Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. absolute limit Impassable limits for nova VMs. Settings include total RAM size, maximum number of vCPUs, and maximum disk size. access control list A list of permissions attached to an object. An ACL specifies which users or system processes have access to objects. It also defines which operations can be performed on specified objects. Each entry in a typical ACL specifies a subject and an operation. For instance, ACL entry, (Alice, delete), for a file gives Alice permission to delete the file. access key Alternative term for an Amazon EC2 access key. See EC2 Access key. account The swift context of an account. Do not confuse with a user account from an identity service such as Active Directory, /etc/passwd, OpenLDAP, keystone, and so on. account auditor Checks for missing replicas, incorrect, and corrupted objects in a specified swift account by running queries against the back-end SQLite database. account database A SQLite database that contains swift accounts and related metadata and is accessed by the accounts server. account reaper A swift worker that scans for and deletes account databases that are marked for deletion on an account server. account server Lists containers in swift and stores container information in the account database. account service A swift component that provides account services such as list, create, modify, and audit. Do not confuse with keystone, OpenLDAP, or similar user account services. accounting Nova provides accounting information through the event notification and system usage data facilities. ACL See access control list. Active Directory Authentication and Identity Service by Microsoft, based on LDAP. Supported in OpenStack. address pool A group of fixed and/or floating IP addresses that are assigned to a nova project and can be used by or assigned to the VM instances in a project. admin API A subset of API calls that are accessible to authorized administrators and are generally not accessible to end users or the public internet, can exist as a separate service (keystone) or can be a subset of another API (nova). admin server In the context of keystone, the worker process that provides access to the admin API. Advanced Message Queuing Protocol (AMQP) The open standard messaging protocol used by nova for intra-service communications, provided by RabbitMQ (the default), Qpid, or ZeroMQ. Advanced RISC Machine (ARM) Lower power consumption CPU often found in mobile and embedded devices. Supported by OpenStack. alert Nova can send alerts through its notification system, which includes a facility to create custom notification drivers. Alerts can be sent to and displayed on the horizon dashboard. allocate The process of taking floating IP address from the address pool so it can be associated with a fixed IP on a nova VM instance. Amazon Kernel Image (AKI) Both a VM container format and disk format. Supported by glance. Amazon Machine Image (AMI) Both a VM container format and disk format. Supported by glance. Amazon Ramdisk Image (ARI) Both a VM container format and disk format. Supported by glance. AMQP Advanced Message Queue Protocol. An open Internet protocol for reliably sending and receiving messages. It enables building a diverse, coherent messaging ecosystem. Anvil A project that ports the shell script-based project named devstack to Python. Apache The Apache Software Foundation supports the Apache community of open-source software projects. These projects provide software products for the public good. Apache License 2.0 All OpenStack core projects are provided under the terms of the Apache License 2.0 license. Apache Web Server The most common web server software currently used on the Internet. API Application programming interface. API endpoint The daemon, worker, or service that a client communicates with to access an API. API endpoints can provide any number of services such as keystone authentication, sales data, performance metrics, nova VM commands, census data, and so on. API extension A nova and neutron feature that allows custom modules to extend the core APIs. API extension plug-in Alternative term for a neutron plug-in or neutron API extension. API key Alternative term for an API token. API server Any node running a daemon or worker that provides an API endpoint. API token Passed to API requests and used by OpenStack to verify that the client is authorized to run the requested operation. API version In OpenStack, a the API version for a project is part of the URL. For example, example.com/nova/v1/foobar. applet A Java program that can be embedded into a web page. Application Programming Interface (API) A collection of specifications used to access a service, application, or program. Includes service calls, required parameters for each call, and the expected return values. application server A piece of software that makes available another piece of software over a network. Application Service Provider (ASP) Companies that rent specialized applications that help businesses and organizations provide additional services with less cost. arptables Used along with iptables, ebtables, and ip6tables in nova to provide firewall services. associate The process associating a nova floating IP address to a fixed IP address. Asynchronous JavaScript and XML (AJAX) A group of interrelated web development techniques used on the client-side to create asynchronous web applications. Used extensively in horizon. ATA over Ethernet (AoE) A disk storage protocol tunneled within Ethernet. Currently not supported in nova. attach The process of connecting a VIF or vNIC to a L2 network in neutron. In the context of nova, this process connects a storage volume to an instance. attachment (network) Association of an interface ID to a logical port. Plugs an interface into a port. auditing Provided in nova through the system usage data facility. auditor A worker processes that verifies the integrity of swift objects, containers, and accounts. Auditors is the collective term for the swift account auditor, container auditor, and object auditor. Austin Project name for the initial release of OpenStack. auth node Alternative term for a swift authorization node. authentication The process that confirms that the user, process, or client is really who they say they are through private key, secret token, password, fingerprint, or similar method. authentication token A string of text provided to the client after authentication. Must be provided by the user or process in subsequent requests to the API endpoint. AuthN The keystone component that provides authentication services. authorization The act of verifying that a user, process, or client is authorized to perform an action, such as delete a swift object, list a swift container, start a nova VM, reset a password, and so on. authorization node A swift node that provides authorization services. AuthZ The keystone component that provides high-level authorization services. Auto ACK Configuration setting within RabbitMQ that enables or disables message acknowledgment. Enabled by default. auto declare A nova RabbitMQ setting that determines if a message exchange is automatically created when the program starts. availability zone An Amazon EC2 concept of an isolated area that is used for fault tolerance. Do not confuse with an OpenStack nova zone or cell. AWS Amazon Web Services. back-end Interactions and processes that are obfuscated from the user, such as nova mounting a volume, a daemon sending data to an iSCSI target, or swift checking the integrity of an object. back-end catalog The storage method used by the keystone catalog service to store and retrieve information about API endpoints that are available to the client. Examples include a SQL database, LDAP database, or KVS back-end. back-end store The persistent data store used to save and retrieve a information for a service, such as a listing of swift objects, the current state of a nova VM, a list of user names, and so on. Method that glance uses to retrieve and store VM images. Options include swift, local file system, S3, and HTTP. bandwidth The amount of available data used by communication resources such as the Internet. Represents the amount of data that is used to download things or the amount of data available to download. bare A glance container format that indicates that no container exists for the VM image. base image An OpenStack-provided image. Bexar A grouped release of projects related to OpenStack that came out in February of 2011. It included Compute (nova) and Object Storage (swift) only. binary Information that consists solely of ones and zeroes, which is the language of computers. bit A bit is a single digit number that is in base of 2 (either a zero or one). Bandwidth usage is measured in bits-per-second. bit-per-second (BPS) The universal measurement of how quickly data is transferred from place to place. block device A device that moves data in the form of blocks. These device nodes interface the devices, such as hard disks, CD-ROM drives, flash drives, and other addressable regions of memory. block migration A method of VM live migration used by KVM to evacuate instances from one host to another with very little downtime during a user-initiated switch-over. Does not require shared storage. Supported by nova. BMC Baseboard Management Controller. The intelligence in the IPMI architecture, which is a specialized micro-controller that is embedded on the motherboard of a computer and acts as a server. Manages the interface between system management software and platform hardware. bootable disk image A type of VM image that exists as a single, bootable file. Bootstrap Protocol (BOOTP) A network protocol used by a network client to obtain an IP address from a configuration server. Provided in nova through the dnsmasq daemon when using either the FlatDHCP manager or VLAN manager network manager. browser Any client software that allows a computer or device to access the Internet. builder file Contains configuration information for a swift ring, and is used to re-configure the ring or to recreate it from scratch after a serious failure. button class A group of related button types within horizon. Buttons to start, stop, and suspend VMs are in one class. Buttons to associate and disassociate floating IP addresses are in another class, and so on. byte Set of bits that make up a single character; there are usually 8 bits to a byte. CA Certificate Authority or Certification Authority. In cryptography, an entity that issues digital certificates. The digital certificate certifies the ownership of a public key by the named subject of the certificate. This allows others (relying parties) to rely upon signatures or assertions made by the private key that corresponds to the certified public key. In this model of trust relationships, a CA is a trusted third party for both the subject (owner) of the certificate and the party relying upon the certificate. CAs are characteristic of many public key infrastructure (PKI) schemes. cache pruner An executable program that is used to keep a glance VM image cache at or below its configured maximum size. Cactus An OpenStack grouped release of projects that came out in the spring of 2011. It included Compute (nova), Object Storage (swift), and the Image service (glance). CALL One of the RPC primitives used by the OpenStack message queue software. Sends a message and waits for a response. capability Defines resources for a cell, including CPU, storage, and networking. Can apply to the specific services within a cell or a whole cell. capacity cache A table within the nova back-end database that contains the current workload, amount of free RAM, number of VMs running on each host. Used to determine on which VM a host starts. capacity updater A notification driver that monitors VM instances and updates the capacity cache as needed. CAST One of the RPC primitives used by the OpenStack message queue software. Sends a message and does not wait for a response. catalog Contains a list of available API endpoints to a user after they authenticate to keystone. catalog service A keystone service that provides a list of available API endpoints to a user after they authenticate to keystone. Ceilometer An incubated project that provides metering and billing facilities for OpenStack. cell Provides logical partitioning of nova resources in a child and parent relationship. Requests are passed from parent cells to child cells if the parent cannot provide the requested resource. cell forwarding A nova option that allows parent cells to pass resource requests to child cells if the parent cannot provide the requested resource. cell manager The nova component that contains a list of the current capabilities of each host within the cell and routes requests as appropriate. CentOS A Linux distribution that is compatible with OpenStack. Ceph Massively scalable distributed storage system that consists of an object store, block store, and POSIX-compatible distributed file system. Compatible with OpenStack. CephFS The POSIX-compliant file system provided by Ceph. certificate authority A simple certificate authority provided by nova for cloudpipe VPNs and VM image decryption. Challenge-Handshake Authentication Protocol (CHAP) An iSCSI authentication method supported by nova. chance scheduler A scheduling method used by nova that randomly chooses an available host from the pool. changes since A nova API parameter that allows you to download changes to the requested item since your last request, instead of downloading a new, fresh set of data and comparing it against the old data. Chef An operating system configuration management tool supporting OpenStack deployments. child cell If a requested resource such as CPU time, disk storage, or memory is not available in the parent cell, the request is forwarded to its associated child cells. If the child cell can fulfill the request, it does. Otherwise, it attempts to pass the request to any of its children. Cinder A core OpenStack project that maintains the nova Volume Service for VMs. Cisco neutron plug-in A neutron plug-in for Cisco devices and technologies including UCS and Nexus. cloud architect A person who plans, designs, and oversees the creation of clouds. cloud computing A model that enables access to a shared pool of configurable computing resources, such as networks, servers, storage, applications, and services, that can be rapidly provisioned and released with minimal management effort or service provider interaction. cloud controller Collection of nova components that represent the global state of the cloud, talks to services such as keystone authentication, swift object storage, and node/storage workers through a queue. cloud controller node A node that runs network, volume, API, scheduler and image services. Each service may be broken out into separate nodes for scalability or availability. Cloud Data Management Interface (CDMI) SINA standard that defines a RESTful API for managing objects in the cloud, currently unsupported in OpenStack. Cloud Infrastructure Management Interface (CIMI) An in-progress specification for cloud management. Currently unsupported in OpenStack. cloud-init A package commonly installed in VM images that performs initialization of an instance after boot using information that it retrieves from the metadata service such as the SSH public key and user data. cloudadmin One of the default roles in the nova RBAC system. Allows for complete system access. cloudpipe A service in nova used to create VPNs on a per-project basis. cloudpipe image A pre-made VM image that serves as a cloudpipe server. Essentially, OpenVPN running on Linux. CMDB Configuration Management Database. command filter Lists allowed commands within the nova rootwrap facility. community project A project that is not officially endorsed by the OpenStack Foundation. If the project is successful enough, it might be elevated to an incubated project and then to a core project, or it might be merged with the main code trunk. compression OpenStack supports compression at the Linux file system level but does not support compression for things such as swift objects or glance VM images. Compute API The nova-api daemon that provides access to nova services. Can communicate with other APIs, such as the Amazon EC2 API. Compute API extension Alternative term for a nova API extension. compute controller The nova component that chooses suitable hosts on which to start VM instances. compute host Physical host dedicated to running compute nodes. compute node A node that runs the nova-compute daemon, a VM instance that provides a wide range of services such as a web services and analytics. compute service Alternative term for the nova component that manages VMs. compute worker The nova component that runs on each compute node and manages the VM instance life cycle, including run, reboot, terminate, attach/detach volumes, and so on. Provided by the nova-compute daemon. concatenated object A segmented large object within swift that is put back together again and then sent to the client. consistency window The amount of time it takes for a new swift object to become accessible to all clients. console log Contains the output from a Linux VM console in nova. container Used to organize and store objects within swift, similar to the concept as a Linux directory but cannot be nested. Alternative term for a glance container format. container auditor Checks for missing replicas or incorrect objects in the specified swift containers through queries to the SQLite back-end database. container database A SQLite database that contains swift containers and related metadata and is accessed by the container server container format The "envelope" used by glance to store a VM image and its associated metadata, such as machine state, OS disk size, and so on. container server A swift that manages containers. container service The swift component that provides container services, such as create, delete, list, and so on. controller node Alternative term for a cloud controller node. core API Depending on context, the core API is either the OpenStack API or the main API of a specific core project, such as nova, neutron, glance, and so on. core project An official OpenStack project. Currently consists of Compute (nova), Object Storage (swift), Image Service (glance), Identity (keystone), Dashboard (horizon), Networking (neutron), and Volume (cinder). cost Under the nova distributed scheduler this is calculated by looking at the capabilities of each host relative to the flavor of the VM instance being requested. credentials Data that is only known to or accessible by a user that is used to verify the user is who they say they are and presented to the server during authentication. Examples include a password, secret key, digital certificate, fingerprint, and so on. Crowbar An open source community project by Dell that aims to provide all necessary services to quickly deploy clouds. current workload An element of the nova capacity cache that is calculated based on the number of build, snapshot, migrate, and resize operations currently in progress on a given host. customer Alternative term for tenant. customization module A user-created Python module that is loaded by horizon to change the look and feel of the dashboard. daemon A process that runs in the background and waits for requests. May or may not listen on a TCP or UDP port. Do not confuse with a worker. DAC Discretionary access control. Governs the ability of subjects to access objects, while enabling users to make policy decisions and assign security attributes. The traditional UNIX system of users, groups, and read-write-execute permissions is an example of DAC. dashboard The web-based management interface for OpenStack. An alternative name for horizon. data encryption Both glance and nova support encrypted virtual machine (VM) images (but not instances). In-transit data encryption is supported in OpenStack using technologies such as HTTPS, SSL, TLS, SSH. swift does not support object encryption at the application level but may support storage that uses disk encryption. database ID A unique ID given to each replica of a swift database. database replicator A swift component that copies changes in the account, container, and object databases to other nodes. deallocate The process of removing the association between a floating IP address and a fixed IP address thus returning the floating IP to the address pool. Debian A Linux distribution that is compatible with OpenStack. deduplication The process of finding duplicate data at the disk block, file, and/or object level to minimize storage use, currently unsupported within OpenStack. default panel The default panel that is displayed when a user accesses the horizon dashboard. default tenant New users are assigned to this keystone tenant if no tenant is specified when a user is created. default token A keystone token that is not associated with a specific tenant and is exchanged for a scoped token. delayed delete An option within glance so that rather than immediately delete an image, it is deleted after a pre-defined number of seconds. delivery mode Setting for the nova RabbitMQ message delivery mode, can be set to either transient or persistent. deprecated auth An option within nova that allows administrators to create and manage users through the nova-manage command as opposed to using keystone. developer One of the default roles in the nova RBAC system and is the default role assigned to a new user. device In the context of swift this refers to the underlying storage device. device ID Maps swift partitions to physical storage devices. device weight Used to distribute the partitions among swift devices. The distribution is usually proportional to the storage capacity of the device. DevStack Community project that uses shell scripts to quickly build complete OpenStack development environments. DHCP Dynamic Host Configuration Protocol. A network protocol that configures devices that are connected to a network so they can communicate on that network by using the Internet Protocol (IP). The protocol is implemented in a client-server model where DHCP clients request configuration data such as, an IP address, a default route, and one or more DNS server addresses from a DHCP server. Diablo A grouped release of projects related to OpenStack that came out in the fall of 2011, the fourth release of OpenStack. It included Compute (nova 2011.3), Object Storage (swift 1.4.3), and the Image service (glance). direct consumer An element of the nova RabbitMQ that comes to life when a RPC call is executed. It connects to a direct exchange through a unique exclusive queue, sends the message, and terminates. direct exchange A routing table that is created within the nova RabbitMQ during RPC calls, one is created for each RPC call that is invoked. direct publisher Element of RabbitMQ that provides a response to an incoming MQ message. disassociate The process of removing the association between a floating IP address and fixed IP and thus returning the floating IP address to the address pool. disk encryption The ability to encrypt data at the file system, disk partition or whole disk level. Supported within nova VMs. disk format The underlying format that a disk image for a VM is stored as within the glance back-end store. For example, AMI, ISO, QCOW2, VMDK, and so on. dispersion In swift, tools to test and ensure dispersion of objects and containers to ensure fault tolerance. Django A web framework used extensively in horizon. DNS Domain Name Server. A hierarchical and distributed naming system for computers, services, and resources connected to the Internet or a private network. Associates a human-friendly names to IP addresses. DNS record A record that specifies information about a particular domain and belongs to the domain. dnsmasq Daemon that provides DNS, DHCP, BOOTP, and TFTP services, used by the nova VLAN manager and FlatDHCP manager. domain Separates a web site from other sites. Often, the domain name has two or more parts that are separated by dots. For example, yahoo.com, usa.gov, Harvard.edu, or mail.yahoo.com. A domain is an entity or container of all DNS-related information containing one or more records. Domain Name Service (DNS) In nova, the support that enables associating DNS entries with floating IP addresses, nodes, or cells so host names are consistent across reboots. Domain Name System (DNS) A system by which Internet domain name-to-address and address-to-name resolutions are determined. DNS helps navigate the Internet by translating the IP address into an address that is easier to remember For example, translating 111.111.111.1 into www.yahoo.com. All domains and their components, such as mail servers, utilize DNS to resolve to the appropriate locations. DNS servers are usually set up in a master-slave relationship such that failure of the master invokes the slave. DNS servers might also be clustered or replicated such that changes made to one DNS server are automatically propagated to other active servers. download The transfer of data, usually in the form of files, from one computer to another. DRTM Dynamic root of trust measurement. durable exchange The nova RabbitMQ message exchange that remains active when the server restarts. durable queue A nova RabbitMQ message queue that remains active when the server restarts. Dynamic Host Configuration Protocol (DHCP) A method to automatically configure networking for a host at boot time. Provided by both neutron and nova. Dynamic HyperText Markup Language (DHTML) Used to refer to pages that use HTML, JavaScript, and CCS to allow users to interact with a web page or show simple animation. EBS boot volume An Amazon EBS storage volume that contains a bootable VM image, currently unsupported in OpenStack. ebtables Used in nova along with arptables, iptables, and ip6tables to create firewalls and to ensure isolation of network communications. EC2 The Amazon commercial compute product, similar to nova. EC2 access key Used along with an EC2 secret key to access the nova EC2 API. EC2 API OpenStack supports accessing the Amazon EC2 API through nova. EC2 Compatibility API A nova component that allows OpenStack to communicate with Amazon EC2 EC2 secret key Used along with an EC2 access key when communicating with the nova EC2 API, is used to digitally sign each request. Elastic Block Storage (EBS) The Amazon commercial block storage product. encryption OpenStack supports encryption technologies such as HTTPS, SSH, SSL, TLS, digital certificates, and data encryption. endpoint See API endpoint. endpoint registry Alternative term for a keystone catalog. endpoint template A list of URL and port number endpoints that indicate where a service, such as object storage, compute, identity, and so on, can be accessed. entity Any piece of hardware or software that wants to connect to the network services provided by neutron, the Network Connectivity service. An entity can make use of neutron by implementing a VIF. ephemeral image A VM image that does not save changes made to its volumes and reverts them to their original state after the instance is terminated. ephemeral volume Volume that does not save the changes made to it and reverts to its original state when the current user relinquishes control. Essex A grouped release of projects related to OpenStack that came out in April 2012, the fifth release of OpenStack. It included Compute (nova 2012.1), Object Storage (swift 1.4.8), Image (glance), Identity (keystone), and Dashboard (horizon). ESX An OpenStack-supported hypervisor. ESXi An OpenStack-supported hypervisor. ETag MD5 hash of an object within swift, used to ensure data integrity. euca2ools A collection of command line tools for administering VMs, most are compatible with OpenStack. Eucalyptus Kernel Image (EKI) Used along with an ERI to create an EMI. Eucalyptus Machine Image (EMI) VM image container format supported by glance. Eucalyptus Ramdisk Image (ERI) Used along with an EKI to create an EMI. evacuate The process of migrating one or all virtual machine (VM) instances from one host to another, compatible with both shared storage live migration and block migration. exchange Alternative term for a RabbitMQ message exchange. exchange type A routing algorithm in the nova RabbitMQ. exclusive queue Connected to by a direct consumer in RabbitMQ / nova, the message can only be consumed by the current connection. extended attributes (xattrs) File system option that allows for storage of additional information beyond owner, group, permissions, modification time, and so on. The underlying swift file system must support extended attributes. extension Alternative term for a nova API extension or plug-in. In the context of keystone this is a call that is specific to the implementation, such as adding support for OpenID. extra specs Allows additional requirements to be specified when nova determines where to start a new instance, examples include a minimum amount of network bandwidth or a GPU. FakeLDAP An easy method to create a local LDAP directory for testing keystone and nova. Requires Redis. fan-out exchange Within RabbitMQ and nova it is the messaging interface that is used by the scheduler service to receive capability messages from the compute, volume, and network nodes. Fedora A Linux distribution compatible with OpenStack. Fibre Channel Storage protocol similar in concept to TCP/IP, encapsulates SCSI commands and data. Fibre Channel over Ethernet (FCoE) The fibre channel protocol tunneled within Ethernet. fill-first scheduler The nova scheduling method that attempts to fill a host with VMs rather than starting new VMs on a variety of hosts. filter The step in the nova scheduling process when hosts that cannot run VMs are eliminated and not chosen. firewall Used to restrict communications between hosts and/or nodes, implemented in nova using iptables, arptables, ip6tables and etables. fixed IP address An IP address that is associated with the same instance each time that instance boots, generally not accessible to end users or the public internet, used for management of the instance. Flat Manager The nova component that gives IP addresses to authorized nodes and assumes DHCP, DNS, and routing configuration and services are provided by something else. flat mode injection A nova networking method where the OS network configuration information is injected into the VM image before the instance starts. flat network The Network Controller provides virtual networks to enable compute servers to interact with each other and with the public network. All machines must have a public and private network interface. A flat network is a private network interface, which is controlled by the flat_interface option with flat managers. FlatDHCP Manager The nova component that provides dnsmasq (DHCP, DNS, BOOTP, TFTP) and radvd (routing) services. flavor Alternative term for a VM instance type. flavor ID UUID for each nova or glance VM flavor or instance type. floating IP address An IP address that a nova project can associate with a VM so the instance has the same public IP address each time that it boots. You create a pool of floating IP addresses and assign them to instances as they are launched to maintain a consistent IP address for maintaining DNS assignment. Folsom A grouped release of projects related to OpenStack that came out in the fall of 2012, the sixth release of OpenStack. It includes Compute (nova), Object Storage (swift), Identity (keystone), Networking (neutron), Image service (glance) and Volumes or Block Storage (cinder). FormPost swift middleware that allows users to upload (post) an image through a form on a web page. front-end The point where a user interacts with a service, can be an API endpoint, the horizon dashboard, or a command line tool. gateway Hardware or software that translates between two different protocols. Glance A core project that provides the OpenStack Image Service. glance API server Processes client requests for VMs, updates glance metadata on the registry server, and communicates with the store adapter to upload VM images from the back-end store. glance registry Alternative term for the glance image registry. global endpoint template The keystone endpoint template that contains services available to all tenants. GlusterFS A file system designed to aggregate NAS hosts, compatible with OpenStack. golden image A method of operating system installation where a finalized disk image is created and then used by all nodes without modification. Graphic Interchange Format (GIF) A type of image file that is commonly used for animated images on web pages. Graphics Processing Unit (GPU) Choosing a host based on the existence of a GPU is currently unsupported in OpenStack. Green Threads The cooperative threading model used by Python, reduces race conditions, and only context switches when specific library calls are made. Each OpenStack service is its own thread. Grizzly Project name for the seventh release of OpenStack. guest OS An operating system instance running under the control of a hypervisor. handover An object state in swift where a new replica of the object is automatically created due to a drive failure. hard reboot A type of reboot where a physical or virtual power button is pressed as opposed to a graceful, proper shutdown of the operating system. Heat An integrated project that aims to orchestrate multiple cloud applications for OpenStack. Horizon The OpenStack project that provides a dashboard, which is a web interface. horizon plugin A plugin for the OpenStack dashboard (horizon). host A physical computer, not a VM instance (node). host aggregate A method to further subdivide availability zones into hypervisor pools, a collection of common hosts. Host Bus Adapter (HBA) Device plugged into a PCI slot such as a fibre channel or network card. HTTP Hypertext Transfer Protocol. HTTP is an application protocol for distributed, collaborative, hypermedia information systems. It is the foundation of data communication for the World Wide Web. Hypertext is structured text that uses logical links (hyperlinks) between nodes containing text. HTTP is the protocol to exchange or transfer hypertext. HTTPS Hypertext Transfer Protocol Secure (HTTPS) is a communications protocol for secure communication over a computer network, with especially wide deployment on the Internet. Technically, it is not a protocol in and of itself; rather, it is the result of simply layering the Hypertext Transfer Protocol (HTTP) on top of the SSL/TLS protocol, thus adding the security capabilities of SSL/TLS to standard HTTP communications. Hyper-V One of the hypervisors supported by OpenStack. hyperlink Any kind of text that contains a link to some other site, commonly found in documents where clicking on a word or words opens up a different web site. HyperText Transfer Protocol (HTTP) The protocol that tells browsers where to go to find information. Hypertext Transfer Protocol Secure (HTTPS) Encrypted HTTP communications using SSL or TLS, most OpenStack API endpoints and many inter-component communications support HTTPS communication. hypervisor Software that arbitrates and controls VM access to the actual underlying hardware. hypervisor pool A collection of hypervisors grouped together through host aggregates. IaaS Infrastructure as a Service. IaaS is a provision model in which an organization outsources the equipment used to support operations, including storage, hardware, servers and networking components. The service provider owns the equipment and is responsible for housing, running and maintaining it. The client typically pays on a per-use basis. IaaS is a model for providing cloud services. ID number Unique numeric ID associated with each user in keystone, conceptually similar to a Linux or LDAP UID. Identity API Alternative term for the Identity Service API. Identity back-end The source used by keystone to retrieve user information an OpenLDAP server for example. Identity Service The identity service provided by the keystone project. Identity Service API The API used to access the OpenStack Identity Service provided through keystone. IDS Intrusion Detection System image A collection of files for a specific operating system (OS) that you use to create or rebuild a server. OpenStack provides pre-built images. You can also create custom images, or snapshots, from servers that you have launched. Custom images can be used for data backups or as "gold" images for additional servers. Image API The glance API endpoint for management of VM images. image cache Used by glance to allow images on the local host to be used rather than re-downloading them from the image server each time one is requested. image ID Combination of URI and UUID used to access glance VM images through the image API. image membership A list of tenants that can access a given VM image within glance. image owner The keystone tenant who owns a glance virtual machine image. image registry A list of VM images that are available through glance. Image Service API Alternative name for the glance image API. image status The current status of a VM image in glance, not to be confused with the status of a running instance. image store The back-end store used by glance to store VM images, options include swift, local file system, S3, or HTTP. image UUID UUID used by glance to uniquely identify each VM image. incubated project A community project may be elevated to this status and is then promoted to a core project. ingress filtering The process of filtering incoming network traffic. Supported by nova. injection The process of putting a file into a virtual machine image before the instance is started. instance A running VM, or a VM in a known state such as suspended that can be used like a hardware server. instance ID Alternative term for instance UUID. instance state The current state of a nova VM image. instance type Describes the parameters of the various virtual machine images that are available to users, includes parameters such as CPU, storage, and memory. Alternative term for flavor. instance type ID Alternative term for a flavor ID. instance UUID Unique ID assigned to each nova VM instance. interface ID Unique ID for a neutron VIF or vNIC in the form of a UUID. Internet Service Provider (ISP) Any business that provides Internet access to individuals or businesses. IP address Number that is unique to every computer system on the Internet. Two versions of the Internet Protocol (IP) are in use for addresses: IPv4 and IPv6. IP Address Management (IPAM) The process of automating IP address allocation, deallocation, and management. Currently provided by nova, melange, and neutron. IPL Initial Program Loader. IPMI Intelligent Platform Management Interface. IPMI is a standardized computer system interface used by system administrators for out-of-band management of computer systems and monitoring of their operation. In layman's terms, it is a way to manage a computer using a direct network connection, whether it is turned on or not; connecting to the hardware rather than an operating system or login shell. iptables Used along with arptables and ebtables, iptables create firewalls in nova. iptables are the tables provided by the Linux kernel firewall (implemented as different Netfilter modules) and the chains and rules it stores. Different kernel modules and programs are currently used for different protocols; iptables applies to IPv4, ip6tables to IPv6, arptables to ARP, and ebtables to Ethernet frames. Requires root privilege to manipulate. iSCSI The SCSI disk protocol tunneled within Ethernet, supported by nova, swift, and glance. ISO9960 One of the VM image disk formats supported by glance. itsec A default roles in the nova RBAC system that allows the user to quarantine an instance in any project. Java A programming language that is used to create systems that involve more than one computer by way of a network. JavaScript A scripting language that is used to build web pages. JavaScript Object Notation (JSON) One of the supported response formats in OpenStack. Jenkins Tool used to run jobs automatically for OpenStack development. kernel-based VM (KVM) An OpenStack-supported hypervisor. Keystone The project that provides OpenStack Identity services. Kickstart A tool to automate system configuration and installation on Red Hat, Fedora, and CentOS based Linux distributions. large object An object within swift that is larger than 5 GBs. Launchpad The collaboration site for OpenStack. Layer-2 network Term used for OSI network architecture for the data link layer. libvirt Virtualization API library used by OpenStack to interact with many of its supported hypervisors. Linux bridge Software used to allow multiple VMs to share a single physical NIC within nova. Linux Bridge neutron plug-in Plugin that allows a Linux bridge to understand a neutron port, interface attachment, and other abstractions. Linux containers (LXC) An OpenStack-supported hypervisor. live migration The ability within nova to move running virtual machine instances from one host to another with only a small service interruption during switch-over. load balancer A load balancer is a logical device which belongs to a cloud account. It is used to distribute workloads between multiple back-end systems or services, based on the criteria defined as part of its configuration. load balancing The process of spreading client requests between two or more nodes to improve performance and availability. management API Alternative term for an admin API. management network A network segment used for administration, not accessible to the public internet. manager Logical groupings of related code such as the nova volume manager or network manager. manifest Used to track segments of a large object within swift. manifest object A special swift object that contains the manifest for a large object. Melange Project name for OpenStack Network Information Service. To be merged with neutron. membership The association between a glance VM image and a tenant, allows images to be shared with specified tenant(s). membership list A list of tenants that can access a given VM image within glance. memcached A distributed memory object caching system that is used by swift for caching. memory overcommit The ability to start new VM instances based on the actual memory usage of a host, as opposed to basing the decision on the amount of RAM each running instance thinks it has available. Also known as RAM overcommit. message broker The software package used to provide AMQP messaging capabilities within nova. Default package is RabbitMQ. message bus The main virtual communication line used by all AMQP messages for inter-cloud communications within nova. message queue Passes requests from clients to the appropriate workers and returns the output to the client after the job completes. Meta-Data Server (MDS) Stores CephFS metadata. migration The process of moving a VM instance from one host to another. Modular Layer 2 (ML2) neutron plug-in A Neutron plug-in that can concurrently use multiple layer 2 networking technologies such as 802.1Q and VXLAN. Monitor (Mon) A Ceph component that communicates with external clients, checks data state and consistency, and performs quorum functions. multi-factor authentication Authentication method that uses two or more credentials, such as a password and a private key. Currently not supported in keystone. MultiNic Facility in nova that allows each virtual machine instance to have more than one VIF connected to it. Nebula Released as open source by NASA in 2010 and is the basis for nova. netadmin One of the default roles in the nova RBAC system. Allows the user to allocate publicly accessible IP addresses to instances and change firewall rules. NetApp volume driver Allows nova to communicate with NetApp storage devices through the NetApp OnCommand Provisioning Manager. network A virtual network that provides connectivity between entities. For example, a collection of virtual ports that share network connectivity. In neutron terminology, a network is always a Layer-2 network. Network Address Translation (NAT) The process of modifying IP address information while in-transit. Supported by nova and neutron. network controller A nova daemon that orchestrates the network configuration of nodes including includes IP addresses, VLANs, bridging, and manages routing for both public and private networks. Network File System (NFS) A method for making file systems available over the network. Supported by OpenStack. network ID Unique ID assigned to each network segment within neutron. Same as network UUID network manager The nova component that manages various network components, such as firewall rules, IP address allocation, and so on. network node Any nova node that runs the network worker daemon. network segment Represents a virtual, isolated OSI layer 2 subnet in neutron. Network Time Protocol (NTP) A method of keeping a clock for a host or node correct through communications with a trusted, accurate time source. network UUID Unique ID for a neutron network segment. network worker The nova-network worker daemon, provides services such as giving an IP address to a booting nova instance. Neutron A core OpenStack project that provides a network connectivity abstraction layer to OpenStack Compute. neutron API API used to access neutron, provides and extensible architecture to allow custom plugin creation. neutron manager Allows nova and neutron integration thus allowing neutron to perform network management for nova VMs. neutron plugin Interface within neutron that allows organizations to create custom plugins for advanced features such as QoS, ACLs, or IDS. Nexenta volume driver Provides support for NexentaStor devices in nova. Nicira NVP neutron plugin Provides support for the Nicira Network Virtualization Platform (NVP) in neutron. No ACK Disables server-side message acknowledgment in the nova RabbitMQ. Increases performance but decreases reliability. node A VM instance that runs on a host. non-durable exchange Message exchange that is cleared when the service restarts. Its data is not written to persistent storage. non-durable queue Message queue that is cleared when the service restarts. Its data is not written to persistent storage. non-persistent volume Alternative term for an ephemeral volume. nova The OpenStack project that provides compute services. nova API Alternative term for the nova Compute API. nova network A nova component that manages IP address allocation, firewalls, and other network-related tasks. nova volume The nova component that manages storage volumes, currently being split off into a separate project named cinder. object A BLOB of data held by swift, can be in any format. Object API Alternative term for the swift object API. object auditor Opens all objects for an object server and verifies the MD5 hash, size, and metadata for each object. object expiration A configurable option within swift to automatically delete objects after a specified amount of time has passed or a certain date is reached. object hash Uniquely ID for a swift object. object path hash Used by swift to determine the location of an object in the ring. Maps objects to partitions. object replicator A swift component that copies and object to remote partitions for fault tolerance. object server A swift component that is responsible for managing objects. Object Service API Alternative term for the swift object API. object storage Provides eventually consistent and redundant storage and retrieval of fixed digital content. Object Storage Device (OSD) The Ceph storage daemon. object versioning Allows a user to set a flag on a swift container so all objects within the container are versioned. Oldie Term for a swift process that has been running for a long time, may be an indication of a hung process. Open Cloud Computing Interface (OCCI) A standardized interface for managing compute, data, and network resources, currently unsupported in OpenStack. Open Virtualization Format (OVF) Standard for packaging VM images. Supported in OpenStack. Open vSwitch neutron Plug-in A plugin for neutron used to provide support for Open vSwitch. OpenLDAP An open source LDAP server. Supported by both nova and keystone. OpenStack API (OSAPI) The core OpenStack API. openSUSE A Linux distribution that is compatible with OpenStack. operator The person responsible for planning and maintaining an OpenStack installation. orphan In the context of swift this is a process that is not terminated after an upgrade, restart, or reload of the service. parent cell If a requested resource, such as CPU time, disk storage, or memory, is not available in the parent cell, the request is forwarded to associated child cells. partition A unit of storage within swift used to store objects, exists on top of devices, replicated for fault tolerance. partition index Contains the locations of all swift partitions within the ring. partition shift value Used by swift to determine which partition data should reside on. pause A VM state where no changes occur (no changes in memory, network communications stop, etc), the VM is frozen but not shut down. PCI passthrough Allows guest VMs to have exclusive access to a PCI device, currently supported in OpenStack Havana and later releases. persistent message A message that is stored both in memory and on disk, the message is not lost after a failure or restart. persistent volume Changes to these types of disk volumes are saved. personality file A file used to customize a nova instance, can be used to inject SSH keys or a specific network configuration. plugin Software component providing the actual implementation for neutron APIs, or for Compute APIs, depending on the context. policy service Component of keystone that provides a rule management interface and a rule based authorization engine. port A virtual network port within neutron, VIFs / vNICs are connected to a port. port UUID Unique ID for a neutron port. preseed A tool to automate system configuration and installation on Debian-based Linux distributions. private image A glance VM image that is only available to specified tenants. private IP address An IP address used for management and administration, not available to the public internet. private network The Network Controller provides virtual networks to enable compute servers to interact with each other and with the public network. All machines must have a public and private network interface. A private network interface can be a flat or VLAN network interface. A flat network interface is controlled by the flat_interface with flat managers. A VLAN network interface is controlled by the vlan_interface option with VLAN managers. project A logical grouping of users within nova, used to define quotas and access to VM images. project ID User defined alpha-numeric string in nova, the name of a project. project VPN Alternative term for a cloudpipe. provider An administrator who has access to all hosts and instances. proxy node A node that provides the swift proxy service. proxy server Users of swift interact with the service through the proxy server which in-turn looks up the location of the requested data within the ring and returns the results to the user. public API An API endpoint used for both service to service communication and end user interactions. public image A glance VM image that is available to all tenants. public IP address An IP address that is accessible to end-users. public network The Network Controller provides virtual networks to enable compute servers to interact with each other and with the public network. All machines must have a public and private network interface. The public network interface is controlled by the public_interface option. Puppet An operating system configuration management tool supported by OpenStack. Python Programming language used extensively in OpenStack. QEMU Copy On Write 2 (QCOW2) One of the VM image disk formats supported by glance. Qpid Message queue software supported by OpenStack, an alternative to RabbitMQ. Neutron A core OpenStack project that provides a network connectivity abstraction layer to OpenStack Compute. neutron API API used to access neutron, provides and extensible architecture to allow custom plugin creation. neutron manager Allows nova and neutron integration thus allowing neutron to perform network management for nova VMs. neutron plugin Interface within neutron that allows organizations to create custom plugins for advanced features such as QoS, ACLs, or IDS. quarantine If swift finds objects, containers, or accounts that are corrupt they are placed in this state, are not replicated, cannot be read by clients, and a correct copy is re-replicated. Quick EMUlator (QEMU) QEMU is a generic and open source machine emulator and virtualizer. One of the hypervisors supported by OpenStack, generally used for development purposes. quota In nova, the ability to set resource limits on a per-project basis. RabbitMQ The default message queue software used by OpenStack. Rackspace Cloud Files Released as open source by Rackspace in 2010, the basis for swift. RADOS Block Device (RBD) Component of Ceph that allows a Linux block device to be striped over multiple distributed data stores. radvd The router advertisement daemon, used by the nova VLAN manager and FlatDHCP manager to provide routing services for VM instances. RAM filter The nova setting that allows or disallows RAM overcommitment. RAM overcommit The ability to start new VM instances based on the actual memory usage of a host, as opposed to basing the decision on the amount of RAM each running instance thinks it has available. Also known as memory overcommit. rate limit Configurable option within swift to limit database writes on a per-account and/or per-container basis. raw One of the VM image disk formats supported by glance, an unstructured disk image. rebalance The process of distributing swift partitions across all drives in the ring, used during initial ring creation and after ring reconfiguration. reboot Either a soft or hard reboot of a server. With a soft reboot, the operating system is signaled to restart, which allows for a graceful shutdown of all processes. A hard reboot is the equivalent of power cycling the server. The virtualization platform should ensure that the reboot action has completed successfully even in cases in which the underlying domain/vm is paused or halted/stopped. rebuild Removes all data on the server and replaces it with the specified image. Server ID and IP addresses remain the same. Recon A swift component that collects metrics. record Belongs to a particular domain and is used to specify information about the domain. There are several types of DNS records. Each record type contains particular information used to describe the purpose of that record. Examples include mail exchange (MX) records, which specify the mail server for a particular domain, and name server (NS) records, which specify the authoritative name servers for a domain. record ID A number within a database that is incremented each time a change is made. Used by swift when replicating. Red Dwarf Lite Community project that aims to provide database as a service. Red Hat Enterprise Linux (RHEL) A Linux distribution that is compatible with OpenStack. reference architecture A recommended architecture for an OpenStack cloud. region A Discrete OpenStack environment with dedicated API endpoints that typically shares only the Identity Service (keystone) with other regions. registry Alternative term for the glance image registry. registry server A glance service that provides VM image metadata information to clients. Reliable, Autonomic Distributed Object Store (RADOS) A collection of components that provides object storage within Ceph. Similar to swift. Remote Procedure Call (RPC) The method used by the nova RabbitMQ for intra-service communications. replica Provides data redundancy and fault tolerance by creating copies of swift objects, accounts, and containers so they are not lost when the underlying storage fails. replica count The number of replicas of the data in a swift ring. replication The process of copying data to a separate physical device for fault tolerance and performance. replicator The swift back-end process that creates and manages object replicas. request ID Unique ID assigned to each request sent to nova. rescue image A special type of VM image that is booted when an instance is placed into rescue mode. Allows an administrator to mount the file systems for an instance to correct the problem. resize Converts an existing server to a different flavor, in essence, scaling the server up or down. The original server is saved to allow rollback if there is a problem. All resizes must be tested and explicitly confirmed, at which time the original server is removed. RESTful A kind of web service API that uses REST, or Representational State Transfer. REST is the style of architecture for hypermedia systems that is used for the World Wide Web. ring An entity that maps swift data to partitions. A separate ring exists for each service, such as account, object, and container. ring builder Builds and manages rings within swift, assigns partitions to devices, and pushes the configuration to other storage nodes. Role Based Access Control (RBAC) Provides a predefined list of actions that the user can perform such as start or stop VMs, reset passwords, and so on. Supported in both keystone and nova and can be configured using the horizon dashboard. role ID Alpha-numeric ID assigned to each keystone role. rootwrap A feature of nova that allows the unprivileged "nova" user to run a specified list of commands as the Linux root user. round-robin scheduler Type of nova scheduler that evenly distributes instances among available hosts. routing key the nova direct exchanges, fanout exchanges, and topic exchanges use this to determine how to process a message, processing varies depending on exchange type. RPC driver Modular system that allows the nova underlying message queue software to be changed. For example, from RabbitMQ to ZeroMQ or Qpid. rsync Used by swift to push object replicas. RXTX cap Absolute limit on the amount of network traffic a nova VM instance can send and receive. RXTX quota Soft limit on the amount of network traffic a nova VM instance can send and receive. Ryu neutron plugin Allows the Ryu Network Operating System to function as a neutron OpenFlow controller. S3 Object storage service by Amazon, similar in function to swift, can act as a back-end store for glance VM images. scheduler manager A nova component that determines where VM instances should start. Uses modular design to support a variety of scheduler types. scoped token A keystone API access token that is associated with a specific tenant. scrubber Checks for and deletes unused VM, the component of glance that implements delayed delete. secret key String of text only known by the user, used along with an access key to make requests to the nova API. secure shell (SSH) Open source tool used to access remote hosts through an encrypted communications channel, SSH key injection is supported by nova. security group A set of network traffic filtering rules that are applied to a nova instance. segmented object A swift large object that has been broken up into pieces, the re-assembled object is called a concatenated object. server Computer that provides explicit services to the client software running on that system, often managing a variety of computer operations. A server is a VM instance in the compute system. Flavor and image are requisite elements when creating a server. server image Alternative term for a VM image. server UUID Unique ID assigned to each nova VM instance. service catalog Alternative term for the keystone catalog. service ID Unique ID assigned to each service that is available in the keystone catalog. service registration A keystone feature that allows services such as nova to automatically register with the catalog. service tenant Special keystone tenant that contains all services that are listed in the catalog. service token An administrator defined token used by nova to communicate securely with keystone. session back-end The method of storage used by horizon to track client sessions such as local memory, cookies, a database, or memcached. session persistence A feature of the load balancing service. It attempts to force subsequent connections to a service to be redirected to the same node as long as it is online. session storage A horizon component that stores and tracks client session information. Implemented through the Django sessions framework. shared IP address An IP address that can be assigned to a VM instance within the shared IP group. Public IP addresses can be shared across multiple servers for use in various high availability scenarios. When an IP address is shared to another server, the cloud network restrictions are modified to allow each server to listen to and respond on that IP address. You can optionally specify that the target server network configuration be modified. Shared IP addresses can be used with many standard heartbeat facilities, such as keepalive, that monitor for failure and manage IP failover. shared IP group A collection of servers that can share IPs with other members of the group. Any server in a group can share one or more public IPs with any other server in the group. With the exception of the first server in a shared IP group, servers must be launched into shared IP groups. A server may only be a member of one shared IP group. shared storage Block storage that is simultaneously accessible by multiple clients. For example, NFS. Sheepdog Distributed block storage system for QEMU, supported by OpenStack. Simple Cloud Identity Management (SCIM) Specification for managing identity in the cloud, currently unsupported by OpenStack. Single-root I/O Virtualization (SR-IOV) A specification that when implemented by a physical PCIe device allows it to be presented as multiple separate PCIe devices. This allows multiple virtualized guests to share direct access to the physical device, offering improved performance over an equivalent virtual device. Currently supported in OpenStack Havana and later releases. SmokeStack Runs automated tests against the core OpenStack API, written in Rails. snapshot A point-in-time copy of an OpenStack storage volume or image. Use storage volume snapshots to back up volumes. Use image snapshots to back up data, or as "gold" images for additional servers. soft reboot A controlled reboot where a VM instance is properly restarted through operating system commands. SolidFire Volume Driver The nova volume driver for the SolidFire iSCSI storage appliance. spread-first scheduler The nova VM scheduling algorithm that attempts to start new VM on the host with the least amount of load. SQL-Alchemy An open source SQL toolkit for Python, used in OpenStack. SQLite A lightweight SQL database, used as the default persistent storage method in many OpenStack services. StackTach Community project that captures nova AMQP communications, useful for debugging. static IP address Alternative term for a fixed IP address. StaticWeb WSGI middleware component of swift that serves container data as a static web page. storage back-end The method that a service uses for persistent storage such as iSCSI, NFS, or local disk. storage node A swift node that provides container services, account services, and object services, controls the account databases, container databases, and object storage. storage manager A XenAPI component that provides a pluggable interface to support a wide variety of persistent storage back-ends. storage manager back-end A persistent storage method supported by XenAPI such as iSCSI or NFS. storage services Collective name for the swift object services, container services, and account services. strategy Specifies the authentication source used by glance or keystone. subdomain A domain within a parent domain. Subdomains cannot be registered. Subdomains allow you to delegate domains. Subdomains can themselves have subdomains, so third-level, fourth-level, fifth-level, and deeper levels of nesting are possible. SUSE Linux Enterprise Server (SLES) A Linux distribution that is compatible with OpenStack. suspend Alternative term for a paused VM instance. swap Disk-based virtual memory, used by operating systems to provide more memory than is actually available on the system. swawth An authentication and authorization service for swift, implemented through WSGI middleware, uses swift itself as the persistent backing store. Swift An OpenStack core project that provides object storage services. swift All in One (SAIO) Creates a full swift development environment within a single VM. swift middleware Collective term for swift components that provide additional functionality. swift proxy server Acts as the gatekeeper to swift and is responsible for authenticating the user. swift storage node A node that runs swift account, container, and object services. sync point Point in time since the last container and accounts database sync among nodes within swift. sysadmin One of the default roles in the nova RBAC system, allows the user add other users to his or her project, interact with VM images that are associated with the project, and start and stop VM (VM) instances. system usage A nova component that, along with the notification system, collects metrics and usage information. Can be used for billing. TempAuth An authentication facility within swift that allows swift itself to perform authentication and authorization, frequently used in testing and development. Tempest Automated software test suite designed to run against the trunk of the OpenStack core project. TempURL A swift middleware component that allows a user to create URLs for temporary object access. tenant A group of users, used to isolate access to nova resources. An alternative term for a nova project. Tenant API An API that is accessible to tenants. tenant endpoint A keystone API endpoint that is associated with one or more tenants. tenant ID Unique ID assigned to each tenant within keystone, the nova project IDs map to the keystone tenant IDs. token An alpha-numeric string of text used to access OpenStack APIs and resources. token services A keystone component that manages and validates tokens after a user or tenant has been authenticated. tombstone Used to mark swift objects that have been deleted, ensures the object is not updated on another node after it has been deleted. topic publisher A process that is created when a RPC call is executed, used to push the message to the topic exchange. Torpedo Community project used to run automated tests against the OpenStack API. transaction ID Unique ID assigned to each swift request, used for debugging and tracing. transient Alternative term for non-durable. transient exchange Alternative term for a non-durable exchange. transient message A message that is stored in memory and is lost after the server is restarted. transient queue Alternative term for a non-durable queue. Ubuntu A Debian-based Linux distribution. unscoped token Alternative term for a keystone default token. updater Collective term for a group of swift components that processes queued and failed updates for containers and objects. user In keystone each user is associated with one or more tenants, and in nova they can be associated with roles, projects, or both. user data A blob of data that can be specified by the user when launching an instance. This data can be accessed by the instance through the metadata service or config drive. Commonly used for passing a shell script that is executed by the instance on boot. User Mode Linux (UML) An OpenStack-supported hypervisor. VIF UUID Unique ID assigned to each neutron VIF. Virtual Central Processing Unit (vCPU) Allows physical CPUs to be sub-divided and those divisions are then used by instances. Virtual Disk Image (VDI) One of the VM image disk formats supported by glance. Virtual Hard Disk (VHD) One of the VM image disk formats supported by glance. virtual IP An Internet Protocol (IP) address configured on the load balancer for use by clients connecting to a service that is load balanced. Incoming connections are distributed to back-end nodes based on the configuration of the load balancer. virtual machine (VM) An operating system instance that runs on top of a hypervisor. Multiple VMs can run at the same time on the same physical host. virtual network An L2 network segment within neutron. Virtual Network Computing (VNC) Open source GUI and CLI tools used for remote console access to VMs. Supported by nova. Virtual Network InterFace (VIF) An interface that is plugged into a port in a neutron network. Typically a virtual network interface belonging to a VM. virtual port Attachment point where a virtual interface connects to a virtual network. virtual private network (VPN) Provided by nova in the form of cloudpipes, specialized instances that are used to create VPNs on a per-project basis. virtual server Alternative term for a VM or guest. virtual switch (vSwitch) Software that runs on a host or node and provides the features and functions of a hardware based network switch. virtual VLAN Alternative term for a virtual network. VirtualBox An OpenStack-supported hypervisor. VLAN manager A nova component that provides dnsmasq, radvd, and sets up forwarding to and from cloudpipe instances. VLAN network The Network Controller provides virtual networks to enable compute servers to interact with each other and with the public network. All machines must have a public and private network interface. A VLAN network is a private network interface, which is controlled by the vlan_interface option with VLAN managers. VM disk (VMDK) One of the VM image disk formats supported by glance. VM image Alternative term for an image. VM Remote Control (VMRC) Method to access VM instance consoles using a web browser. Supported by nova. VMware API Supports interaction with VMware products in nova. VNC proxy A nova component that provides users access to the consoles of their VM instances through VNC or VMRC. volume Disk-based data storage generally represented as an iSCSI target with a file system that supports extended attributes, can be persistent or ephemeral. Volume API An API on a separate endpoint for attaching, detaching, and creating block storage for compute VMs. volume controller A nova component that oversees and coordinates storage volume actions. volume driver Alternative term for a volume plugin. volume ID Unique ID applied to each storage volume under the nova control. volume manager A nova component that creates, attaches, and detaches persistent storage volumes. volume node A nova node that runs the cinder-volume daemon. volume plugin A plugin for the nova volume manager. Provides support for a new and specialized types of back-end storage. Volume Service API Alternative term for the nova volume API. volume worker A cinder component that interacts with back-end storage to manage the creation and deletion of volumes and the creation of compute volumes, provided by the cinder-volume daemon. vSphere An OpenStack-supported hypervisor. weighing A nova process that determines the suitability of the VM instances for a job for a particular host. For example, not enough RAM on the host, too many CPUs on the host, and so on. weight Used by swift storage devices to determine which storage devices are suitable for the job. Devices are weighted by size. weighted cost The sum of each cost used when deciding where to start a new VM instance in nova. worker A daemon that listens to a queue and carries out tasks in response to messages. For example, the cinder-volume worker attaches storage to instances. Xen API The Xen administrative API, which is supported by nova. Xen Cloud Platform (XCP) An OpenStack-supported hypervisor. Xen Storage Manager Volume Driver A nova volume plugin that allows for communication with the Xen Storage Manager API. XenServer An OpenStack-supported hypervisor. ZeroMQ Message queue software supported by OpenStack, an alternative to RabbitMQ. Also spelled 0MQ. Zuul Tool used in OpenStack development to ensure correctly ordered testing of changes in parallel.