid/section_operational_considerations_hybrid.xml:56(para)
msgid "You may need to coordinate CMP upgrades with hybrid cloud upgrades if there are API changes."
msgstr ""

#: ./doc/arch-design/hybrid/section_operational_considerations_hybrid.xml:61(title)
msgid "Network Operation Center"
msgstr ""

#: ./doc/arch-design/hybrid/section_operational_considerations_hybrid.xml:62(para)
msgid "Consider infrastructure control when planning the Network Operation Center (NOC) for a hybrid cloud environment. If a significant portion of the cloud is on externally managed systems, prepare for situations where it may not be possible to make changes. Additionally, providers may differ on how infrastructure must be managed and exposed. This can lead to delays in root cause analysis where each insists the blame lies with the other provider."
msgstr ""

#: ./doc/arch-design/hybrid/section_operational_considerations_hybrid.xml:72(para)
msgid "Ensure that the network structure connects all clouds to form integrated system, keeping in mind the state of handoffs. These handoffs must both be as reliable as possible and include as little latency as possible to ensure the best performance of the overall system."
msgstr ""

#: ./doc/arch-design/hybrid/section_operational_considerations_hybrid.xml:80(title)
msgid "Maintainability"
msgstr ""

#: ./doc/arch-design/hybrid/section_operational_considerations_hybrid.xml:81(para)
msgid "Hybrid clouds rely on third party systems and processes. As a result, it is not possible to guarantee proper maintenance of the overall system. Instead, be prepared to abandon workloads and recreate them in an improved state."
msgstr ""

#: ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:13(para)
msgid "A hybrid cloud environment requires inspection and understanding of technical issues in external data centers that may not be in your control. Ideally, select an architecture and CMP that are adaptable to changing environments."
msgstr ""

#: ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:17(para)
msgid "Using diverse cloud platforms increases the risk of compatibility issues, but clouds using the same version and distribution of OpenStack are less likely to experience problems."
msgstr ""

#: ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:20(para)
msgid "Clouds that exclusively use the same versions of OpenStack should have no issues, regardless of distribution. More recent distributions are less likely to encounter incompatibility between versions. An OpenStack community initiative defines core functions that need to remain backward compatible between supported versions. For example, the DefCore initiative defines basic functions that every distribution must support in order to use the name <productname>OpenStack</productname>."
msgstr ""

#: ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:28(para)
msgid "Vendors can add proprietary customization to their distributions. If an application or architecture makes use of these features, it can be difficult to migrate to or use other types of environments."
msgstr ""

#: ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:31(para)
msgid "If an environment includes non-OpenStack clouds, it may experience compatibility problems. CMP tools must account for the differences in the handling of operations and the implementation of services."
msgstr ""

#: ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:35(title)
msgid "Possible cloud incompatibilities"
msgstr ""

#: ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:37(para)
msgid "Instance deployment"
msgstr ""

#: ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:40(para)
msgid "Network management"
msgstr ""

#: ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:43(para)
msgid "Application management"
msgstr ""

#: ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:46(para)
msgid "Services implementation"
msgstr ""

#: ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:52(para)
msgid "One of the primary reasons many organizations use a hybrid cloud is to increase capacity without making large capital investments."
msgstr ""

#: ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:55(para)
msgid "Capacity and the placement of workloads are key design considerations for hybrid clouds. The long-term capacity plan for these designs must incorporate growth over time to prevent permanent consumption of more expensive external clouds. To avoid this scenario, account for future applications' capacity requirements and plan growth appropriately."
msgstr ""

#: ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:61(para)
msgid "It is difficult to predict the amount of load a particular application might incur if the number of users fluctuates, or the application experiences an unexpected increase in use. It is possible to define application requirements in terms of vCPU, RAM, bandwidth, or other resources and plan appropriately. However, other clouds might not use the same meter or even the same oversubscription rates."
msgstr ""

#: ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:68(para)
msgid "Oversubscription is a method to emulate more capacity than may physically be present. For example, a physical hypervisor node with 32GB RAM may host 24 instances, each provisioned with 2GB RAM. As long as all 24 instances do not concurrently use 2 full gigabytes, this arrangement works well. However, some hosts take oversubscription to extremes and, as a result, performance can be inconsistent. If at all possible, determine what the oversubscription rates of each host are and plan capacity accordingly."
msgstr ""

#: ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:81(para)
msgid "A CMP must be aware of what workloads are running, where they are running, and their preferred utilizations. For example, in most cases it is desirable to run as many workloads internally as possible, utilizing other resources only when necessary. On the other hand, situations exist in which the opposite is true, such as when an internal cloud is only for development and stressing it is undesirable. A cost model of various scenarios and consideration of internal priorities helps with this decision. To improve efficiency, automate these decisions when possible."
msgstr ""

#: ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:90(para)
msgid "The Telemetry service (ceilometer) provides information on the usage of various OpenStack components. Note the following:"
msgstr ""

#: ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:94(para)
msgid "If Telemetry must retain a large amount of data, for example when monitoring a large or active cloud, we recommend using a NoSQL back end such as MongoDB."
msgstr ""

#: ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:100(para)
msgid "You must monitor connections to non-OpenStack clouds and report this information to the CMP."
msgstr ""

#: ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:109(para)
msgid "Performance is critical to hybrid cloud deployments, and they are affected by many of the same issues as multi-site deployments, such as network latency between sites. Also consider the time required to run a workload in different clouds and methods for reducing this time. This may require moving data closer to applications or applications closer to the data they process, and grouping functionality so that connections that require low latency take place over a single cloud rather than spanning clouds. This may also require a CMP that can determine which cloud can most efficiently run which types of workloads."
msgstr ""

#: ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:119(para)
msgid "As with utilization, native OpenStack tools help improve performance. For example, you can use Telemetry to measure performance and the Orchestration service (heat) to react to changes in demand."
msgstr ""

#: ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:123(para)
msgid "Orchestration requires special client configurations to integrate with Amazon Web Services. For other types of clouds, use CMP features."
msgstr ""

#: ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:131(title)
msgid "Components"
msgstr ""

#: ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:132(para)
msgid "Using more than one cloud in any design requires consideration of four OpenStack tools:"
msgstr ""

#: ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:138(para)
msgid "Regardless of deployment location, hypervisor choice has a direct effect on how difficult it is to integrate with additional clouds."
msgstr ""

#: ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:146(para)
msgid "Whether using OpenStack Networking (neutron) or legacy networking (nova-network), it is necessary to understand network integration capabilities in order to connect between clouds."
msgstr ""

#: ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:155(para)
msgid "Use of Telemetry depends, in large part, on what the other parts of the cloud you are using."
msgstr ""

#: ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:162(para)
msgid "Orchestration can be a valuable tool in orchestrating tasks a CMP decides are necessary in an OpenStack-based cloud."
msgstr ""

#: ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:170(title)
msgid "Special considerations"
msgstr ""

#: ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:171(para)
msgid "Hybrid cloud deployments require consideration of two issues that are not common in other situations:"
msgstr ""

#: ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:175(term) ./doc/arch-design/hybrid/section_architecture_hybrid.xml:24(title)
msgid "Image portability"
msgstr ""

#: ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:177(para)
msgid "As of the Kilo release, there is no common image format that is usable by all clouds. Conversion or recreation of images is necessary if migrating between clouds. To simplify deployment, use the smallest and simplest images feasible, install only what is necessary, and use a deployment manager such as Chef or Puppet. Do not use golden images to speed up the process unless you repeatedly deploy the same images on the same cloud."
msgstr ""

#: ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:187(term)
msgid "API differences"
msgstr ""

#: ./doc/arch-design/hybrid/section_tech_considerations_hybrid.xml:189(para)
msgid "Avoid using a hybrid cloud deployment with more than just OpenStack (or with different versions of OpenStack) as API changes can cause compatibility issues."
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:9(para)
msgid "Hybrid cloud architectures are complex, especially those that use heterogeneous cloud platforms. Ensure that design choices match requirements so that the benefits outweigh the inherent additional complexity and risks."
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:14(title)
msgid "Business considerations when designing a hybrid cloud deployment"
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:19(para)
msgid "A hybrid cloud architecture involves multiple vendors and technical architectures. These architectures may be more expensive to deploy and maintain. Operational costs can be higher because of the need for more sophisticated orchestration and brokerage tools than in other architectures. In contrast, overall operational costs might be lower by virtue of using a cloud brokerage tool to deploy the workloads to the most cost effective platform."
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:31(term) ./doc/arch-design/generalpurpose/section_user_requirements_general_purpose.xml:53(term)
msgid "Revenue opportunity"
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:33(para)
msgid "Revenue opportunities vary based on the intent and use case of the cloud. As a commercial, customer-facing product, you must consider whether building over multiple platforms makes the design more attractive to customers."
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:40(term)
msgid "Time-to-market"
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:42(para)
msgid "One common reason to use cloud platforms is to improve the time-to-market of a new product or application. For example, using multiple cloud platforms is viable because there is an existing investment in several applications. It is faster to tie the investments together rather than migrate the components and refactoring them to a single platform."
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:51(term)
msgid "Business or technical diversity"
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:53(para)
msgid "Organizations leveraging cloud-based services can embrace business diversity and utilize a hybrid cloud design to spread their workloads across multiple cloud providers. This ensures that no single cloud provider is the sole host for an application."
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:61(term)
msgid "Application momentum"
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:63(para)
msgid "Businesses with existing applications may find that it is more cost effective to integrate applications on multiple cloud platforms than migrating them to a single platform."
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:71(title)
msgid "Workload considerations"
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:72(para)
msgid "A workload can be a single application or a suite of applications that work together. It can also be a duplicate set of applications that need to run on multiple cloud environments. In a hybrid cloud deployment, the same workload often needs to function equally well on radically different public and private cloud environments. The architecture needs to address these potential conflicts, complexity, and platform incompatibilities."
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:81(title)
msgid "Use cases for a hybrid cloud architecture"
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:83(term)
msgid "Dynamic resource expansion or bursting"
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:85(para)
msgid "An application that requires additional resources may suit a multiple cloud architecture. For example, a retailer needs additional resources during the holiday season, but does not want to add private cloud resources to meet the peak demand. The user can accommodate the increased load by bursting to a public cloud for these peak load periods. These bursts could be for long or short cycles ranging from hourly to yearly."
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:97(term)
msgid "Disaster recovery and business continuity"
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:99(para)
msgid "Cheaper storage makes the public cloud suitable for maintaining backup applications."
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:104(term)
msgid "Federated hypervisor and instance management"
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:106(para)
msgid "Adding self-service, charge back, and transparent delivery of the resources from a federated pool can be cost effective. In a hybrid cloud environment, this is a particularly important consideration. Look for a cloud that provides cross-platform hypervisor support and robust instance management tools."
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:115(term)
msgid "Application portfolio integration"
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:117(para)
msgid "An enterprise cloud delivers efficient application portfolio management and deployments by leveraging self-service features and rules according to use. Integrating existing cloud environments is a common driver when building hybrid cloud architectures."
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:125(term)
msgid "Migration scenarios"
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:127(para)
msgid "Hybrid cloud architecture enables the migration of applications between different clouds."
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:134(para)
msgid "A combination of locations and platforms enables a level of availability that is not possible with a single platform. This approach increases design complexity."
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:141(para)
msgid "As running a workload on multiple cloud platforms increases design complexity, we recommend first exploring options such as transferring workloads across clouds at the application, instance, cloud platform, hypervisor, and network levels."
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:148(title)
msgid "Tools considerations"
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:149(para)
msgid "Hybrid cloud designs must incorporate tools to facilitate working across multiple clouds."
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:152(title)
msgid "Tool functions"
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:154(term)
msgid "Broker between clouds"
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:156(para)
msgid "Brokering software evaluates relative costs between different cloud platforms. Cloud Management Platforms (CMP) allow the designer to determine the right location for the workload based on predetermined criteria."
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:163(term)
msgid "Facilitate orchestration across the clouds"
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:165(para)
msgid "CMPs simplify the migration of application workloads between public, private, and hybrid cloud platforms. We recommend using cloud orchestration tools for managing a diverse portfolio of systems and applications across multiple cloud platforms."
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:176(title)
msgid "Network considerations"
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:177(para)
msgid "It is important to consider the functionality, security, scalability, availability, and testability of network when choosing a CMP and cloud provider."
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:182(para)
msgid "Decide on a network framework and design minimum functionality tests. This ensures testing and functionality persists during and after upgrades."
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:188(para)
msgid "Scalability across multiple cloud providers may dictate which underlying network framework you choose in different cloud providers. It is important to present the network API functions and to verify that functionality persists across all cloud endpoints chosen."
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:196(para)
msgid "High availability implementations vary in functionality and design. Examples of some common methods are active-hot-standby, active-passive, and active-active. Development of high availability and test frameworks is necessary to insure understanding of functionality and limitations."
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:204(para)
msgid "Consider the security of data between the client and the endpoint, and of traffic that traverses the multiple clouds."
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:212(title)
msgid "Risk mitigation and management considerations"
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:213(para)
msgid "Hybrid cloud architectures introduce additional risk because they are more complex than a single cloud design and may involve incompatible components or tools. However, they also reduce risk by spreading workloads over multiple providers."
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:218(title)
msgid "Hybrid cloud risks"
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:220(term)
msgid "Provider availability or implementation details"
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:222(para)
msgid "Business changes can affect provider availability. Likewise, changes in a provider's service can disrupt a hybrid cloud environment or increase costs."
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:229(term)
msgid "Differing SLAs"
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:231(para)
msgid "Hybrid cloud designs must accommodate differences in SLAs between providers, and consider their enforceability."
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:236(term)
msgid "Security levels"
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:238(para)
msgid "Securing multiple cloud environments is more complex than securing single cloud environments. We recommend addressing concerns at the application, network, and cloud platform levels. Be aware that each cloud platform approaches security differently, and a hybrid cloud design must address and compensate for these differences."
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:248(term)
msgid "Provider API changes"
msgstr ""

#: ./doc/arch-design/hybrid/section_user_requirements_hybrid.xml:250(para)
msgid "Consumers of external clouds rarely have control over provider changes to APIs, and changes can break compatibility. Using only the most common and basic APIs can minimize potential conflicts."
msgstr ""

#. When image changes, this message will be marked fuzzy or untranslated for you.
#. It doesn't matter what you translate it to: it's not used at all.
#: ./doc/arch-design/hybrid/section_prescriptive_examples_hybrid.xml:47(None)
msgid "@@image: '../figures/Multi-Cloud_Priv-Pub3.png'; md5=8fdb44f876665e2aa1bd793607c4537e"
msgstr ""

#. When image changes, this message will be marked fuzzy or untranslated for you.
#. It doesn't matter what you translate it to: it's not used at all.
#: ./doc/arch-design/hybrid/section_prescriptive_examples_hybrid.xml:82(None) ./doc/arch-design/hybrid/section_architecture_hybrid.xml:19(None)
msgid "@@image: '../figures/Multi-Cloud_Priv-AWS4.png'; md5=3bba96b0b6ac0341a05581b00160ff17"
msgstr ""

#. When image changes, this message will be marked fuzzy or untranslated for you.
#. It doesn't matter what you translate it to: it's not used at all.
#: ./doc/arch-design/hybrid/section_prescriptive_examples_hybrid.xml:121(None)
msgid "@@image: '../figures/Multi-Cloud_failover2.png'; md5=5a7be4a15d381288659c7268dff6724b"
msgstr ""

#: ./doc/arch-design/hybrid/section_prescriptive_examples_hybrid.xml:9(para)
msgid "Hybrid cloud environments are designed for these use cases:"
msgstr ""

#: ./doc/arch-design/hybrid/section_prescriptive_examples_hybrid.xml:13(para)
msgid "Bursting workloads from private to public OpenStack clouds"
msgstr ""

#: ./doc/arch-design/hybrid/section_prescriptive_examples_hybrid.xml:17(para)
msgid "Bursting workloads from private to public non-OpenStack clouds"
msgstr ""

#: ./doc/arch-design/hybrid/section_prescriptive_examples_hybrid.xml:21(para)
msgid "High availability across clouds (for technical diversity)"
msgstr ""

#: ./doc/arch-design/hybrid/section_prescriptive_examples_hybrid.xml:25(para)
msgid "This chapter provides examples of environments that address each of these use cases."
msgstr ""

#: ./doc/arch-design/hybrid/section_prescriptive_examples_hybrid.xml:28(title)
msgid "Bursting to a public OpenStack cloud"
msgstr ""

#: ./doc/arch-design/hybrid/section_prescriptive_examples_hybrid.xml:29(para)
msgid "Company A's data center is running low on capacity. It is not possible to expand the data center in the foreseeable future. In order to accommodate the continuously growing need for development resources in the organization, Company A decides to use resources in the public cloud."
msgstr ""

#: ./doc/arch-design/hybrid/section_prescriptive_examples_hybrid.xml:35(para)
msgid "Company A has an established data center with a substantial amount of hardware. Migrating the workloads to a public cloud is not feasible."
msgstr ""

#: ./doc/arch-design/hybrid/section_prescriptive_examples_hybrid.xml:38(para)
msgid "The company has an internal cloud management platform that directs requests to the appropriate cloud, depending on the local capacity. This is a custom in-house application written for this specific purpose."
msgstr ""

#: ./doc/arch-design/hybrid/section_prescriptive_examples_hybrid.xml:42(para)
msgid "This solution is depicted in the figure below:"
msgstr ""

#: ./doc/arch-design/hybrid/section_prescriptive_examples_hybrid.xml:50(para)
msgid "This example shows two clouds with a Cloud Management Platform (CMP) connecting them. This guide does not discuss a specific CMP, but describes how the Orchestration and Telemetry services handle, manage, and control workloads."
msgstr ""

#: ./doc/arch-design/hybrid/section_prescriptive_examples_hybrid.xml:54(para)
msgid "The private OpenStack cloud has at least one controller and at least one compute node. It includes metering using the Telemetry service. The Telemetry service captures the load increase and the CMP processes the information. If there is available capacity, the CMP uses the OpenStack API to call the Orchestration service. This creates instances on the private cloud in response to user requests. When capacity is not available on the private cloud, the CMP issues a request to the Orchestration service API of the public cloud. This creates the instance on the public cloud."
msgstr ""

#: ./doc/arch-design/hybrid/section_prescriptive_examples_hybrid.xml:65(para)
msgid "In this example, Company A does not direct the deployments to an external public cloud due to concerns regarding resource control, security, and increased operational expense"
msgstr ""

#: ./doc/arch-design/hybrid/section_prescriptive_examples_hybrid.xml:71(title)
msgid "Bursting to a public non-OpenStack cloud"
msgstr ""

#: ./doc/arch-design/hybrid/section_prescriptive_examples_hybrid.xml:72(para)
msgid "The second example examines bursting workloads from the private cloud into a non-OpenStack public cloud using Amazon Web Services (AWS) to take advantage of additional capacity and to scale applications."
msgstr ""

#: ./doc/arch-design/hybrid/section_prescriptive_examples_hybrid.xml:76(para)
msgid "The following diagram demonstrates an OpenStack-to-AWS hybrid cloud:"
msgstr ""

#: ./doc/arch-design/hybrid/section_prescriptive_examples_hybrid.xml:85(para)
msgid "Company B states that its developers are already using AWS and do not want to change to a different provider."
msgstr ""

#: ./doc/arch-design/hybrid/section_prescriptive_examples_hybrid.xml:87(para)
msgid "If the CMP is capable of connecting to an external cloud provider with an appropriate API, the workflow process remains the same as the previous scenario. The actions the CMP takes, such as monitoring loads and creating new instances, stay the same. However, the CMP performs actions in the public cloud using applicable API calls."
msgstr ""

#: ./doc/arch-design/hybrid/section_prescriptive_examples_hybrid.xml:93(para)
msgid "If the public cloud is AWS, the CMP would use the EC2 API to create a new instance and assign an Elastic IP. It can then add that IP to HAProxy in the private cloud. The CMP can also reference AWS-specific tools such as CloudWatch and CloudFormation."
msgstr ""

#: ./doc/arch-design/hybrid/section_prescriptive_examples_hybrid.xml:98(para)
msgid "Several open source tool kits for building CMPs are available and can handle this kind of translation. Examples include ManageIQ, jClouds, and JumpGate."
msgstr ""

#: ./doc/arch-design/hybrid/section_prescriptive_examples_hybrid.xml:104(title)
msgid "High availability and disaster recovery"
msgstr ""

#: ./doc/arch-design/hybrid/section_prescriptive_examples_hybrid.xml:105(para)
msgid "Company C requires their local data center to be able to recover from failure. Some of the workloads currently in use are running on their private OpenStack cloud. Protecting the data involves Block Storage, Object Storage, and a database. The architecture supports the failure of large components of the system while ensuring that the system continues to deliver services. While the services remain available to users, the failed components are restored in the background based on standard best practice data replication policies. To achieve these objectives, Company C replicates data to a second cloud in a geographically distant location. The following diagram describes this system:"
msgstr ""

#: ./doc/arch-design/hybrid/section_prescriptive_examples_hybrid.xml:124(para)
msgid "This example includes two private OpenStack clouds connected with a CMP. The source cloud, OpenStack Cloud 1, includes a controller and at least one instance running MySQL. It also includes at least one Block Storage volume and one Object Storage volume. This means that data is available to the users at all times. The details of the method for protecting each of these sources of data differs."
msgstr ""

#: ./doc/arch-design/hybrid/section_prescriptive_examples_hybrid.xml:132(para)
msgid "Object Storage relies on the replication capabilities of the Object Storage provider. Company C enables OpenStack Object Storage so that it creates geographically separated replicas that take advantage of this feature. The company configures storage so that at least one replica exists in each cloud. In order to make this work, the company configures a single array spanning both clouds with OpenStack Identity. Using Federated Identity, the array talks to both clouds, communicating with OpenStack Object Storage through the Swift proxy."
msgstr ""

#: ./doc/arch-design/hybrid/section_prescriptive_examples_hybrid.xml:141(para)
msgid "For Block Storage, the replication is a little more difficult, and involves tools outside of OpenStack itself. The OpenStack Block Storage volume is not set as the drive itself but as a logical object that points to a physical back end. Disaster recovery is configured for Block Storage for synchronous backup for the highest level of data protection, but asynchronous backup could have been set as an alternative that is not as latency sensitive. For asynchronous backup, the Block Storage API makes it possible to export the data and also the metadata of a particular volume, so that it can be moved and replicated elsewhere. More information can be found here: <link xlink:href=\"https://blueprints.launchpad.net/cinder/+spec/cinder-backup-volume-metadata-support\"> https://blueprints.launchpad.net/cinder/+spec/cinder-backup-volume-metadata-support</link>."
msgstr ""

#: ./doc/arch-design/hybrid/section_prescriptive_examples_hybrid.xml:156(para)
msgid "The synchronous backups create an identical volume in both clouds and chooses the appropriate flavor so that each cloud has an identical back end. This is done by creating volumes through the CMP. After this is configured, a solution involving DRDB synchronizes the physical drives."
msgstr ""

#: ./doc/arch-design/hybrid/section_prescriptive_examples_hybrid.xml:161(para)
msgid "The database component is backed up using synchronous backups. MySQL does not support geographically diverse replication, so disaster recovery is provided by replicating the file itself. As it is not possible to use Object Storage as the back end of a database like MySQL, Swift replication is not an option. Company C decides not to store the data on another geo-tiered storage system, such as Ceph, as Block Storage. This would have given another layer of protection. Another option would have been to store the database on an OpenStack Block Storage volume and backing it up like any other Block Storage."
msgstr ""

#: ./doc/arch-design/hybrid/section_architecture_hybrid.xml:9(para)
msgid "Map out the dependencies of the expected workloads and the cloud infrastructures required to support them to architect a solution for the broadest compatibility between cloud platforms, minimizing the need to create workarounds and processes to fill identified gaps."
msgstr ""

#: ./doc/arch-design/hybrid/section_architecture_hybrid.xml:14(para)
msgid "For your chosen cloud management platform, note the relative levels of support for both monitoring and orchestration."
msgstr ""

#: ./doc/arch-design/hybrid/section_architecture_hybrid.xml:25(para)
msgid "The majority of cloud workloads currently run on instances using hypervisor technologies. The challenge is that each of these hypervisors uses an image format that may not be compatible with the others. When possible, standardize on a single hypervisor and instance image format. This may not be possible when using externally-managed public clouds."
msgstr ""

#: ./doc/arch-design/hybrid/section_architecture_hybrid.xml:31(para)
msgid "Conversion tools exist to address image format compatibility. Examples include <link xlink:href=\"http://libguestfs.org/virt-v2v\">virt-p2v/virt-v2v</link> and <link xlink:href=\"http://libguestfs.org/virt-edit.1.html\"> virt-edit</link>. These tools cannot serve beyond basic cloud instance specifications."
msgstr ""

#: ./doc/arch-design/hybrid/section_architecture_hybrid.xml:38(para)
msgid "Alternatively, build a thin operating system image as the base for new instances. This facilitates rapid creation of cloud instances using cloud orchestration or configuration management tools for more specific templating. Remember if you intend to use portable images for disaster recovery, application diversity, or high availability, your users could move the images and instances between cloud platforms regularly."
msgstr ""

#: ./doc/arch-design/hybrid/section_architecture_hybrid.xml:48(title)
msgid "Upper-layer services"
msgstr ""

#: ./doc/arch-design/hybrid/section_architecture_hybrid.xml:49(para)
msgid "Many clouds offer complementary services beyond the basic compute, network, and storage components. These additional services often simplify the deployment and management of applications on a cloud platform."
msgstr ""

#: ./doc/arch-design/hybrid/section_architecture_hybrid.xml:53(para)
msgid "When moving workloads from the source to the destination cloud platforms, consider that the destination cloud platform may not have comparable services. Implement workloads in a different way or by using a different technology."
msgstr ""

#: ./doc/arch-design/hybrid/section_architecture_hybrid.xml:57(para)
msgid "For example, moving an application that uses a NoSQL database service such as MongoDB could cause difficulties in maintaining the application between the platforms."
msgstr ""

#: ./doc/arch-design/hybrid/section_architecture_hybrid.xml:60(para)
msgid "There are a number of options that are appropriate for the hybrid cloud use case:"
msgstr ""

#: ./doc/arch-design/hybrid/section_architecture_hybrid.xml:64(para)
msgid "Implementing a baseline of upper-layer services across all of the cloud platforms. For platforms that do not support a given service, create a service on top of that platform and apply it to the workloads as they are launched on that cloud."
msgstr ""

#: ./doc/arch-design/hybrid/section_architecture_hybrid.xml:69(para)
msgid "For example, through the <glossterm>Database service</glossterm> for OpenStack (<glossterm>trove</glossterm>), OpenStack supports MySQL-as-a-Service but not NoSQL databases in production. To move from or run alongside AWS, a NoSQL workload must use an automation tool, such as the Orchestration service (heat), to recreate the NoSQL database on top of OpenStack."
msgstr ""

#: ./doc/arch-design/hybrid/section_architecture_hybrid.xml:79(para)
msgid "Deploying a <glossterm>Platform-as-a-Service (PaaS)</glossterm> technology that abstracts the upper-layer services from the underlying cloud platform. The unit of application deployment and migration is the PaaS. It leverages the services of the PaaS and only consumes the base infrastructure services of the cloud platform."
msgstr ""

#: ./doc/arch-design/hybrid/section_architecture_hybrid.xml:88(para)
msgid "Using automation tools to create the required upper-layer services that are portable across all cloud platforms."
msgstr ""

#: ./doc/arch-design/hybrid/section_architecture_hybrid.xml:90(para)
msgid "For example, instead of using database services that are inherent in the cloud platforms, launch cloud instances and deploy the databases on those instances using scripts or configuration and application deployment tools."
msgstr ""

#: ./doc/arch-design/hybrid/section_architecture_hybrid.xml:100(title)
msgid "Network services"
msgstr ""

#: ./doc/arch-design/hybrid/section_architecture_hybrid.xml:101(para)
msgid "Network services functionality is a critical component of multiple cloud architectures. It is an important factor to assess when choosing a CMP and cloud provider. Considerations include:"
msgstr ""

#: ./doc/arch-design/hybrid/section_architecture_hybrid.xml:107(para)
msgid "Functionality"
msgstr ""

#: ./doc/arch-design/hybrid/section_architecture_hybrid.xml:122(para)
msgid "High availability (HA)"
msgstr ""

#: ./doc/arch-design/hybrid/section_architecture_hybrid.xml:127(para)
msgid "Verify and test critical cloud endpoint features."
msgstr ""

#: ./doc/arch-design/hybrid/section_architecture_hybrid.xml:130(para)
msgid "After selecting the network functionality framework, you must confirm the functionality is compatible. This ensures testing and functionality persists during and after upgrades."
msgstr ""

#: ./doc/arch-design/hybrid/section_architecture_hybrid.xml:135(para)
msgid "Diverse cloud platforms may de-synchronize over time if you do not maintain their mutual compatibility. This is a particular issue with APIs."
msgstr ""

#: ./doc/arch-design/hybrid/section_architecture_hybrid.xml:141(para)
msgid "Scalability across multiple cloud providers determines your choice of underlying network framework. It is important to have the network API functions presented and to verify that the desired functionality persists across all chosen cloud endpoint."
msgstr ""

#: ./doc/arch-design/hybrid/section_architecture_hybrid.xml:148(para)
msgid "High availability implementations vary in functionality and design. Examples of some common methods are active-hot-standby, active-passive, and active-active. Develop your high availability implementation and a test framework to understand the functionality and limitations of the environment."
msgstr ""

#: ./doc/arch-design/hybrid/section_architecture_hybrid.xml:156(para)
msgid "It is imperative to address security considerations. For example, addressing how data is secured between client and endpoint and any traffic that traverses the multiple clouds. Business and regulatory requirements dictate what security approach to take. For more information, see the <link linkend=\"security-overview\">Security Requirements Chapter</link>"
msgstr ""

#: ./doc/arch-design/hybrid/section_architecture_hybrid.xml:168(title) ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:666(para)
msgid "Data"
msgstr ""

#: ./doc/arch-design/hybrid/section_architecture_hybrid.xml:169(para)
msgid "Traditionally, replication has been the best method of protecting object store implementations. A variety of replication methods exist in storage architectures, for example synchronous and asynchronous mirroring. Most object stores and back-end storage systems implement methods for replication at the storage subsystem layer. Object stores also tailor replication techniques to fit a cloud's requirements."
msgstr ""

#: ./doc/arch-design/hybrid/section_architecture_hybrid.xml:176(para)
msgid "Organizations must find the right balance between data integrity and data availability. Replication strategy may also influence disaster recovery methods."
msgstr ""

#: ./doc/arch-design/hybrid/section_architecture_hybrid.xml:179(para)
msgid "Replication across different racks, data centers, and geographical regions increases focus on determining and ensuring data locality. The ability to guarantee data is accessed from the nearest or fastest storage can be necessary for applications to perform well."
msgstr ""

#: ./doc/arch-design/hybrid/section_architecture_hybrid.xml:185(para)
msgid "When running embedded object store methods, ensure that you do not instigate extra data replication as this can cause performance issues."
msgstr ""

#: ./doc/arch-design/introduction/section_intended_audience.xml:7(title)
msgid "Intended audience"
msgstr ""

#: ./doc/arch-design/introduction/section_intended_audience.xml:8(para)
msgid "This book has been written for architects and designers of OpenStack clouds. For a guide on deploying and operating OpenStack, please refer to the <citetitle>OpenStack Operations Guide</citetitle> (<link xlink:href=\"http://docs.openstack.org/openstack-ops\">http://docs.openstack.org/openstack-ops</link>)."
msgstr ""

#: ./doc/arch-design/introduction/section_intended_audience.xml:14(para)
msgid "Before reading this book, we recommend prior knowledge of cloud architecture and principles, experience in enterprise system design, Linux and virtualization experience, and a basic understanding of networking principles and protocols."
msgstr ""

#: ./doc/arch-design/introduction/section_methodology.xml:11(title)
msgid "Methodology"
msgstr ""

#: ./doc/arch-design/introduction/section_methodology.xml:12(para)
msgid "The best way to design your cloud architecture is through creating and testing use cases. Planning for applications that support thousands of sessions per second, variable workloads, and complex, changing data, requires you to identify the key meters. Identifying these key meters, such as number of concurrent transactions per second, and size of database, makes it possible to build a method for testing your assumptions."
msgstr ""

#: ./doc/arch-design/introduction/section_methodology.xml:18(para)
msgid "Use a functional user scenario to develop test cases, and to measure overall project trajectory."
msgstr ""

#: ./doc/arch-design/introduction/section_methodology.xml:21(para)
msgid "If you do not want to use an application to develop user requirements automatically, you need to create requirements to build test harnesses and develop usable meters."
msgstr ""

#: ./doc/arch-design/introduction/section_methodology.xml:25(para)
msgid "Establishing these meters allows you to respond to changes quickly without having to set exact requirements in advance. This creates ways to configure the system, rather than redesigning it every time there is a requirements change."
msgstr ""

#: ./doc/arch-design/introduction/section_methodology.xml:30(para)
msgid "It is important to limit scope creep. Ensure you address tool limitations, but do not recreate the entire suite of tools. Work with technical product owners to establish critical features that are needed for a successful cloud deployment."
msgstr ""

#: ./doc/arch-design/introduction/section_methodology.xml:37(title)
msgid "Application cloud readiness"
msgstr ""

#: ./doc/arch-design/introduction/section_methodology.xml:38(para)
msgid "The cloud does more than host virtual machines and their applications. This <emphasis>lift and shift</emphasis> approach works in certain situations, but there is a fundamental difference between clouds and traditional bare-metal-based environments, or even traditional virtualized environments."
msgstr ""

#: ./doc/arch-design/introduction/section_methodology.xml:43(para)
msgid "In traditional environments, with traditional enterprise applications, the applications and the servers that run on them are <emphasis>pets</emphasis>. They are lovingly crafted and cared for, the servers have names like Gandalf or Tardis, and if they get sick someone nurses them back to health. All of this is designed so that the application does not experience an outage."
msgstr ""

#: ./doc/arch-design/introduction/section_methodology.xml:50(para)
msgid "In cloud environments, servers are more like cattle. There are thousands of them, they get names like NY-1138-Q, and if they get sick, they get put down and a sysadmin installs another one. Traditional applications that are unprepared for this kind of environment may suffer outages, loss of data, or complete failure."
msgstr ""

#: ./doc/arch-design/introduction/section_methodology.xml:56(para)
msgid "There are other reasons to design applications with the cloud in mind. Some are defensive, such as the fact that because applications cannot be certain of exactly where or on what hardware they will be launched, they need to be flexible, or at least adaptable. Others are proactive. For example, one of the advantages of using the cloud is scalability. Applications need to be designed in such a way that they can take advantage of these and other opportunities."
msgstr ""

#: ./doc/arch-design/introduction/section_methodology.xml:66(title)
msgid "Determining whether an application is cloud-ready"
msgstr ""

#: ./doc/arch-design/introduction/section_methodology.xml:67(para)
msgid "There are several factors to take into consideration when looking at whether an application is a good fit for the cloud."
msgstr ""

#: ./doc/arch-design/introduction/section_methodology.xml:71(term)
msgid "Structure"
msgstr ""

#: ./doc/arch-design/introduction/section_methodology.xml:73(para)
msgid "A large, monolithic, single-tiered, legacy application typically is not a good fit for the cloud. Efficiencies are gained when load can be spread over several instances, so that a failure in one part of the system can be mitigated without affecting other parts of the system, or so that scaling can take place where the app needs it."
msgstr ""

#: ./doc/arch-design/introduction/section_methodology.xml:88(para)
msgid "Applications that depend on specific hardware, such as a particular chip set or an external device such as a fingerprint reader, might not be a good fit for the cloud, unless those dependencies are specifically addressed. Similarly, if an application depends on an operating system or set of libraries that cannot be used in the cloud, or cannot be virtualized, that is a problem."
msgstr ""

#: ./doc/arch-design/introduction/section_methodology.xml:104(para)
msgid "Self-contained applications, or those that depend on resources that are not reachable by the cloud in question, will not run. In some situations, you can work around these issues with custom network setup, but how well this works depends on the chosen cloud environment."
msgstr ""

#: ./doc/arch-design/introduction/section_methodology.xml:115(term)
msgid "Durability and resilience"
msgstr ""

#: ./doc/arch-design/introduction/section_methodology.xml:117(para)
msgid "Despite the existence of SLAs, things break: servers go down, network connections are disrupted, or too many tenants on a server make a server unusable. An application must be sturdy enough to contend with these issues."
msgstr ""

#: ./doc/arch-design/introduction/section_methodology.xml:130(title)
msgid "Designing for the cloud"
msgstr ""

#: ./doc/arch-design/introduction/section_methodology.xml:131(para)
msgid "Here are some guidelines to keep in mind when designing an application for the cloud:"
msgstr ""

#: ./doc/arch-design/introduction/section_methodology.xml:135(para)
msgid "Be a pessimist: Assume everything fails and design backwards."
msgstr ""

#: ./doc/arch-design/introduction/section_methodology.xml:139(para)
msgid "Put your eggs in multiple baskets: Leverage multiple providers, geographic regions and availability zones to accommodate for local availability issues. Design for portability."
msgstr ""

#: ./doc/arch-design/introduction/section_methodology.xml:145(para)
msgid "Think efficiency: Inefficient designs will not scale. Efficient designs become cheaper as they scale. Kill off unneeded components or capacity."
msgstr ""

#: ./doc/arch-design/introduction/section_methodology.xml:150(para)
msgid "Be paranoid: Design for defense in depth and zero tolerance by building in security at every level and between every component. Trust no one."
msgstr ""

#: ./doc/arch-design/introduction/section_methodology.xml:155(para)
msgid "But not too paranoid: Not every application needs the platinum solution. Architect for different SLA's, service tiers, and security levels."
msgstr ""

#: ./doc/arch-design/introduction/section_methodology.xml:160(para)
msgid "Manage the data: Data is usually the most inflexible and complex area of a cloud and cloud integration architecture. Do not short change the effort in analyzing and addressing data needs."
msgstr ""

#: ./doc/arch-design/introduction/section_methodology.xml:166(para)
msgid "Hands off: Leverage automation to increase consistency and quality and reduce response times."
msgstr ""

#: ./doc/arch-design/introduction/section_methodology.xml:170(para)
msgid "Divide and conquer: Pursue partitioning and parallel layering wherever possible. Make components as small and portable as possible. Use load balancing between layers."
msgstr ""

#: ./doc/arch-design/introduction/section_methodology.xml:176(para)
msgid "Think elasticity: Increasing resources should result in a proportional increase in performance and scalability. Decreasing resources should have the opposite effect."
msgstr ""

#: ./doc/arch-design/introduction/section_methodology.xml:182(para)
msgid "Be dynamic: Enable dynamic configuration changes such as auto scaling, failure recovery and resource discovery to adapt to changing environments, faults, and workload volumes."
msgstr ""

#: ./doc/arch-design/introduction/section_methodology.xml:188(para)
msgid "Stay close: Reduce latency by moving highly interactive components and data near each other."
msgstr ""

#: ./doc/arch-design/introduction/section_methodology.xml:192(para)
msgid "Keep it loose: Loose coupling, service interfaces, separation of concerns, abstraction, and well defined API's deliver flexibility."
msgstr ""

#: ./doc/arch-design/introduction/section_methodology.xml:197(para)
msgid "Be cost aware: Autoscaling, data transmission, virtual software licenses, reserved instances, and similar costs can rapidly increase monthly usage charges. Monitor usage closely."
msgstr ""

#: ./doc/arch-design/introduction/section_how_this_book_is_organized.xml:7(title)
msgid "How this book is organized"
msgstr ""

#: ./doc/arch-design/introduction/section_how_this_book_is_organized.xml:8(para)
msgid "This book examines some of the most common uses for OpenStack clouds, and explains the considerations for each use case. Cloud architects may use this book as a comprehensive guide by reading all of the use cases, but it is also possible to review only the chapters which pertain to a specific use case. The use cases covered in this guide include:"
msgstr ""

#: ./doc/arch-design/introduction/section_how_this_book_is_organized.xml:16(para)
msgid "<link linkend=\"generalpurpose\">General purpose</link>: Uses common components that address 80% of common use cases."
msgstr ""

#: ./doc/arch-design/introduction/section_how_this_book_is_organized.xml:22(para)
msgid "<link linkend=\"compute_focus\">Compute focused</link>: For compute intensive workloads such as high performance computing (HPC)."
msgstr ""

#: ./doc/arch-design/introduction/section_how_this_book_is_organized.xml:28(para)
msgid "<link linkend=\"storage_focus\">Storage focused</link>: For storage intensive workloads such as data analytics with parallel file systems."
msgstr ""

#: ./doc/arch-design/introduction/section_how_this_book_is_organized.xml:34(para)
msgid "<link linkend=\"network_focus\">Network focused</link>: For high performance and reliable networking, such as a <glossterm>content delivery network (CDN)</glossterm>."
msgstr ""

#: ./doc/arch-design/introduction/section_how_this_book_is_organized.xml:41(para)
msgid "<link linkend=\"multi_site\">Multi-site</link>: For applications that require multiple site deployments for geographical, reliability or data locality reasons."
msgstr ""

#: ./doc/arch-design/introduction/section_how_this_book_is_organized.xml:48(para)
msgid "<link linkend=\"hybrid\">Hybrid cloud</link>: Uses multiple disparate clouds connected either for failover, hybrid cloud bursting, or availability."
msgstr ""

#: ./doc/arch-design/introduction/section_how_this_book_is_organized.xml:55(para)
msgid "<link linkend=\"massively_scalable\">Massively scalable</link>: For cloud service providers or other large installations"
msgstr ""

#: ./doc/arch-design/introduction/section_how_this_book_is_organized.xml:63(para)
msgid "<link linkend=\"specialized\">Specialized cases</link>: Architectures that have not previously been covered in the defined use cases."
msgstr ""

#: ./doc/arch-design/introduction/section_how_this_book_was_written.xml:7(title)
msgid "Why and how we wrote this book"
msgstr ""

#: ./doc/arch-design/introduction/section_how_this_book_was_written.xml:8(para)
msgid "We wrote this book to guide you through designing an OpenStack cloud architecture. This guide identifies design considerations for common cloud use cases and provides examples."
msgstr ""

#: ./doc/arch-design/introduction/section_how_this_book_was_written.xml:11(para)
msgid "The Architecture Design Guide was written in a book sprint format, which is a facilitated, rapid development production method for books. The Book Sprint was facilitated by Faith Bosworth and Adam Hyde of Book Sprints, for more information, see the Book Sprints website (www.booksprints.net)."
msgstr ""

#: ./doc/arch-design/introduction/section_how_this_book_was_written.xml:16(para)
msgid "This book was written in five days during July 2014 while exhausting the M&amp;M, Mountain Dew and healthy options supply, complete with juggling entertainment during lunches at VMware's headquarters in Palo Alto."
msgstr ""

#: ./doc/arch-design/introduction/section_how_this_book_was_written.xml:20(para)
msgid "We would like to thank VMware for their generous hospitality, as well as our employers, Cisco, Cloudscaling, Comcast, EMC, Mirantis, Rackspace, Red Hat, Verizon, and VMware, for enabling us to contribute our time. We would especially like to thank Anne Gentle and Kenneth Hui for all of their shepherding and organization in making this happen."
msgstr ""

#: ./doc/arch-design/introduction/section_how_this_book_was_written.xml:27(para)
msgid "The author team includes:"
msgstr ""

#: ./doc/arch-design/introduction/section_how_this_book_was_written.xml:30(para)
msgid "Kenneth Hui (EMC) <link xlink:href=\"http://twitter.com/hui_kenneth\">@hui_kenneth</link>"
msgstr ""

#: ./doc/arch-design/introduction/section_how_this_book_was_written.xml:35(para)
msgid "Alexandra Settle (Rackspace) <link xlink:href=\"http://twitter.com/dewsday\">@dewsday</link>"
msgstr ""

#: ./doc/arch-design/introduction/section_how_this_book_was_written.xml:40(para)
msgid "Anthony Veiga (Comcast) <link xlink:href=\"http://twitter.com/daaelar\">@daaelar</link>"
msgstr ""

#: ./doc/arch-design/introduction/section_how_this_book_was_written.xml:45(para)
msgid "Beth Cohen (Verizon) <link xlink:href=\"http://twitter.com/bfcohen\">@bfcohen</link>"
msgstr ""

#: ./doc/arch-design/introduction/section_how_this_book_was_written.xml:50(para)
msgid "Kevin Jackson (Rackspace) <link xlink:href=\"http://twitter.com/itarchitectkev\">@itarchitectkev</link>"
msgstr ""

#: ./doc/arch-design/introduction/section_how_this_book_was_written.xml:55(para)
msgid "Maish Saidel-Keesing (Cisco) <link xlink:href=\"http://twitter.com/maishsk\">@maishsk</link>"
msgstr ""

#: ./doc/arch-design/introduction/section_how_this_book_was_written.xml:60(para)
msgid "Nick Chase (Mirantis) <link xlink:href=\"http://twitter.com/NickChase\">@NickChase</link>"
msgstr ""

#: ./doc/arch-design/introduction/section_how_this_book_was_written.xml:65(para)
msgid "Scott Lowe (VMware) <link xlink:href=\"http://twitter.com/scott_lowe\">@scott_lowe</link>"
msgstr ""

#: ./doc/arch-design/introduction/section_how_this_book_was_written.xml:70(para)
msgid "Sean Collins (Comcast) <link xlink:href=\"http://twitter.com/sc68cal\">@sc68cal</link>"
msgstr ""

#: ./doc/arch-design/introduction/section_how_this_book_was_written.xml:75(para)
msgid "Sean Winn (Cloudscaling) <link xlink:href=\"http://twitter.com/seanmwinn\">@seanmwinn</link>"
msgstr ""

#: ./doc/arch-design/introduction/section_how_this_book_was_written.xml:80(para)
msgid "Sebastian Gutierrez (Red Hat) <link xlink:href=\"http://twitter.com/gutseb\">@gutseb</link>"
msgstr ""

#: ./doc/arch-design/introduction/section_how_this_book_was_written.xml:85(para)
msgid "Stephen Gordon (Red Hat) <link xlink:href=\"http://twitter.com/xsgordon\">@xsgordon</link>"
msgstr ""

#: ./doc/arch-design/introduction/section_how_this_book_was_written.xml:90(para)
msgid "Vinny Valdez (Red Hat) <link xlink:href=\"http://twitter.com/VinnyValdez\">@VinnyValdez</link>"
msgstr ""

#. When image changes, this message will be marked fuzzy or untranslated for you.
#. It doesn't matter what you translate it to: it's not used at all.
#: ./doc/arch-design/specialized/section_desktop_as_a_service_specialized.xml:62(None)
msgid "@@image: '../figures/Specialized_VDI1.png'; md5=77729426d59881476de9a03e1ee8a22c"
msgstr ""

#: ./doc/arch-design/specialized/section_desktop_as_a_service_specialized.xml:8(title)
msgid "Desktop-as-a-Service"
msgstr ""

#: ./doc/arch-design/specialized/section_desktop_as_a_service_specialized.xml:9(para)
msgid "Virtual Desktop Infrastructure (VDI) is a service that hosts user desktop environments on remote servers. This application is very sensitive to network latency and requires a high performance compute environment. Traditionally these types of services do not use cloud environments because few clouds support such a demanding workload for user-facing applications. As cloud environments become more robust, vendors are starting to provide services that provide virtual desktops in the cloud. OpenStack may soon provide the infrastructure for these types of deployments."
msgstr ""

#: ./doc/arch-design/specialized/section_desktop_as_a_service_specialized.xml:21(title) ./doc/arch-design/specialized/section_software_defined_networking_specialized.xml:19(title) ./doc/arch-design/specialized/section_openstack_on_openstack_specialized.xml:25(title) ./doc/arch-design/specialized/section_networking_specialized.xml:15(title) ./doc/arch-design/specialized/section_hardware_specialized.xml:16(title)
msgid "Challenges"
msgstr ""

#: ./doc/arch-design/specialized/section_desktop_as_a_service_specialized.xml:22(para)
msgid "Designing an infrastructure that is suitable to host virtual desktops is a very different task to that of most virtual workloads. For example, the design must consider:"
msgstr ""

#: ./doc/arch-design/specialized/section_desktop_as_a_service_specialized.xml:27(para)
msgid "Boot storms, when a high volume of logins occur in a short period of time"
msgstr ""

#: ./doc/arch-design/specialized/section_desktop_as_a_service_specialized.xml:31(para)
msgid "The performance of the applications running on virtual desktops"
msgstr ""

#: ./doc/arch-design/specialized/section_desktop_as_a_service_specialized.xml:35(para)
msgid "Operating systems and their compatibility with the OpenStack hypervisor"
msgstr ""

#: ./doc/arch-design/specialized/section_desktop_as_a_service_specialized.xml:41(title)
msgid "Broker"
msgstr ""

#: ./doc/arch-design/specialized/section_desktop_as_a_service_specialized.xml:42(para)
msgid "The connection broker determines which remote desktop host users can access. Medium and large scale environments require a broker since its service represents a central component of the architecture. The broker is a complete management product, and enables automated deployment and provisioning of remote desktop hosts."
msgstr ""

#: ./doc/arch-design/specialized/section_desktop_as_a_service_specialized.xml:49(title) ./doc/arch-design/specialized/section_software_defined_networking_specialized.xml:28(title) ./doc/arch-design/specialized/section_networking_specialized.xml:23(title)
msgid "Possible solutions"
msgstr ""

#: ./doc/arch-design/specialized/section_desktop_as_a_service_specialized.xml:50(para)
msgid "There are a number of commercial products currently available that provide a broker solution. However, no native OpenStack projects provide broker services. Not providing a broker is also an option, but managing this manually would not suffice for a large scale, enterprise solution."
msgstr ""

#: ./doc/arch-design/specialized/section_desktop_as_a_service_specialized.xml:59(title) ./doc/arch-design/specialized/section_software_defined_networking_specialized.xml:40(title) ./doc/arch-design/specialized/section_openstack_on_openstack_specialized.xml:71(title)
msgid "Diagram"
msgstr ""

#. When image changes, this message will be marked fuzzy or untranslated for you.
#. It doesn't matter what you translate it to: it's not used at all.
#: ./doc/arch-design/specialized/section_software_defined_networking_specialized.xml:44(None)
msgid "@@image: '../figures/Special_case_SDN_hosted.png'; md5=93f5e5b90b5aea50d24a098ba80c805d"
msgstr ""

#. When image changes, this message will be marked fuzzy or untranslated for you.
#. It doesn't matter what you translate it to: it's not used at all.
#: ./doc/arch-design/specialized/section_software_defined_networking_specialized.xml:51(None)
msgid "@@image: '../figures/Special_case_SDN_external.png'; md5=12d9e840a0a10a5abcf1a2c1f6f80965"
msgstr ""

#: ./doc/arch-design/specialized/section_software_defined_networking_specialized.xml:8(title)
msgid "Software-defined networking"
msgstr ""

#: ./doc/arch-design/specialized/section_software_defined_networking_specialized.xml:9(para)
msgid "Software-defined networking (SDN) is the separation of the data plane and control plane. SDN is a popular method of managing and controlling packet flows within networks. SDN uses overlays or directly controlled layer-2 devices to determine flow paths, and as such presents challenges to a cloud environment. Some designers may wish to run their controllers within an OpenStack installation. Others may wish to have their installations participate in an SDN-controlled network."
msgstr ""

#: ./doc/arch-design/specialized/section_software_defined_networking_specialized.xml:20(para)
msgid "SDN is a relatively new concept that is not yet standardized, so SDN systems come in a variety of different implementations. Because of this, a truly prescriptive architecture is not feasible. Instead, examine the differences between an existing and a planned OpenStack design and determine where potential conflicts and gaps exist."
msgstr ""

#: ./doc/arch-design/specialized/section_software_defined_networking_specialized.xml:29(para)
msgid "If an SDN implementation requires layer-2 access because it directly manipulates switches, we do not recommend running an overlay network or a layer-3 agent. If the controller resides within an OpenStack installation, it may be necessary to build an ML2 plug-in and schedule the controller instances to connect to tenant VLANs that then talk directly to the switch hardware. Alternatively, depending on the external device support, use a tunnel that terminates at the switch hardware itself."
msgstr ""

#: ./doc/arch-design/specialized/section_software_defined_networking_specialized.xml:41(para)
msgid "OpenStack hosted SDN controller: <placeholder-1/>"
msgstr ""

#: ./doc/arch-design/specialized/section_software_defined_networking_specialized.xml:48(para)
msgid "OpenStack participating in an SDN controller network: <placeholder-1/>"
msgstr ""

#. When image changes, this message will be marked fuzzy or untranslated for you.
#. It doesn't matter what you translate it to: it's not used at all.
#: ./doc/arch-design/specialized/section_openstack_on_openstack_specialized.xml:75(None)
msgid "@@image: '../figures/Specialized_OOO.png'; md5=65a8e3666ebf09a0145c61bc1d472144"
msgstr ""

#: ./doc/arch-design/specialized/section_openstack_on_openstack_specialized.xml:12(title)
msgid "OpenStack on OpenStack"
msgstr ""

#: ./doc/arch-design/specialized/section_openstack_on_openstack_specialized.xml:13(para)
msgid "In some cases, users may run OpenStack nested on top of another OpenStack cloud. This scenario describes how to manage and provision complete OpenStack environments on instances supported by hypervisors and servers, which an underlying OpenStack environment controls."
msgstr ""

#: ./doc/arch-design/specialized/section_openstack_on_openstack_specialized.xml:18(para)
msgid "Public cloud providers can use this technique to manage the upgrade and maintenance process on complete OpenStack environments. Developers and those testing OpenStack can also use this technique to provision their own OpenStack environments on available OpenStack Compute resources, whether public or private."
msgstr ""

#: ./doc/arch-design/specialized/section_openstack_on_openstack_specialized.xml:26(para)
msgid "The network aspect of deploying a nested cloud is the most complicated aspect of this architecture. You must expose VLANs to the physical ports on which the underlying cloud runs because the bare metal cloud owns all the hardware. You must also expose them to the nested levels as well. Alternatively, you can use the network overlay technologies on the OpenStack environment running on the host OpenStack environment to provide the required software defined networking for the deployment."
msgstr ""

#: ./doc/arch-design/specialized/section_openstack_on_openstack_specialized.xml:37(title) ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:361(title)
msgid "Hypervisor"
msgstr ""

#: ./doc/arch-design/specialized/section_openstack_on_openstack_specialized.xml:38(para)
msgid "In this example architecture, consider which approach you should take to provide a nested hypervisor in OpenStack. This decision influences which operating systems you use for the deployment of the nested OpenStack deployments."
msgstr ""

#: ./doc/arch-design/specialized/section_openstack_on_openstack_specialized.xml:45(title)
msgid "Possible solutions: deployment"
msgstr ""

#: ./doc/arch-design/specialized/section_openstack_on_openstack_specialized.xml:46(para)
msgid "Deployment of a full stack can be challenging but you can mitigate this difficulty by creating a Heat template to deploy the entire stack, or a configuration management system. After creating the Heat template, you can automate the deployment of additional stacks."
msgstr ""

#: ./doc/arch-design/specialized/section_openstack_on_openstack_specialized.xml:50(para)
msgid "The OpenStack-on-OpenStack project (<glossterm>TripleO</glossterm>) addresses this issue. Currently, however, the project does not completely cover nested stacks. For more information, see <link xlink:href=\"https://wiki.openstack.org/wiki/TripleO\"> https://wiki.openstack.org/wiki/TripleO</link>."
msgstr ""

#: ./doc/arch-design/specialized/section_openstack_on_openstack_specialized.xml:57(title)
msgid "Possible solutions: hypervisor"
msgstr ""

#: ./doc/arch-design/specialized/section_openstack_on_openstack_specialized.xml:58(para)
msgid "In the case of running TripleO, the underlying OpenStack cloud deploys the Compute nodes as bare-metal. You then deploy OpenStack on these Compute bare-metal servers with the appropriate hypervisor, such as KVM."
msgstr ""

#: ./doc/arch-design/specialized/section_openstack_on_openstack_specialized.xml:62(para)
msgid "In the case of running smaller OpenStack clouds for testing purposes, where performance is not a critical factor, you can use QEMU instead. It is also possible to run a KVM hypervisor in an instance (see <link xlink:href=\"http://davejingtian.org/2014/03/30/nested-kvm-just-for-fun/\"> http://davejingtian.org/2014/03/30/nested-kvm-just-for-fun/</link>), though this is not a supported configuration, and could be a complex solution for such a use case."
msgstr ""

#: ./doc/arch-design/specialized/section_networking_specialized.xml:8(title)
msgid "Specialized networking example"
msgstr ""

#: ./doc/arch-design/specialized/section_networking_specialized.xml:9(para)
msgid "Some applications that interact with a network require specialized connectivity. Applications such as a looking glass require the ability to connect to a BGP peer, or route participant applications may need to join a network at a layer 2 level."
msgstr ""

#: ./doc/arch-design/specialized/section_networking_specialized.xml:16(para)
msgid "Connecting specialized network applications to their required resources alters the design of an OpenStack installation. Installations that rely on overlay networks are unable to support a routing participant, and may also block layer-2 listeners."
msgstr ""

#: ./doc/arch-design/specialized/section_networking_specialized.xml:24(para)
msgid "Deploying an OpenStack installation using OpenStack Networking with a provider network allows direct layer-2 connectivity to an upstream networking device. This design provides the layer-2 connectivity required to communicate via Intermediate System-to-Intermediate System (ISIS) protocol or to pass packets controlled by an OpenFlow controller. Using the multiple layer-2 plug-in with an agent such as <glossterm>Open vSwitch</glossterm> allows a private connection through a VLAN directly to a specific port in a layer-3 device. This allows a BGP point-to-point link to join the autonomous system. Avoid using layer-3 plug-ins as they divide the broadcast domain and prevent router adjacencies from forming."
msgstr ""

#. When image changes, this message will be marked fuzzy or untranslated for you.
#. It doesn't matter what you translate it to: it's not used at all.
#: ./doc/arch-design/specialized/section_hardware_specialized.xml:48(None)
msgid "@@image: '../figures/Specialized_Hardware2.png'; md5=f8477d5d015f4c6d4fcd56d511f14ef9"
msgstr ""

#: ./doc/arch-design/specialized/section_hardware_specialized.xml:8(title)
msgid "Specialized hardware"
msgstr ""

#: ./doc/arch-design/specialized/section_hardware_specialized.xml:9(para)
msgid "Certain workloads require specialized hardware devices that have significant virtualization or sharing challenges. Applications such as load balancers, highly parallel brute force computing, and direct to wire networking may need capabilities that basic OpenStack components do not provide."
msgstr ""

#: ./doc/arch-design/specialized/section_hardware_specialized.xml:17(para)
msgid "Some applications need access to hardware devices to either improve performance or provide capabilities that are not virtual CPU, RAM, network, or storage. These can be a shared resource, such as a cryptography processor, or a dedicated resource, such as a Graphics Processing Unit (GPU). OpenStack can provide some of these, while others may need extra work."
msgstr ""

#: ./doc/arch-design/specialized/section_hardware_specialized.xml:26(title)
msgid "Solutions"
msgstr ""

#: ./doc/arch-design/specialized/section_hardware_specialized.xml:27(para)
msgid "To provide cryptography offloading to a set of instances, you can use Image service configuration options. For example, assign the cryptography chip to a device node in the guest. The <citetitle>OpenStack Command Line Reference</citetitle> contains further information on configuring this solution in the chapter <link xlink:href=\"http://docs.openstack.org/cli-reference/content/chapter_cli-glance-property.html\"> Image service property keys</link>. A challenge, however, is this option allows all guests using the configured images to access the hypervisor cryptography device."
msgstr ""

#: ./doc/arch-design/specialized/section_hardware_specialized.xml:37(para)
msgid "If you require direct access to a specific device, PCI pass-through enables you to dedicate the device to a single instance per hypervisor. You must define a flavor that has the PCI device specifically in order to properly schedule instances. More information regarding PCI pass-through, including instructions for implementing and using it, is available at <link xlink:href=\"https://wiki.openstack.org/wiki/Pci_passthrough#How_to_check_PCI_status_with_PCI_api_patches\"> https://wiki.openstack.org/wiki/Pci_passthrough</link>."
msgstr ""

#. When image changes, this message will be marked fuzzy or untranslated for you.
#. It doesn't matter what you translate it to: it's not used at all.
#: ./doc/arch-design/specialized/section_multi_hypervisor_specialized.xml:23(None)
msgid "@@image: '../figures/Compute_NSX.png'; md5=1745487faf16b74b13f80ffd837f43a0"
msgstr ""

#: ./doc/arch-design/specialized/section_multi_hypervisor_specialized.xml:8(title)
msgid "Multi-hypervisor example"
msgstr ""

#: ./doc/arch-design/specialized/section_multi_hypervisor_specialized.xml:9(para)
msgid "A financial company requires its applications migrated from a traditional, virtualized environment to an API driven, orchestrated environment. The new environment needs multiple hypervisors since many of the company's applications have strict hypervisor requirements."
msgstr ""

#: ./doc/arch-design/specialized/section_multi_hypervisor_specialized.xml:14(para)
msgid "Currently, the company's vSphere environment runs 20 VMware ESXi hypervisors. These hypervisors support 300 instances of various sizes. Approximately 50 of these instances must run on ESXi. The remaining 250 or so have more flexible requirements."
msgstr ""

#: ./doc/arch-design/specialized/section_multi_hypervisor_specialized.xml:19(para)
msgid "The financial company decides to manage the overall system with a common OpenStack platform."
msgstr ""

#: ./doc/arch-design/specialized/section_multi_hypervisor_specialized.xml:26(para)
msgid "Architecture planning teams decided to run a host aggregate containing KVM hypervisors for the general purpose instances. A separate host aggregate targets instances requiring ESXi."
msgstr ""

#: ./doc/arch-design/specialized/section_multi_hypervisor_specialized.xml:29(para)
msgid "Images in the OpenStack Image service have particular hypervisor metadata attached. When a user requests a certain image, the instance spawns on the relevant aggregate."
msgstr ""

#: ./doc/arch-design/specialized/section_multi_hypervisor_specialized.xml:33(para)
msgid "Images for ESXi use the VMDK format. You can convert QEMU disk images to VMDK, VMFS Flat Disks. These disk images can also be thin, thick, zeroed-thick, and eager-zeroed-thick. After exporting a VMFS thin disk from VMFS to the OpenStack Image service (a non-VMFS location), it becomes a preallocated flat disk. This impacts the transfer time from the OpenStack Image service to the data store since transfers require moving the full preallocated flat disk rather than the thin disk."
msgstr ""

#: ./doc/arch-design/specialized/section_multi_hypervisor_specialized.xml:42(para)
msgid "The VMware host aggregate compute nodes communicate with vCenter rather than spawning directly on a hypervisor. The vCenter then requests scheduling for the instance to run on an ESXi hypervisor."
msgstr ""

#: ./doc/arch-design/specialized/section_multi_hypervisor_specialized.xml:46(para)
msgid "This functionality requires that VMware Distributed Resource Scheduler (DRS) is enabled on a cluster and set to <guilabel>Fully Automated</guilabel>. The vSphere requires shared storage because the DRS uses vMotion, which is a service that relies on shared storage."
msgstr ""

#: ./doc/arch-design/specialized/section_multi_hypervisor_specialized.xml:50(para)
msgid "This solution to the company's migration uses shared storage to provide Block Storage capabilities to the KVM instances while also providing vSphere storage. The new environment provides this storage functionality using a dedicated data network. The compute hosts should have dedicated NICs to support the dedicated data network. vSphere supports OpenStack Block Storage. This support gives storage from a VMFS datastore to an instance. For the financial company, Block Storage in their new architecture supports both hypervisors."
msgstr ""

#: ./doc/arch-design/specialized/section_multi_hypervisor_specialized.xml:59(para)
msgid "OpenStack Networking provides network connectivity in this new architecture, with the VMware NSX plug-in driver configured. legacy networking (nova-network) supports both hypervisors in this new architecture example, but has limitations. Specifically, vSphere with legacy networking does not support security groups. The new architecture uses VMware NSX as a part of the design. When users launch an instance within either of the host aggregates, VMware NSX ensures the instance attaches to the appropriate network overlay-based logical networks."
msgstr ""

#: ./doc/arch-design/specialized/section_multi_hypervisor_specialized.xml:68(para)
msgid "The architecture planning teams also consider OpenStack Compute integration. When running vSphere in an OpenStack environment, nova-compute communications with vCenter appear as a single large hypervisor. This hypervisor represents the entire ESXi cluster. Multiple nova-compute instances can represent multiple ESXi clusters. They can connect to multiple vCenter servers. If the process running nova-compute crashes it cuts the connection to the vCenter server. Any ESXi clusters will stop running, and you will not be able to provision further instances on the vCenter, even if you enable high availability. You must monitor the nova-compute service connected to vSphere carefully for any distruptions as a result of this failure point."
msgstr ""

#: ./doc/arch-design/massively_scalable/section_user_requirements_massively_scalable.xml:9(para)
msgid "Defining user requirements for a massively scalable OpenStack design architecture dictates approaching the design from two different, yet sometimes opposing, perspectives: the cloud user, and the cloud operator. The expectations and perceptions of the consumption and management of resources of a massively scalable OpenStack cloud from these two perspectives are distinctly different."
msgstr ""

#: ./doc/arch-design/massively_scalable/section_user_requirements_massively_scalable.xml:16(para)
msgid "Massively scalable OpenStack clouds have the following user requirements:"
msgstr ""

#: ./doc/arch-design/massively_scalable/section_user_requirements_massively_scalable.xml:20(para)
msgid "The cloud user expects repeatable, dependable, and deterministic processes for launching and deploying cloud resources. You could deliver this through a web-based interface or publicly available API endpoints. All appropriate options for requesting cloud resources must be available through some type of user interface, a command-line interface (CLI), or API endpoints."
msgstr ""

#: ./doc/arch-design/massively_scalable/section_user_requirements_massively_scalable.xml:30(para)
msgid "Cloud users expect a fully self-service and on-demand consumption model. When an OpenStack cloud reaches the \"massively scalable\" size, expect consumption \"as a service\" in each and every way."
msgstr ""

#: ./doc/arch-design/massively_scalable/section_user_requirements_massively_scalable.xml:37(para)
msgid "For a user of a massively scalable OpenStack public cloud, there are no expectations for control over security, performance, or availability. Users expect only SLAs related to uptime of API services, and very basic SLAs for services offered. It is the user's responsibility to address these issues on their own. The exception to this expectation is the rare case of a massively scalable cloud infrastructure built for a private or government organization that has specific requirements."
msgstr ""

#: ./doc/arch-design/massively_scalable/section_user_requirements_massively_scalable.xml:49(para)
msgid "The cloud user's requirements and expectations that determine the cloud design focus on the consumption model. The user expects to consume cloud resources in an automated and deterministic way, without any need for knowledge of the capacity, scalability, or other attributes of the cloud's underlying infrastructure."
msgstr ""

#: ./doc/arch-design/massively_scalable/section_user_requirements_massively_scalable.xml:56(title)
msgid "Operator requirements"
msgstr ""

#: ./doc/arch-design/massively_scalable/section_user_requirements_massively_scalable.xml:57(para)
msgid "While the cloud user can be completely unaware of the underlying infrastructure of the cloud and its attributes, the operator must build and support the infrastructure for operating at scale. This presents a very demanding set of requirements for building such a cloud from the operator's perspective:"
msgstr ""

#: ./doc/arch-design/massively_scalable/section_user_requirements_massively_scalable.xml:64(para)
msgid "Everything must be capable of automation. For example, everything from compute hardware, storage hardware, networking hardware, to the installation and configuration of the supporting software. Manual processes are impractical in a massively scalable OpenStack design architecture."
msgstr ""

#: ./doc/arch-design/massively_scalable/section_user_requirements_massively_scalable.xml:72(para)
msgid "The cloud operator requires that capital expenditure (CapEx) is minimized at all layers of the stack. Operators of massively scalable OpenStack clouds require the use of dependable commodity hardware and freely available open source software components to reduce deployment costs and operational expenses. Initiatives like OpenCompute (more information available at <link xlink:href=\"http://www.opencompute.org\">http://www.opencompute.org</link>) provide additional information and pointers. To cut costs, many operators sacrifice redundancy. For example, using redundant power supplies, network connections, and rack switches."
msgstr ""

#: ./doc/arch-design/massively_scalable/section_user_requirements_massively_scalable.xml:87(para)
msgid "Companies operating a massively scalable OpenStack cloud also require that operational expenditures (OpEx) be minimized as much as possible. We recommend using cloud-optimized hardware when managing operational overhead. Some of the factors to consider include power, cooling, and the physical design of the chassis. Through customization, it is possible to optimize the hardware and systems for this type of workload because of the scale of these implementations."
msgstr ""

#: ./doc/arch-design/massively_scalable/section_user_requirements_massively_scalable.xml:99(para)
msgid "Massively scalable OpenStack clouds require extensive metering and monitoring functionality to maximize the operational efficiency by keeping the operator informed about the status and state of the infrastructure. This includes full scale metering of the hardware and software status. A corresponding framework of logging and alerting is also required to store and enable operations to act on the meters provided by the metering and monitoring solutions. The cloud operator also needs a solution that uses the data provided by the metering and monitoring solution to provide capacity planning and capacity trending analysis."
msgstr ""

#: ./doc/arch-design/massively_scalable/section_user_requirements_massively_scalable.xml:114(para)
msgid "Invariably, massively scalable OpenStack clouds extend over several sites. Therefore, the user-operator requirements for a multi-site OpenStack architecture design are also applicable here. This includes various legal requirements; other jurisdictional legal or compliance requirements; image consistency-availability; storage replication and availability (both block and file/object storage); and authentication, authorization, and auditing (AAA). See <xref linkend=\"multi_site\"/> for more details on requirements and considerations for multi-site OpenStack clouds."
msgstr ""

#: ./doc/arch-design/massively_scalable/section_user_requirements_massively_scalable.xml:128(para)
msgid "The design architecture of a massively scalable OpenStack cloud must address considerations around physical facilities such as space, floor weight, rack height and type, environmental considerations, power usage and power usage efficiency (PUE), and physical security."
msgstr ""

#: ./doc/arch-design/massively_scalable/section_operational_considerations_massively_scalable.xml:9(para)
msgid "In order to run efficiently at massive scale, automate as many of the operational processes as possible. Automation includes the configuration of provisioning, monitoring and alerting systems. Part of the automation process includes the capability to determine when human intervention is required and who should act. The objective is to increase the ratio of operational staff to running systems as much as possible in order to reduce maintenance costs. In a massively scaled environment, it is very difficult for staff to give each system individual care."
msgstr ""

#: ./doc/arch-design/massively_scalable/section_operational_considerations_massively_scalable.xml:19(para)
msgid "Configuration management tools such as Puppet and Chef enable operations staff to categorize systems into groups based on their roles and thus create configurations and system states that the provisioning system enforces. Systems that fall out of the defined state due to errors or failures are quickly removed from the pool of active nodes and replaced."
msgstr ""

#: ./doc/arch-design/massively_scalable/section_operational_considerations_massively_scalable.xml:26(para)
msgid "At large scale the resource cost of diagnosing failed individual systems is far greater than the cost of replacement. It is more economical to replace the failed system with a new system, provisioning and configuring it automatically and adding it to the pool of active nodes. By automating tasks that are labor-intensive, repetitive, and critical to operations, cloud operations teams can work more efficiently because fewer resources are required for these common tasks. Administrators are then free to tackle tasks that are not easy to automate and that have longer-term impacts on the business, for example, capacity planning."
msgstr ""

#: ./doc/arch-design/massively_scalable/section_operational_considerations_massively_scalable.xml:39(title)
msgid "The bleeding edge"
msgstr ""

#: ./doc/arch-design/massively_scalable/section_operational_considerations_massively_scalable.xml:40(para)
msgid "Running OpenStack at massive scale requires striking a balance between stability and features. For example, it might be tempting to run an older stable release branch of OpenStack to make deployments easier. However, when running at massive scale, known issues that may be of some concern or only have minimal impact in smaller deployments could become pain points. Recent releases may address well known issues. The OpenStack community can help resolve reported issues by applying the collective expertise of the OpenStack developers."
msgstr ""

#: ./doc/arch-design/massively_scalable/section_operational_considerations_massively_scalable.xml:49(para)
msgid "The number of organizations running at massive scales is a small proportion of the OpenStack community, therefore it is important to share related issues with the community and be a vocal advocate for resolving them. Some issues only manifest when operating at large scale, and the number of organizations able to duplicate and validate an issue is small, so it is important to document and dedicate resources to their resolution."
msgstr ""

#: ./doc/arch-design/massively_scalable/section_operational_considerations_massively_scalable.xml:57(para)
msgid "In some cases, the resolution to the problem is ultimately to deploy a more recent version of OpenStack. Alternatively, when you must resolve an issue in a production environment where rebuilding the entire environment is not an option, it is sometimes possible to deploy updates to specific underlying components in order to resolve issues or gain significant performance improvements. Although this may appear to expose the deployment to increased risk and instability, in many cases it could be an undiscovered issue."
msgstr ""

#: ./doc/arch-design/massively_scalable/section_operational_considerations_massively_scalable.xml:67(para)
msgid "We recommend building a development and operations organization that is responsible for creating desired features, diagnosing and resolving issues, and building the infrastructure for large scale continuous integration tests and continuous deployment. This helps catch bugs early and makes deployments faster and easier. In addition to development resources, we also recommend the recruitment of experts in the fields of message queues, databases, distributed systems, networking, cloud, and storage."
msgstr ""

#: ./doc/arch-design/massively_scalable/section_operational_considerations_massively_scalable.xml:77(title)
msgid "Growth and capacity planning"
msgstr ""

#: ./doc/arch-design/massively_scalable/section_operational_considerations_massively_scalable.xml:78(para)
msgid "An important consideration in running at massive scale is projecting growth and utilization trends in order to plan capital expenditures for the short and long term. Gather utilization meters for compute, network, and storage, along with historical records of these meters. While securing major anchor tenants can lead to rapid jumps in the utilization rates of all resources, the steady adoption of the cloud inside an organization or by consumers in a public offering also creates a steady trend of increased utilization."
msgstr ""

#: ./doc/arch-design/massively_scalable/section_operational_considerations_massively_scalable.xml:89(title)
msgid "Skills and training"
msgstr ""

#: ./doc/arch-design/massively_scalable/section_operational_considerations_massively_scalable.xml:90(para)
msgid "Projecting growth for storage, networking, and compute is only one aspect of a growth plan for running OpenStack at massive scale. Growing and nurturing development and operational staff is an additional consideration. Sending team members to OpenStack conferences, meetup events, and encouraging active participation in the mailing lists and committees is a very important way to maintain skills and forge relationships in the community. For a list of OpenStack training providers in the marketplace, see: <link xlink:href=\"http://www.openstack.org/marketplace/training/\">http://www.openstack.org/marketplace/training/</link>."
msgstr ""

#. When image changes, this message will be marked fuzzy or untranslated for you.
#. It doesn't matter what you translate it to: it's not used at all.
#: ./doc/arch-design/massively_scalable/section_tech_considerations_massively_scalable.xml:128(None)
msgid "@@image: '../figures/Massively_Scalable_Cells_+_regions_+_azs.png'; md5=87d08365fefde431d6d055daf17d7d0e"
msgstr ""

#: ./doc/arch-design/massively_scalable/section_tech_considerations_massively_scalable.xml:13(para)
msgid "Repurposing an existing OpenStack environment to be massively scalable is a formidable task. When building a massively scalable environment from the ground up, ensure you build the initial deployment with the same principles and choices that apply as the environment grows. For example, a good approach is to deploy the first site as a multi-site environment. This enables you to use the same deployment and segregation methods as the environment grows to separate locations across dedicated links or wide area networks. In a hyperscale cloud, scale trumps redundancy. Modify applications with this in mind, relying on the scale and homogeneity of the environment to provide reliability rather than redundant infrastructure provided by non-commodity hardware solutions."
msgstr ""

#: ./doc/arch-design/massively_scalable/section_tech_considerations_massively_scalable.xml:28(title)
msgid "Infrastructure segregation"
msgstr ""

#: ./doc/arch-design/massively_scalable/section_tech_considerations_massively_scalable.xml:29(para)
msgid "OpenStack services support massive horizontal scale. Be aware that this is not the case for the entire supporting infrastructure. This is particularly a problem for the database management systems and message queues that OpenStack services use for data storage and remote procedure call communications."
msgstr ""

#: ./doc/arch-design/massively_scalable/section_tech_considerations_massively_scalable.xml:34(para)
msgid "Traditional clustering techniques typically provide high availability and some additional scale for these environments. In the quest for massive scale, however, you must take additional steps to relieve the performance pressure on these components in order to prevent them from negatively impacting the overall performance of the environment. Ensure that all the components are in balance so that if the massively scalable environment fails, all the components are near maximum capacity and a single component is not causing the failure."
msgstr ""

#: ./doc/arch-design/massively_scalable/section_tech_considerations_massively_scalable.xml:43(para)
msgid "Regions segregate completely independent installations linked only by an Identity and Dashboard (optional) installation. Services have separate API endpoints for each region, and include separate database and queue installations. This exposes some awareness of the environment's fault domains to users and gives them the ability to ensure some degree of application resiliency while also imposing the requirement to specify which region to apply their actions to."
msgstr ""

#: ./doc/arch-design/massively_scalable/section_tech_considerations_massively_scalable.xml:52(para)
msgid "Environments operating at massive scale typically need their regions or sites subdivided further without exposing the requirement to specify the failure domain to the user. This provides the ability to further divide the installation into failure domains while also providing a logical unit for maintenance and the addition of new hardware. At hyperscale, instead of adding single compute nodes, administrators can add entire racks or even groups of racks at a time with each new addition of nodes exposed via one of the segregation concepts mentioned herein."
msgstr ""

#: ./doc/arch-design/massively_scalable/section_tech_considerations_massively_scalable.xml:62(para)
msgid "<glossterm baseform=\"cell\">Cells</glossterm> provide the ability to subdivide the compute portion of an OpenStack installation, including regions, while still exposing a single endpoint. Each region has an API cell along with a number of compute cells where the workloads actually run. Each cell has its own database and message queue setup (ideally clustered), providing the ability to subdivide the load on these subsystems, improving overall performance."
msgstr ""

#: ./doc/arch-design/massively_scalable/section_tech_considerations_massively_scalable.xml:71(para)
msgid "Each compute cell provides a complete compute installation, complete with full database and queue installations, scheduler, conductor, and multiple compute hosts. The cells scheduler handles placement of user requests from the single API endpoint to a specific cell from those available. The normal filter scheduler then handles placement within the cell."
msgstr ""

#: ./doc/arch-design/massively_scalable/section_tech_considerations_massively_scalable.xml:78(para)
msgid "Unfortunately, Compute is the only OpenStack service that provides good support for cells. In addition, cells do not adequately support some standard OpenStack functionality such as security groups and host aggregates. Due to their relative newness and specialized use, cells receive relatively little testing in the OpenStack gate. Despite these issues, cells play an important role in well known OpenStack installations operating at massive scale, such as those at CERN and Rackspace."
msgstr ""

#: ./doc/arch-design/massively_scalable/section_tech_considerations_massively_scalable.xml:88(title)
msgid "Host aggregates"
msgstr ""

#: ./doc/arch-design/massively_scalable/section_tech_considerations_massively_scalable.xml:89(para)
msgid "Host aggregates enable partitioning of OpenStack Compute deployments into logical groups for load balancing and instance distribution. You can also use host aggregates to further partition an availability zone. Consider a cloud which might use host aggregates to partition an availability zone into groups of hosts that either share common resources, such as storage and network, or have a special property, such as trusted computing hardware. You cannot target host aggregates explicitly. Instead, select instance flavors that map to host aggregate metadata. These flavors target host aggregates implicitly."
msgstr ""

#: ./doc/arch-design/massively_scalable/section_tech_considerations_massively_scalable.xml:101(title)
msgid "Availability zones"
msgstr ""

#: ./doc/arch-design/massively_scalable/section_tech_considerations_massively_scalable.xml:102(para)
msgid "Availability zones provide another mechanism for subdividing an installation or region. They are, in effect, host aggregates exposed for (optional) explicit targeting by users."
msgstr ""

#: ./doc/arch-design/massively_scalable/section_tech_considerations_massively_scalable.xml:106(para)
msgid "Unlike cells, availability zones do not have their own database server or queue broker but represent an arbitrary grouping of compute nodes. Typically, nodes are grouped into availability zones using a shared failure domain based on a physical characteristic such as a shared power source or physical network connections. Users can target exposed availability zones; however, this is not a requirement. An alternative approach is to set a default availability zone to schedule instances to a non-default availability zone of <literal>nova</literal>."
msgstr ""

#: ./doc/arch-design/massively_scalable/section_tech_considerations_massively_scalable.xml:116(title)
msgid "Segregation example"
msgstr ""

#: ./doc/arch-design/massively_scalable/section_tech_considerations_massively_scalable.xml:117(para)
msgid "In this example the cloud is divided into two regions, one for each site, with two availability zones in each based on the power layout of the data centers. A number of host aggregates enable targeting of virtual machine instances using flavors, that require special capabilities shared by the target hosts such as SSDs, 10GbE networks, or GPU cards."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:13(para)
msgid "Hardware selection involves three key areas:"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:25(para)
msgid "Hardware for a general purpose OpenStack cloud should reflect a cloud with no pre-defined usage model, designed to run a wide variety of applications with varying resource usage requirements. These applications include any of the following:"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:32(para)
msgid "RAM-intensive"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:37(para)
msgid "CPU-intensive"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:42(para)
msgid "Storage-intensive"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:47(para)
msgid "Certain hardware form factors may better suit a general purpose OpenStack cloud due to the requirement for equal (or nearly equal) balance of resources. Server hardware must provide the following:"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:53(para)
msgid "Equal (or nearly equal) balance of compute capacity (RAM and CPU)"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:58(para)
msgid "Network capacity (number and speed of links)"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:63(para)
msgid "Storage capacity (gigabytes or terabytes as well as Input/Output Operations Per Second (<glossterm>IOPS</glossterm>)"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:69(para)
msgid "Evaluate server hardware around four conflicting dimensions:"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:83(para)
msgid "The number of CPU cores, amount of RAM, or amount of deliverable storage."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:90(para)
msgid "Limit of additional resources you can add to a server."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:97(para)
msgid "The relative purchase price of the hardware weighted against the level of design effort needed to build the system."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:103(para)
msgid "Increasing server density means sacrificing resource capacity or expandability, however, increasing resource capacity and expandability increases cost and decreases server density. As a result, determining the best server hardware for a general purpose OpenStack architecture means understanding how choice of form factor will impact the rest of the design. The following list outlines the form factors to choose from:"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:113(para)
msgid "Blade servers typically support dual-socket multi-core CPUs. Blades also offer outstanding density."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:118(para)
msgid "1U rack-mounted servers occupy only a single rack unit. Their benefits include high density, support for dual-socket multi-core CPUs, and support for reasonable RAM amounts. This form factor offers limited storage capacity, limited network capacity, and limited expandability."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:126(para)
msgid "2U rack-mounted servers offer the expanded storage and networking capacity that 1U servers tend to lack, but with a corresponding decrease in server density (half the density offered by 1U rack-mounted servers)."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:133(para)
msgid "Larger rack-mounted servers, such as 4U servers, will tend to offer even greater CPU capacity, often supporting four or even eight CPU sockets. These servers often have much greater expandability so will provide the best option for upgradability. This means, however, that the servers have a much lower server density and a much greater hardware cost."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:142(para)
msgid "<emphasis>Sled servers</emphasis> are rack-mounted servers that support multiple independent servers in a single 2U or 3U enclosure. This form factor offers increased density over typical 1U-2U rack-mounted servers but tends to suffer from limitations in the amount of storage or network capacity each individual server supports."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:151(para)
msgid "The best form factor for server hardware supporting a general purpose OpenStack cloud is driven by outside business and cost factors. No single reference architecture applies to all implementations; the decision must flow from user requirements, technical considerations, and operational considerations. Here are some of the key factors that influence the selection of server hardware:"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:163(para)
msgid "Sizing is an important consideration for a general purpose OpenStack cloud. The expected or anticipated number of instances that each hypervisor can host is a common meter used in sizing the deployment. The selected server hardware needs to support the expected or anticipated instance density."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:175(para)
msgid "Physical data centers have limited physical space, power, and cooling. The number of hosts (or hypervisors) that can be fitted into a given metric (rack, rack unit, or floor tile) is another important method of sizing. Floor weight is an often overlooked consideration. The data center floor must be able to support the weight of the proposed number of hosts within a rack or set of racks. These factors need to be applied as part of the host density calculation and server hardware selection."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:188(term)
msgid "Power density"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:190(para)
msgid "Data centers have a specified amount of power fed to a given rack or set of racks. Older data centers may have a power density as power as low as 20 AMPs per rack, while more recent data centers can be architected to support power densities as high as 120 AMP per rack. The selected server hardware must take power density into account."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:200(term)
msgid "Network connectivity"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:202(para)
msgid "The selected server hardware must have the appropriate number of network connections, as well as the right type of network connections, in order to support the proposed architecture. Ensure that, at a minimum, there are at least two diverse network connections coming into each rack."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:212(para)
msgid "The selection of form factors or architectures affects the selection of server hardware. Ensure that the selected server hardware is configured to support enough storage capacity (or storage expandability) to match the requirements of selected scale-out storage solution. Similarly, the network architecture impacts the server hardware selection and vice versa."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:220(title)
msgid "Selecting storage hardware"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:221(para)
msgid "Determine storage hardware architecture by selecting specific storage architecture. Determine the selection of storage architecture by evaluating possible solutions against the critical factors, the user requirements, technical considerations, and operational considerations. Incorporate the following facts into your storage architecture:"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:231(para)
msgid "Storage can be a significant portion of the overall system cost. For an organization that is concerned with vendor support, a commercial storage solution is advisable, although it comes with a higher price tag. If initial capital expenditure requires minimization, designing a system based on commodity hardware would apply. The trade-off is potentially higher support costs and a greater risk of incompatibility and interoperability issues."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:245(para)
msgid "Scalability, along with expandability, is a major consideration in a general purpose OpenStack cloud. It might be difficult to predict the final intended size of the implementation as there are no established usage patterns for a general purpose cloud. It might become necessary to expand the initial deployment in order to accommodate growth and user demand."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:257(para)
msgid "Expandability is a major architecture factor for storage solutions with general purpose OpenStack cloud. A storage solution that expands to 50PB is considered more expandable than a solution that only scales to 10PB. This meter is related to scalability, which is the measure of a solution's performance as it expands."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:267(para)
msgid "Using a scale-out storage solution with direct-attached storage (DAS) in the servers is well suited for a general purpose OpenStack cloud. Cloud services requirements determine your choice of scale-out solution. You need to determine if a single, highly expandable and highly vertical, scalable, centralized storage array is suitable for your design. After determining an approach, select the storage hardware based on this criteria."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:275(para)
msgid "This list expands upon the potential impacts for including a particular storage architecture (and corresponding storage hardware) into the design for a general purpose OpenStack cloud:"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:283(para)
msgid "Ensure that, if storage protocols other than Ethernet are part of the storage solution, the appropriate hardware has been selected. If a centralized storage array is selected, ensure that the hypervisor will be able to connect to that storage array for image storage."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:292(term)
msgid "Usage"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:294(para)
msgid "How the particular storage architecture will be used is critical for determining the architecture. Some of the configurations that will influence the architecture include whether it will be used by the hypervisors for ephemeral instance storage or if OpenStack Object Storage will use it for object storage."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:303(term)
msgid "Instance and image locations"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:305(para)
msgid "Where instances and images will be stored will influence the architecture."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:313(para)
msgid "If the solution is a scale-out storage architecture that includes DAS, it will affect the server hardware selection. This could ripple into the decisions that affect host density, instance density, power density, OS-hypervisor, management tools and others."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:322(para)
msgid "General purpose OpenStack cloud has multiple options. The key factors that will have an influence on selection of storage hardware for a general purpose OpenStack cloud are as follows:"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:328(term)
msgid "Capacity"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:330(para)
msgid "Hardware resources selected for the resource nodes should be capable of supporting enough storage for the cloud services. Defining the initial requirements and ensuring the design can support adding capacity is important. Hardware nodes selected for object storage should be capable of support a large number of inexpensive disks with no reliance on RAID controller cards. Hardware nodes selected for block storage should be capable of supporting high speed storage solutions and RAID controller cards to provide performance and redundancy to storage at a hardware level. Selecting hardware RAID controllers that automatically repair damaged arrays will assist with the replacement and repair of degraded or deleted storage devices."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:349(para)
msgid "Disks selected for object storage services do not need to be fast performing disks. We recommend that object storage nodes take advantage of the best cost per terabyte available for storage. Contrastingly, disks chosen for block storage services should take advantage of performance boosting features that may entail the use of SSDs or flash storage to provide high performance block storage pools. Storage performance of ephemeral disks used for instances should also be taken into consideration."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:361(term)
msgid "Fault tolerance"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:363(para)
msgid "Object storage resource nodes have no requirements for hardware fault tolerance or RAID controllers. It is not necessary to plan for fault tolerance within the object storage hardware because the object storage service provides replication between zones as a feature of the service. Block storage nodes, compute nodes, and cloud controllers should all have fault tolerance built in at the hardware level by making use of hardware RAID controllers and varying levels of RAID configuration. The level of RAID chosen should be consistent with the performance and availability requirements of the cloud."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:383(para)
msgid "Selecting network architecture determines which network hardware will be used. Networking software is determined by the selected networking hardware."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:386(para)
msgid "There are more subtle design impacts that need to be considered. The selection of certain networking hardware (and the networking software) affects the management tools that can be used. There are exceptions to this; the rise of <emphasis>open</emphasis> networking software that supports a range of networking hardware means that there are instances where the relationship between networking hardware and networking software are not as tightly defined."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:393(para)
msgid "Some of the key considerations that should be included in the selection of networking hardware include:"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:399(para)
msgid "The design will require networking hardware that has the requisite port count."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:406(para)
msgid "The network design will be affected by the physical space that is required to provide the requisite port count. A higher port density is preferred, as it leaves more rack space for compute or storage components that may be required by the design. This can also lead into concerns about fault domains and power density that should be considered. Higher density switches are more expensive and should also be considered, as it is important not to over design the network if it is not required."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:430(para)
msgid "The level of network hardware redundancy required is influenced by the user requirements for high availability and cost considerations. Network redundancy can be achieved by adding redundant power supplies or paired switches. If this is a requirement, the hardware will need to support this configuration."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:441(para)
msgid "Ensure that the physical data center provides the necessary power for the selected network hardware."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:445(para)
msgid "This may be an issue for spine switches in a leaf and spine fabric, or end of row (EoR) switches."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:452(para)
msgid "There is no single best practice architecture for the networking hardware supporting a general purpose OpenStack cloud that will apply to all implementations. Some of the key factors that will have a strong influence on selection of networking hardware include:"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:461(para)
msgid "All nodes within an OpenStack cloud require network connectivity. In some cases, nodes require access to more than one network segment. The design must encompass sufficient network capacity and bandwidth to ensure that all communications within the cloud, both north-south and east-west traffic have sufficient resources available."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:474(para)
msgid "The network design should encompass a physical and logical network design that can be easily expanded upon. Network hardware should offer the appropriate types of interfaces and speeds that are required by the hardware nodes."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:482(term) ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:575(title)
msgid "Availability"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:484(para)
msgid "To ensure that access to nodes within the cloud is not interrupted, we recommend that the network architecture identify any single points of failure and provide some level of redundancy or fault tolerance. With regard to the network infrastructure itself, this often involves use of networking protocols such as LACP, VRRP or others to achieve a highly available network connection. In addition, it is important to consider the networking implications on API availability. In order to ensure that the APIs, and potentially other services in the cloud are highly available, we recommend you design a load balancing solution within the network architecture to accommodate for these requirements."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:505(para)
msgid "Software selection for a general purpose OpenStack architecture design needs to include these three areas:"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:522(para)
msgid "The operating system (OS) and hypervisor have a significant impact on the overall design. Selecting a particular operating system and hypervisor can directly affect server hardware selection. Make sure the storage hardware and topology support the selected operating system and hypervisor combination. Also ensure the networking hardware selection and topology will work with the chosen operating system and hypervisor combination."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:530(para)
msgid "Some areas that could be impacted by the selection of OS and hypervisor include:"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:536(para)
msgid "Selecting a commercially supported hypervisor, such as Microsoft Hyper-V, will result in a different cost model rather than community-supported open source hypervisors including <glossterm baseform=\"kernel-based VM (KVM)\">KVM</glossterm>, Kinstance or <glossterm>Xen</glossterm>. When comparing open source OS solutions, choosing Ubuntu over Red Hat (or vice versa) will have an impact on cost due to support contracts."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:550(para)
msgid "Depending on the selected hypervisor, staff should have the appropriate training and knowledge to support the selected OS and hypervisor combination. If they do not, training will need to be provided which could have a cost impact on the design."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:561(para)
msgid "The management tools used for Ubuntu and Kinstance differ from the management tools for VMware vSphere. Although both OS and hypervisor combinations are supported by OpenStack, there will be very different impacts to the rest of the design as a result of the selection of one combination versus the other."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:573(para)
msgid "Ensure that selected OS and hypervisor combinations meet the appropriate scale and performance requirements. The chosen architecture will need to meet the targeted instance-host ratios with the selected OS-hypervisor combinations."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:583(para)
msgid "Ensure that the design can accommodate regular periodic installations of application security patches while maintaining required workloads. The frequency of security patches for the proposed OS-hypervisor combination will have an impact on performance and the patch installation process could affect maintenance windows."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:595(para)
msgid "Determine which features of OpenStack are required. This will often determine the selection of the OS-hypervisor combination. Some features are only available with specific operating systems or hypervisors."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:604(para)
msgid "You will need to consider how the OS and hypervisor combination interactions with other operating systems and hypervisors, including other software solutions. Operational troubleshooting tools for one OS-hypervisor combination may differ from the tools used for another OS-hypervisor combination and, as a result, the design will need to address if the two sets of tools need to interoperate."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:618(para)
msgid "Selecting which OpenStack components are included in the overall design is important. Some OpenStack components, like compute and Image service, are required in every architecture. Other components, like Orchestration, are not always required."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:622(para)
msgid "Excluding certain OpenStack components can limit or constrain the functionality of other components. For example, if the architecture includes Orchestration but excludes Telemetry, then the design will not be able to take advantage of Orchestrations' auto scaling functionality. It is important to research the component interdependencies in conjunction with the technical requirements before deciding on the final architecture."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:632(para)
msgid "OpenStack Networking (neutron) provides a wide variety of networking services for instances. There are many additional networking software packages that can be useful when managing OpenStack components. Some examples include:"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:638(para)
msgid "Software to provide load balancing"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:643(para)
msgid "Network redundancy protocols"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:648(para)
msgid "Routing daemons"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:653(para)
msgid "Some of these software packages are described in more detail in the <citetitle>OpenStack High Availability Guide</citetitle> (refer to the <link xlink:href=\"http://docs.openstack.org/ha-guide/networking-ha.html\">Network controller cluster stack chapter</link> of the OpenStack High Availability Guide)."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:659(para)
msgid "For a general purpose OpenStack cloud, the OpenStack infrastructure components need to be highly available. If the design does not include hardware load balancing, networking software packages like HAProxy will need to be included."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:668(para)
msgid "Selected supplemental software solution impacts and affects the overall OpenStack cloud design. This includes software for providing clustering, logging, monitoring and alerting."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:672(para)
msgid "Inclusion of clustering software, such as Corosync or Pacemaker, is determined primarily by the availability requirements. The impact of including (or not including) these software packages is primarily determined by the availability of the cloud infrastructure and the complexity of supporting the configuration after it is deployed. The <link xlink:href=\"http://docs.openstack.org/ha-guide/\"><citetitle>OpenStack High Availability Guide</citetitle></link> provides more details on the installation and configuration of Corosync and Pacemaker, should these packages need to be included in the design."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:683(para)
msgid "Requirements for logging, monitoring, and alerting are determined by operational considerations. Each of these sub-categories includes a number of various options."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:686(para)
msgid "If these software packages are required, the design must account for the additional resource consumption (CPU, RAM, storage, and network bandwidth). Some other potential design impacts include:"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:692(para)
msgid "OS-hypervisor combination: Ensure that the selected logging, monitoring, or alerting tools support the proposed OS-hypervisor combination."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_architecture_general_purpose.xml:706(para)
msgid "OpenStack components often require access to back-end database services to store state and configuration information. Selecting an appropriate back-end database that satisfies the availability and fault tolerance requirements of the OpenStack services is required. OpenStack services supports connecting to a database that is supported by the SQLAlchemy python drivers, however, most common database deployments make use of MySQL or variations of it. We recommend that the database, which provides back-end service within a general purpose cloud, be made highly available when using an available technology which can accomplish that goal."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_operational_considerations_general_purpose.xml:9(para)
msgid "In the planning and design phases of the build out, it is important to include the operation's function. Operational factors affect the design choices for a general purpose cloud, and operations staff are often tasked with the maintenance of cloud environments for larger installations."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_operational_considerations_general_purpose.xml:14(para)
msgid "Expectations set by the Service Level Agreements (SLAs) directly affect knowing when and where you should implement redundancy and high availability. SLAs are contractual obligations that provide assurances for service availability. They define the levels of availability that drive the technical design, often with penalties for not meeting contractual obligations."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_operational_considerations_general_purpose.xml:20(para)
msgid "SLA terms that affect design include:"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_operational_considerations_general_purpose.xml:23(para)
msgid "API availability guarantees implying multiple infrastructure services and highly available load balancers."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_operational_considerations_general_purpose.xml:28(para)
msgid "Network uptime guarantees affecting switch design, which might require redundant switching and power."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_operational_considerations_general_purpose.xml:33(para)
msgid "Factor in networking security policy requirements in to your deployments."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_operational_considerations_general_purpose.xml:39(title)
msgid "Support and maintainability"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_operational_considerations_general_purpose.xml:40(para)
msgid "To be able to support and maintain an installation, OpenStack cloud management requires operations staff to understand and comprehend design architecture content. The operations and engineering staff skill level, and level of separation, are dependent on size and purpose of the installation. Large cloud service providers, or telecom providers, are more likely to be managed by specially trained, dedicated operations organizations. Smaller implementations are more likely to rely on support staff that need to take on combined engineering, design and operations functions."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_operational_considerations_general_purpose.xml:49(para)
msgid "Maintaining OpenStack installations requires a variety of technical skills. You may want to consider using a third-party management company with special expertise in managing OpenStack deployment."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_operational_considerations_general_purpose.xml:57(para)
msgid "OpenStack clouds require appropriate monitoring platforms to ensure errors are caught and managed appropriately. Specific meters that are critically important to monitor include:"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_operational_considerations_general_purpose.xml:72(para)
msgid "Leveraging existing monitoring systems is an effective check to ensure OpenStack environments can be monitored."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_operational_considerations_general_purpose.xml:77(title)
msgid "Downtime"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_operational_considerations_general_purpose.xml:78(para)
msgid "To effectively run cloud installations, initial downtime planning includes creating processes and architectures that support the following:"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_operational_considerations_general_purpose.xml:83(para)
msgid "Planned (maintenance)"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_operational_considerations_general_purpose.xml:88(para)
msgid "Unplanned (system faults)"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_operational_considerations_general_purpose.xml:93(para)
msgid "Resiliency of overall system and individual components are going to be dictated by the requirements of the SLA, meaning designing for high availability (HA) can have cost ramifications."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_operational_considerations_general_purpose.xml:100(para)
msgid "Capacity constraints for a general purpose cloud environment include:"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_operational_considerations_general_purpose.xml:104(para)
msgid "Compute limits"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_operational_considerations_general_purpose.xml:109(para)
msgid "Storage limits"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_operational_considerations_general_purpose.xml:114(para)
msgid "A relationship exists between the size of the compute environment and the supporting OpenStack infrastructure controller nodes requiring support."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_operational_considerations_general_purpose.xml:117(para)
msgid "Increasing the size of the supporting compute environment increases the network traffic and messages, adding load to the controller or networking nodes. Effective monitoring of the environment will help with capacity decisions on scaling."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_operational_considerations_general_purpose.xml:121(para)
msgid "Compute nodes automatically attach to OpenStack clouds, resulting in a horizontally scaling process when adding extra compute capacity to an OpenStack cloud. Additional processes are required to place nodes into appropriate availability zones and host aggregates. When adding additional compute nodes to environments, ensure identical or functional compatible CPUs are used, otherwise live migration features will break. It is necessary to add rack capacity or network switches as scaling out compute hosts directly affects network and datacenter resources."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_operational_considerations_general_purpose.xml:129(para)
msgid "Assessing the average workloads and increasing the number of instances that can run within the compute environment by adjusting the overcommit ratio is another option. It is important to remember that changing the CPU overcommit ratio can have a detrimental effect and cause a potential increase in a noisy neighbor. The additional risk of increasing the overcommit ratio is more instances failing when a compute host fails."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_operational_considerations_general_purpose.xml:135(para)
msgid "Compute host components can also be upgraded to account for increases in demand; this is known as vertical scaling. Upgrading CPUs with more cores, or increasing the overall server memory, can add extra needed capacity depending on whether the running applications are more CPU intensive or memory intensive."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_operational_considerations_general_purpose.xml:141(para)
msgid "Insufficient disk capacity could also have a negative effect on overall performance including CPU and memory usage. Depending on the back-end architecture of the OpenStack Block Storage layer, capacity includes adding disk shelves to enterprise storage systems or installing additional block storage nodes. Upgrading directly attached storage installed in compute hosts, and adding capacity to the shared storage for additional ephemeral storage to instances, may be necessary."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_operational_considerations_general_purpose.xml:149(para)
msgid "For a deeper discussion on many of these topics, refer to the <link xlink:href=\"http://docs.openstack.org/ops\"><citetitle>OpenStack Operations Guide</citetitle></link>."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:13(para)
msgid "General purpose clouds are expected to include these base services:"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:32(para)
msgid "Each of these services have different resource requirements. As a result, you must make design decisions relating directly to the service, as well as provide a balanced infrastructure for all services."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:36(para)
msgid "Take into consideration the unique aspects of each service, as individual characteristics and service mass can impact the hardware selection process. Hardware designs should be generated for each of the services."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:40(para)
msgid "Hardware decisions are also made in relation to network architecture and facilities planning. These factors play heavily into the overall architecture of an OpenStack cloud."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:45(title)
msgid "Compute resource design"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:46(para)
msgid "When designing compute resource pools, a number of factors can impact your design decisions. Factors such as number of processors, amount of memory, and the quantity of storage required for each hypervisor must be taken into account."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:50(para)
msgid "You will also need to decide whether to provide compute resources in a single pool or in multiple pools. In most cases, multiple pools of resources can be allocated and addressed on demand. A compute design that allocates multiple pools of resources makes best use of application resources, and is commonly referred to as <firstterm>bin packing</firstterm>."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:56(para)
msgid "In a bin packing design, each independent resource pool provides service for specific flavors. This helps to ensure that, as instances are scheduled onto compute hypervisors, each independent node's resources will be allocated in a way that makes the most efficient use of the available hardware. Bin packing also requires a common hardware design, with all hardware nodes within a compute resource pool sharing a common processor, memory, and storage layout. This makes it easier to deploy, support, and maintain nodes throughout their life cycle."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:64(para)
msgid "An <firstterm>overcommit ratio</firstterm> is the ratio of available virtual resources to available physical resources. This ratio is configurable for CPU and memory. The default CPU overcommit ratio is 16:1, and the default memory overcommit ratio is 1.5:1. Determining the tuning of the overcommit ratios during the design phase is important as it has a direct impact on the hardware layout of your compute nodes."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:70(para)
msgid "When selecting a processor, compare features and performance characteristics. Some processors include features specific to virtualized compute hosts, such as hardware-assisted virtualization, and technology related to memory paging (also known as EPT shadowing). These types of features can have a significant impact on the performance of your virtual machine."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:75(para)
msgid "You will also need to consider the compute requirements of non-hypervisor nodes (sometimes referred to as resource nodes). This includes controller, object storage, and block storage nodes, and networking services."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:78(para)
msgid "The number of processor cores and threads impacts the number of worker threads which can be run on a resource node. Design decisions must relate directly to the service being run on it, as well as provide a balanced infrastructure for all services."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:82(para)
msgid "Workload can be unpredictable in a general purpose cloud, so consider including the ability to add additional compute resource pools on demand. In some cases, however, the demand for certain instance types or flavors may not justify individual hardware design. In either case, start by allocating hardware designs that are capable of servicing the most common instance requests. If you want to add additional hardware to the overall architecture, this can be done later."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:92(title)
msgid "Designing network resources"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:93(para)
msgid "OpenStack clouds generally have multiple network segments, with each segment providing access to particular resources. The network services themselves also require network communication paths which should be separated from the other networks. When designing network services for a general purpose cloud, plan for either a physical or logical separation of network segments used by operators and tenants. You can also create an additional network segment for access to internal services such as the message bus and database used by various services. Segregating these services onto separate networks helps to protect sensitive data and protects against unauthorized access to services."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:103(para)
msgid "Choose a networking service based on the requirements of your instances. The architecture and design of your cloud will impact whether you choose OpenStack Networking(neutron), or legacy networking (nova-network)."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:110(para)
msgid "The legacy networking (nova-network) service is primarily a layer-2 networking service that functions in two modes, which use VLANs in different ways. In a flat network mode, all network hardware nodes and devices throughout the cloud are connected to a single layer-2 network segment that provides access to application data."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:116(para)
msgid "When the network devices in the cloud support segmentation using VLANs, legacy networking can operate in the second mode. In this design model, each tenant within the cloud is assigned a network subnet which is mapped to a VLAN on the physical network. It is especially important to remember the maximum number of 4096 VLANs which can be used within a spanning tree domain. This places a hard limit on the amount of growth possible within the data center. When designing a general purpose cloud intended to support multiple tenants, we recommend the use of legacy networking with VLANs, and not in flat network mode."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:130(para)
msgid "Another consideration regarding network is the fact that legacy networking is entirely managed by the cloud operator; tenants do not have control over network resources. If tenants require the ability to manage and create network resources such as network segments and subnets, it will be necessary to install the OpenStack Networking service to provide network access to instances."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:139(term)
msgid "OpenStack Networking (neutron)"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:141(para)
msgid "OpenStack Networking (neutron) is a first class networking service that gives full control over creation of virtual network resources to tenants. This is often accomplished in the form of tunneling protocols which will establish encapsulated communication paths over existing network infrastructure in order to segment tenant traffic. These methods vary depending on the specific implementation, but some of the more common methods include tunneling over GRE, encapsulating with VXLAN, and VLAN tags."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:153(para)
msgid "We recommend you design at least three network segments:"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:156(para)
msgid "The first segment is a public network, used for access to REST APIs by tenants and operators. The controller nodes and swift proxies are the only devices connecting to this network segment. In some cases, this network might also be serviced by hardware load balancers and other network devices."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:163(para)
msgid "The second segment is used by administrators to manage hardware resources. Configuration management tools also use this for deploying software and services onto new hardware. In some cases, this network segment might also be used for internal services, including the message bus and database services. This network needs to communicate with every hardware node. Due to the highly sensitive nature of this network segment, you also need to secure this network from unauthorized access."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:172(para)
msgid "The third network segment is used by applications and consumers to access the physical network, and for users to access applications. This network is segregated from the one used to access the cloud APIs and is not capable of communicating directly with the hardware resources in the cloud. Compute resource nodes and network gateway services which allow application data to access the physical network from outside of the cloud need to communicate on this network segment."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:184(title)
msgid "Designing OpenStack Object Storage"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:185(para)
msgid "When designing hardware resources for OpenStack Object Storage, the primary goal is to maximize the amount of storage in each resource node while also ensuring that the cost per terabyte is kept to a minimum. This often involves utilizing servers which can hold a large number of spinning disks. Whether choosing to use 2U server form factors with directly attached storage or an external chassis that holds a larger number of drives, the main goal is to maximize the storage available in each node."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:195(para)
msgid "We do not recommended investing in enterprise class drives for an OpenStack Object Storage cluster. The consistency and partition tolerance characteristics of OpenStack Object Storage ensures that data stays up to date and survives hardware faults without the use of any specialized data replication devices."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:202(para)
msgid "One of the benefits of OpenStack Object Storage is the ability to mix and match drives by making use of weighting within the swift ring. When designing your swift storage cluster, we recommend making use of the most cost effective storage solution available at the time."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:207(para)
msgid "To achieve durability and availability of data stored as objects it is important to design object storage resource pools to ensure they can provide the suggested availability. Considering rack-level and zone-level designs to accommodate the number of replicas configured to be stored in the Object Storage service (the default number of replicas is three) is important when designing beyond the hardware node level. Each replica of data should exist in its own availability zone with its own power, cooling, and network resources available to service that specific zone."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:216(para)
msgid "Object storage nodes should be designed so that the number of requests does not hinder the performance of the cluster. The object storage service is a chatty protocol, therefore making use of multiple processors that have higher core counts will ensure the IO requests do not inundate the server."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:224(title)
msgid "Designing OpenStack Block Storage"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:225(para)
msgid "When designing OpenStack Block Storage resource nodes, it is helpful to understand the workloads and requirements that will drive the use of block storage in the cloud. We recommend designing block storage pools so that tenants can choose appropriate storage solutions for their applications. By creating multiple storage pools of different types, in conjunction with configuring an advanced storage scheduler for the block storage service, it is possible to provide tenants with a large catalog of storage services with a variety of performance levels and redundancy options."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:234(para)
msgid "Block storage also takes advantage of a number of enterprise storage solutions. These are addressed via a plug-in driver developed by the hardware vendor. A large number of enterprise storage plug-in drivers ship out-of-the-box with OpenStack Block Storage (and many more available via third party channels). General purpose clouds are more likely to use directly attached storage in the majority of block storage nodes, deeming it necessary to provide additional levels of service to tenants which can only be provided by enterprise class storage solutions."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:243(para)
msgid "Redundancy and availability requirements impact the decision to use a RAID controller card in block storage nodes. The input-output per second (IOPS) demand of your application will influence whether or not you should use a RAID controller, and which level of RAID is required. Making use of higher performing RAID volumes is suggested when considering performance. However, where redundancy of block storage volumes is more important we recommend making use of a redundant RAID configuration such as RAID 5 or RAID 6. Some specialized features, such as automated replication of block storage volumes, may require the use of third-party plug-ins and enterprise block storage solutions in order to provide the high demand on storage. Furthermore, where extreme performance is a requirement it may also be necessary to make use of high speed SSD disk drives' high performing flash storage solutions."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:262(para)
msgid "The software selection process plays a large role in the architecture of a general purpose cloud. The following have a large impact on the design of the cloud:"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:267(para)
msgid "Choice of operating system"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:272(para)
msgid "Selection of OpenStack software components"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:277(para)
msgid "Choice of hypervisor"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:282(para)
msgid "Selection of supplemental software"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:287(para)
msgid "Operating system (OS) selection plays a large role in the design and architecture of a cloud. There are a number of OSes which have native support for OpenStack including:"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:292(para)
msgid "Ubuntu"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:297(para)
msgid "Red Hat Enterprise Linux (RHEL)"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:302(para)
msgid "CentOS"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:307(para)
msgid "SUSE Linux Enterprise Server (SLES)"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:313(para)
msgid "Native support is not a constraint on the choice of OS; users are free to choose just about any Linux distribution (or even Microsoft Windows) and install OpenStack directly from source (or compile their own packages). However, many organizations will prefer to install OpenStack from distribution-supplied packages or repositories (although using the distribution vendor's OpenStack packages might be a requirement for support)."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:322(para)
msgid "OS selection also directly influences hypervisor selection. A cloud architect who selects Ubuntu, RHEL, or SLES has some flexibility in hypervisor; KVM, Xen, and LXC are supported virtualization methods available under OpenStack Compute (nova) on these Linux distributions. However, a cloud architect who selects Hyper-V is limited to Windows Servers. Similarly, a cloud architect who selects XenServer is limited to the CentOS-based dom0 operating system provided with XenServer."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:330(para)
msgid "The primary factors that play into OS-hypervisor selection include:"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:336(para)
msgid "The selection of OS-hypervisor combination first and foremost needs to support the user requirements."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:342(term)
msgid "Support"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:344(para)
msgid "The selected OS-hypervisor combination needs to be supported by OpenStack."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:351(para)
msgid "The OS-hypervisor needs to be interoperable with other features and services in the OpenStack design in order to meet the user requirements."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:362(para)
msgid "OpenStack supports a wide variety of hypervisors, one or more of which can be used in a single cloud. These hypervisors include:"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:367(para)
msgid "KVM (and QEMU)"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:370(para)
msgid "XCP/XenServer"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:373(para)
msgid "vSphere (vCenter and ESXi)"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:376(para)
msgid "Hyper-V"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:379(para)
msgid "LXC"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:382(para)
msgid "Docker"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:385(para)
msgid "Bare-metal"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:388(para)
msgid "A complete list of supported hypervisors and their capabilities can be found at <link xlink:href=\"https://wiki.openstack.org/wiki/HypervisorSupportMatrix\">OpenStack Hypervisor Support Matrix</link>."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:392(para)
msgid "We recommend general purpose clouds use hypervisors that support the most general purpose use cases, such as KVM and Xen. More specific hypervisors should be chosen to account for specific functionality or a supported feature requirement. In some cases, there may also be a mandated requirement to run software on a certified hypervisor including solutions from VMware, Microsoft, and Citrix."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:399(para)
msgid "The features offered through the OpenStack cloud platform determine the best choice of a hypervisor. Each hypervisor has their own hardware requirements which may affect the decisions around designing a general purpose cloud."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:403(para)
msgid "In a mixed hypervisor environment, specific aggregates of compute resources, each with defined capabilities, enable workloads to utilize software and hardware specific to their particular requirements. This functionality can be exposed explicitly to the end user, or accessed through defined metadata within a particular flavor of an instance."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:413(para)
msgid "A general purpose OpenStack cloud design should incorporate the core OpenStack services to provide a wide range of services to end-users. The OpenStack core services recommended in a general purpose cloud are:"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:419(para)
msgid "OpenStack <glossterm>Compute</glossterm> (<glossterm>nova</glossterm>)"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:423(para)
msgid "OpenStack <glossterm>Networking</glossterm> (<glossterm>neutron</glossterm>)"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:427(para)
msgid "OpenStack <glossterm>Image service</glossterm> (<glossterm>glance</glossterm>)"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:431(para)
msgid "OpenStack <glossterm>Identity</glossterm> (<glossterm>keystone</glossterm>)"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:435(para)
msgid "OpenStack <glossterm>dashboard</glossterm> (<glossterm>horizon</glossterm>)"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:439(para)
msgid "<glossterm>Telemetry</glossterm> (<glossterm>ceilometer</glossterm>)"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:443(para)
msgid "A general purpose cloud may also include OpenStack <glossterm>Object Storage</glossterm> (<glossterm>swift</glossterm>). OpenStack <glossterm>Block Storage</glossterm> (<glossterm>cinder</glossterm>). These may be selected to provide storage to applications and instances."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:453(para)
msgid "A general purpose OpenStack deployment consists of more than just OpenStack-specific components. A typical deployment involves services that provide supporting functionality, including databases and message queues, and may also involve software to provide high availability of the OpenStack environment. Design decisions around the underlying message queue might affect the required number of controller services, as well as the technology to provide highly resilient database functionality, such as MariaDB with Galera. In such a scenario, replication of services relies on quorum."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:463(para)
msgid "Where many general purpose deployments use hardware load balancers to provide highly available API access and SSL termination, software solutions, for example HAProxy, can also be considered. It is vital to ensure that such software implementations are also made highly available. High availability can be achieved by using software such as Keepalived or Pacemaker with Corosync. Pacemaker and Corosync can provide active-active or active-passive highly available configuration depending on the specific service in the OpenStack environment. Using this software can affect the design as it assumes at least a 2-node controller infrastructure where one of those nodes may be running certain services in standby mode."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:476(para)
msgid "Memcached is a distributed memory object caching system, and Redis is a key-value store. Both are deployed on general purpose clouds to assist in alleviating load to the Identity service. The memcached service caches tokens, and due to its distributed nature it can help alleviate some bottlenecks to the underlying authentication system. Using memcached or Redis does not affect the overall design of your architecture as they tend to be deployed onto the infrastructure nodes providing the OpenStack services."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:488(title)
msgid "Controller infrastructure"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:489(para)
msgid "The Controller infrastructure nodes provide management services to the end-user as well as providing services internally for the operating of the cloud. The Controllers run message queuing services that carry system messages between each service. Performance issues related to the message bus would lead to delays in sending that message to where it needs to go. The result of this condition would be delays in operation functions such as spinning up and deleting instances, provisioning new storage volumes and managing network resources. Such delays could adversely affect an application’s ability to react to certain conditions, especially when using auto-scaling features. It is important to properly design the hardware used to run the controller infrastructure as outlined above in the Hardware Selection section."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:504(para)
msgid "Performance of the controller services is not limited to processing power, but restrictions may emerge in serving concurrent users. Ensure that the APIs and Horizon services are load tested to ensure that you are able to serve your customers. Particular attention should be made to the OpenStack Identity Service (Keystone), which provides the authentication and authorization for all services, both internally to OpenStack itself and to end-users. This service can lead to a degradation of overall performance if this is not sized appropriately."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:517(title)
msgid "Network performance"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:518(para)
msgid "In a general purpose OpenStack cloud, the requirements of the network help determine performance capabilities. It is possible to design OpenStack environments that run a mix of networking capabilities. By utilizing the different interface speeds, the users of the OpenStack environment can choose networks that are fit for their purpose."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:525(para)
msgid "Network performance can be boosted considerably by implementing hardware load balancers to provide front-end service to the cloud APIs. The hardware load balancers also perform SSL termination if that is a requirement of your environment. When implementing SSL offloading, it is important to understand the SSL offloading capabilities of the devices selected."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:535(title)
msgid "Compute host"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:536(para)
msgid "The choice of hardware specifications used in compute nodes including CPU, memory and disk type directly affects the performance of the instances. Other factors which can directly affect performance include tunable parameters within the OpenStack services, for example the overcommit ratio applied to resources. The defaults in OpenStack Compute set a 16:1 over-commit of the CPU and 1.5 over-commit of the memory. Running at such high ratios leads to an increase in \"noisy-neighbor\" activity. Care must be taken when sizing your Compute environment to avoid this scenario. For running general purpose OpenStack environments it is possible to keep to the defaults, but make sure to monitor your environment as usage increases."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:552(title)
msgid "Storage performance"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:553(para)
msgid "When considering performance of OpenStack Block Storage, hardware and architecture choice is important. Block Storage can use enterprise back-end systems such as NetApp or EMC, scale out storage such as GlusterFS and Ceph, or simply use the capabilities of directly attached storage in the nodes themselves. Block Storage may be deployed so that traffic traverses the host network, which could affect, and be adversely affected by, the front-side API traffic performance. As such, consider using a dedicated data storage network with dedicated interfaces on the Controller and Compute hosts."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:564(para)
msgid "When considering performance of OpenStack Object Storage, a number of design choices will affect performance. A user’s access to the Object Storage is through the proxy services, which sit behind hardware load balancers. By the very nature of a highly resilient storage system, replication of the data would affect performance of the overall system. In this case, 10 GbE (or better) networking is recommended throughout the storage network architecture."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:576(para)
msgid "In OpenStack, the infrastructure is integral to providing services and should always be available, especially when operating with SLAs. Ensuring network availability is accomplished by designing the network architecture so that no single point of failure exists. A consideration of the number of switches, routes and redundancies of power should be factored into core infrastructure, as well as the associated bonding of networks to provide diverse routes to your highly available switch infrastructure."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:585(para)
msgid "The OpenStack services themselves should be deployed across multiple servers that do not represent a single point of failure. Ensuring API availability can be achieved by placing these services behind highly available load balancers that have multiple OpenStack servers as members."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:590(para)
msgid "OpenStack lends itself to deployment in a highly available manner where it is expected that at least 2 servers be utilized. These can run all the services involved from the message queuing service, for example RabbitMQ or QPID, and an appropriately deployed database service such as MySQL or MariaDB. As services in the cloud are scaled out, back-end services will need to scale too. Monitoring and reporting on server utilization and response times, as well as load testing your systems, will help determine scale out decisions."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:599(para)
msgid "Care must be taken when deciding network functionality. Currently, OpenStack supports both the legacy networking (nova-network) system and the newer, extensible OpenStack Networking (neutron). Both have their pros and cons when it comes to providing highly available access. Legacy networking, which provides networking access maintained in the OpenStack Compute code, provides a feature that removes a single point of failure when it comes to routing, and this feature is currently missing in OpenStack Networking. The effect of legacy networking’s multi-host functionality restricts failure domains to the host running that instance."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:610(para)
msgid "When using OpenStack Networking, the OpenStack controller servers or separate Networking hosts handle routing. For a deployment that requires features available in only Networking, it is possible to remove this restriction by using third party software that helps maintain highly available L3 routes. Doing so allows for common APIs to control network hardware, or to provide complex multi-tier web applications in a secure manner. It is also possible to completely remove routing from Networking, and instead rely on hardware routing capabilities. In this case, the switching infrastructure must support L3 routing."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:622(para)
msgid "OpenStack Networking and legacy networking both have their advantages and disadvantages. They are both valid and supported options that fit different network deployment models described in the <citetitle><link xlink:href=\"http://docs.openstack.org/openstack-ops/content/network_design.html#network_deployment_options\">OpenStack Operations Guide</link></citetitle>."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:629(para)
msgid "Ensure your deployment has adequate back-up capabilities."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:630(para)
msgid "Application design must also be factored into the capabilities of the underlying cloud infrastructure. If the compute hosts do not provide a seamless live migration capability, then it must be expected that when a compute host fails, that instance and any data local to that instance will be deleted. However, when providing an expectation to users that instances have a high-level of uptime guarantees, the infrastructure must be deployed in a way that eliminates any single point of failure when a compute host disappears. This may include utilizing shared file systems on enterprise storage or OpenStack Block storage to provide a level of guarantee to match service features."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:642(para)
msgid "For more information on high availability in OpenStack, see the <link xlink:href=\"http://docs.openstack.org/ha-guide/\"><citetitle>OpenStack High Availability Guide</citetitle></link>."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:650(para)
msgid "A security domain comprises users, applications, servers or networks that share common trust requirements and expectations within a system. Typically they have the same authentication and authorization requirements and users."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:654(para)
msgid "These security domains are:"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:657(para)
msgid "Public"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:660(para)
msgid "Guest"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:669(para)
msgid "These security domains can be mapped to an OpenStack deployment individually, or combined. In each case, the cloud operator should be aware of the appropriate security concerns. Security domains should be mapped out against your specific OpenStack deployment topology. The domains and their trust requirements depend upon whether the cloud instance is public, private, or hybrid."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:678(para)
msgid "The public security domain is an entirely untrusted area of the cloud infrastructure. It can refer to the internet as a whole or simply to networks over which you have no authority. This domain should always be considered untrusted."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:684(para)
msgid "The guest security domain handles compute data generated by instances on the cloud but not services that support the operation of the cloud, such as API calls. Public cloud providers and private cloud providers who do not have stringent controls on instance use or who allow unrestricted internet access to instances should consider this domain to be untrusted. Private cloud providers may want to consider this network as internal and therefore trusted only if they have controls in place to assert that they trust instances and all their tenants."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:696(para)
msgid "The management security domain is where services interact. Sometimes referred to as the <emphasis>control plane</emphasis>, the networks in this domain transport confidential data such as configuration parameters, user names, and passwords. In most deployments this domain is considered trusted."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:703(para)
msgid "The data security domain is concerned primarily with information pertaining to the storage services within OpenStack. Much of the data that crosses this network has high integrity and confidentiality requirements and, depending on the type of deployment, may also have strong availability requirements. The trust level of this network is heavily dependent on other deployment decisions."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:712(para)
msgid "When deploying OpenStack in an enterprise as a private cloud it is usually behind the firewall and within the trusted network alongside existing systems. Users of the cloud are employees that are bound by the security requirements set forth by the company. This tends to push most of the security domains towards a more trusted model. However, when deploying OpenStack in a public facing role, no assumptions can be made and the attack vectors significantly increase."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:721(para)
msgid "Consideration must be taken when managing the users of the system for both public and private clouds. The identity service allows for LDAP to be part of the authentication process. Including such systems in an OpenStack deployment may ease user management if integrating into existing systems."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:727(para)
msgid "It is important to understand that user authentication requests include sensitive information including user names, passwords, and authentication tokens. For this reason, placing the API services behind hardware that performs SSL termination is strongly recommended."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_tech_considerations_general_purpose.xml:732(para)
msgid "For more information OpenStack Security, see the <link xlink:href=\"http://docs.openstack.org/security-guide/\"><citetitle>OpenStack Security Guide</citetitle></link>"
msgstr ""

#. When image changes, this message will be marked fuzzy or untranslated for you.
#. It doesn't matter what you translate it to: it's not used at all.
#: ./doc/arch-design/generalpurpose/section_prescriptive_example_general_purpose.xml:59(None)
msgid "@@image: '../figures/General_Architecture3.png'; md5=278d469e1d026634b3682209c454bff1"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_prescriptive_example_general_purpose.xml:8(title)
msgid "Prescriptive example"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_prescriptive_example_general_purpose.xml:9(para)
msgid "An online classified advertising company wants to run web applications consisting of Tomcat, Nginx and MariaDB in a private cloud. To be able to meet policy requirements, the cloud infrastructure will run in their own data center. The company has predictable load requirements, but requires scaling to cope with nightly increases in demand. Their current environment does not have the flexibility to align with their goal of running an open source API environment. The current environment consists of the following:"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_prescriptive_example_general_purpose.xml:18(para)
msgid "Between 120 and 140 installations of Nginx and Tomcat, each with 2 vCPUs and 4 GB of RAM"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_prescriptive_example_general_purpose.xml:22(para)
msgid "A three-node MariaDB and Galera cluster, each with 4 vCPUs and 8 GB RAM"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_prescriptive_example_general_purpose.xml:26(para)
msgid "The company runs hardware load balancers and multiple web applications serving their websites, and orchestrates environments using combinations of scripts and Puppet. The website generates large amounts of log data daily that requires archiving."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_prescriptive_example_general_purpose.xml:38(para)
msgid "OpenStack Controller service running Image, Identity, Networking, combined with support services such as MariaDB and RabbitMQ, configured for high availability on at least three controller nodes."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_prescriptive_example_general_purpose.xml:48(para)
msgid "OpenStack Block Storage for use by compute instances, requiring persistent storage (such as databases for dynamic sites)."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_prescriptive_example_general_purpose.xml:53(para)
msgid "OpenStack Object Storage for serving static objects (such as images)."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_prescriptive_example_general_purpose.xml:60(para)
msgid "Running up to 140 web instances and the small number of MariaDB instances requires 292 vCPUs available, as well as 584 GB RAM. On a typical 1U server using dual-socket hex-core Intel CPUs with Hyperthreading, and assuming 2:1 CPU overcommit ratio, this would require 8 OpenStack Compute nodes."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_prescriptive_example_general_purpose.xml:66(para)
msgid "The web application instances run from local storage on each of the OpenStack Compute nodes. The web application instances are stateless, meaning that any of the instances can fail and the application will continue to function."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_prescriptive_example_general_purpose.xml:70(para)
msgid "MariaDB server instances store their data on shared enterprise storage, such as NetApp or Solidfire devices. If a MariaDB instance fails, storage would be expected to be re-attached to another instance and rejoined to the Galera cluster."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_prescriptive_example_general_purpose.xml:75(para)
msgid "Logs from the web application servers are shipped to OpenStack Object Storage for processing and archiving."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_prescriptive_example_general_purpose.xml:78(para)
msgid "Additional capabilities can be realized by moving static web content to be served from OpenStack Object Storage containers, and backing the OpenStack Image service with OpenStack Object Storage."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_prescriptive_example_general_purpose.xml:83(para)
msgid "Increasing OpenStack Object Storage means network bandwidth needs to be taken into consideration. Running OpenStack Object Storage with network connections offering 10 GbE or better connectivity is advised."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_prescriptive_example_general_purpose.xml:90(para)
msgid "Leveraging Orchestration and Telemetry services is also a potential issue when providing auto-scaling, orchestrated web application environments. Defining the web applications in <glossterm baseform=\"Heat Orchestration Template (HOT)\">Heat Orchestration Templates (HOT)</glossterm> negates the reliance on the current scripted Puppet solution."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_prescriptive_example_general_purpose.xml:95(para)
msgid "OpenStack Networking can be used to control hardware load balancers through the use of plug-ins and the Networking API. This allows users to control hardware load balance pools and instances as members in these pools, but their use in production environments must be carefully weighed against current stability."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_user_requirements_general_purpose.xml:9(para)
msgid "When building a general purpose cloud, you should follow the <glossterm baseform=\"IaaS\">Infrastructure-as-a-Service (IaaS)</glossterm> model; a platform best suited for use cases with simple requirements. General purpose cloud user requirements are not complex. However, it is important to capture them even if the project has minimum business and technical requirements, such as a proof of concept (PoC), or a small lab platform."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_user_requirements_general_purpose.xml:17(para)
msgid "The following user considerations are written from the perspective of the cloud builder, not from the perspective of the end user."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_user_requirements_general_purpose.xml:26(para)
msgid "Financial factors are a primary concern for any organization. Cost is an important criterion as general purpose clouds are considered the baseline from which all other cloud architecture environments derive. General purpose clouds do not always provide the most cost-effective environment for specialized applications or situations. Unless razor-thin margins and costs have been mandated as a critical factor, cost should not be the sole consideration when choosing or designing a general purpose architecture."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_user_requirements_general_purpose.xml:39(term)
msgid "Time to market"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_user_requirements_general_purpose.xml:41(para)
msgid "The ability to deliver services or products within a flexible time frame is a common business factor when building a general purpose cloud. Delivering a product in six months instead of two years is a driving force behind the decision to build general purpose clouds. General purpose clouds allow users to self-provision and gain access to compute, network, and storage resources on-demand thus decreasing time to market."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_user_requirements_general_purpose.xml:55(para)
msgid "Revenue opportunities for a cloud will vary greatly based on the intended use case of that particular cloud. Some general purpose clouds are built for commercial customer facing products, but there are alternatives that might make the general purpose cloud the right choice."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_user_requirements_general_purpose.xml:66(title)
msgid "Technical requirements"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_user_requirements_general_purpose.xml:67(para)
msgid "Technical cloud architecture requirements should be weighted against the business requirements."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_user_requirements_general_purpose.xml:74(para)
msgid "As a baseline product, general purpose clouds do not provide optimized performance for any particular function. While a general purpose cloud should provide enough performance to satisfy average user considerations, performance is not a general purpose cloud customer driver."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_user_requirements_general_purpose.xml:83(term)
msgid "No predefined usage model"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_user_requirements_general_purpose.xml:85(para)
msgid "The lack of a pre-defined usage model enables the user to run a wide variety of applications without having to know the application requirements in advance. This provides a degree of independence and flexibility that no other cloud scenarios are able to provide."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_user_requirements_general_purpose.xml:94(term)
msgid "On-demand and self-service application"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_user_requirements_general_purpose.xml:96(para)
msgid "By definition, a cloud provides end users with the ability to self-provision computing power, storage, networks, and software in a simple and flexible way. The user must be able to scale their resources up to a substantial level without disrupting the underlying host operations. One of the benefits of using a general purpose cloud architecture is the ability to start with limited resources and increase them over time as the user demand grows."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_user_requirements_general_purpose.xml:109(term)
msgid "Public cloud"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_user_requirements_general_purpose.xml:111(para)
msgid "For a company interested in building a commercial public cloud offering based on OpenStack, the general purpose architecture model might be the best choice. Designers are not always going to know the purposes or workloads for which the end users will use the cloud."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_user_requirements_general_purpose.xml:120(term)
msgid "Internal consumption (private) cloud"
msgstr ""

#: ./doc/arch-design/generalpurpose/section_user_requirements_general_purpose.xml:122(para)
msgid "Organizations need to determine if it is logical to create their own clouds internally. Using a private cloud, organizations are able to maintain complete control over architectural and cloud components."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_user_requirements_general_purpose.xml:127(para)
msgid "Users will want to combine using the internal cloud with access to an external cloud. If that case is likely, it might be worth exploring the possibility of taking a multi-cloud approach with regard to at least some of the architectural elements."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_user_requirements_general_purpose.xml:135(para)
msgid "Designs that incorporate the use of multiple clouds, such as a private cloud and a public cloud offering, are described in the \"Multi-Cloud\" scenario, see <xref linkend=\"multi_site\"/>."
msgstr ""

#: ./doc/arch-design/generalpurpose/section_user_requirements_general_purpose.xml:145(para)
msgid "Security should be implemented according to asset, threat, and vulnerability risk assessment matrices. For cloud domains that require increased computer security, network security, or information security, a general purpose cloud is not considered an appropriate choice."
msgstr ""

#. Put one translator per line, in the form of NAME <EMAIL>, YEAR1, YEAR2
#: ./doc/arch-design/generalpurpose/section_user_requirements_general_purpose.xml:0(None)
msgid "translator-credits"
msgstr ""