openstack-manuals/doc/install-guide/source/overview.rst

Overview

The OpenStack project is an open source cloud computing platform that supports all types of cloud environments. The project aims for simple implementation, massive scalability, and a rich set of features. Cloud computing experts from around the world contribute to the project.

OpenStack provides an Infrastructure-as-a-Service (IaaS)<IaaS> solution through a variety of complemental services. Each service offers an Application Programming Interface (API) that facilitates this integration.

This guide covers step-by-step deployment of the following major OpenStack services using a functional example architecture suitable for new users of OpenStack with sufficient Linux experience:

OpenStack services

Service	Project name	Description
Dashboard	Horizon	Provides a web-based self-service portal to interact with underlying OpenStack services, such as launching an instance, assigning IP addresses and configuring access controls.
Compute	Nova	Manages the lifecycle of compute instances in an OpenStack environment. Responsibilities include spawning, scheduling and decommissioning of virtual machines on demand.
Networking	Neutron	Enables Network-Connectivity-as-a-Service for other OpenStack services, such as OpenStack Compute. Provides an API for users to define networks and the attachments into them. Has a pluggable architecture that supports many popular networking vendors and technologies.
Storage
Object Storage	Swift	Stores and retrieves arbitrary unstructured data objects via a RESTful, HTTP based API. It is highly fault tolerant with its data replication and scale-out architecture. Its implementation is not like a file server with mountable directories. In this case, it writes objects and files to multiple drives, ensuring the data is replicated across a server cluster.
Block Storage	Cinder	Provides persistent block storage to running instances. Its pluggable driver architecture facilitates the creation and management of block storage devices.
Shared services
Identity service	Keystone	Provides an authentication and authorization service for other OpenStack services. Provides a catalog of endpoints for all OpenStack services.
Image service	Glance	Stores and retrieves virtual machine disk images. OpenStack Compute makes use of this during instance provisioning.
Telemetry	Ceilometer	Monitors and meters the OpenStack cloud for billing, benchmarking, scalability, and statistical purposes.
Higher-level services
Orchestration	Heat	Orchestrates multiple composite cloud applications by using either the native HOT <Heat Orchestration Template (HOT)> template format or the AWS CloudFormation template format, through both an OpenStack-native REST API and a CloudFormation-compatible Query API.

After becoming familiar with basic installation, configuration, operation, and troubleshooting of these OpenStack services, you should consider the following steps toward deployment using a production architecture:

• Determine and implement the necessary core and optional services to meet performance and redundancy requirements.
• Increase security using methods such as firewalls, encryption, and service policies.
• Implement a deployment tool such as Ansible, Chef, Puppet, or Salt to automate deployment and management of the production environment.

Example architecture

The example architecture requires at least two nodes (hosts) to launch a basic virtual machine <virtual machine (VM)> or instance. Optional services such as Block Storage and Object Storage require additional nodes.

This example architecture differs from a minimal production architecture as follows:

• Networking agents reside on the controller node instead of one or more dedicated network nodes.
• Overlay (tunnel) traffic for self-service networks traverses the management network instead of a dedicated network.

For more information on production architectures, see the Architecture Design Guide, OpenStack Operations Guide, and OpenStack Networking Guide.

Hardware requirements

Controller

The controller node runs the Identity service, Image service, management portions of Compute, management portion of Networking, various Networking agents, and the dashboard. It also includes supporting services such as an SQL database, message queue, and NTP.

Optionally, the controller node runs portions of Block Storage, Object Storage, Orchestration, and Telemetry services.

The controller node requires a minimum of two network interfaces.

Compute

The compute node runs the hypervisor portion of Compute that operates instances. By default, Compute uses the KVM <kernel-based VM (KVM)> hypervisor. The compute node also runs a Networking service agent that connects instances to virtual networks and provides firewalling services to instances via security groups <security group>.

You can deploy more than one compute node. Each node requires a minimum of two network interfaces.

Block Storage

The optional Block Storage node contains the disks that the Block Storage and Shared File System services provision for instances.

For simplicity, service traffic between compute nodes and this node uses the management network. Production environments should implement a separate storage network to increase performance and security.

You can deploy more than one block storage node. Each node requires a minimum of one network interface.

Object Storage

The optional Object Storage node contain the disks that the Object Storage service uses for storing accounts, containers, and objects.

For simplicity, service traffic between compute nodes and this node uses the management network. Production environments should implement a separate storage network to increase performance and security.

This service requires two nodes. Each node requires a minimum of one network interface. You can deploy more than two object storage nodes.

Networking

Choose one of the following virtual networking options.

Networking Option 1: Provider networks

The provider networks option deploys the OpenStack Networking service in the simplest way possible with primarily layer-2 (bridging/switching) services and VLAN segmentation of networks. Essentially, it bridges virtual networks to physical networks and relies on physical network infrastructure for layer-3 (routing) services. Additionally, a DHCP service provides IP address information to instances.

Note

This option lacks support for self-service (private) networks, layer-3 (routing) services, and advanced services such as LBaaS and FWaaS. Consider the self-service networks option if you desire these features.

Networking Option 2: Self-service networks

The self-service networks option augments the provider networks option with layer-3 (routing) services that enable self-service networks using overlay segmentation methods such as VXLAN. Essentially, it routes virtual networks to physical networks using NAT. Additionally, this option provides the foundation for advanced services such as LBaaS and FWaaS.