OpenStack is a free and open-source cloud computing software platform.[2] Users primarily deploy it as an infrastructure as a service (IaaS) solution. The technology consists of a series of interrelated projects that control pools of processing, storage, and networking resources throughout a data center—which users manage through a web-based dashboard, command-line tools, or a RESTful API. released it under the terms of the Apache License.

OpenStack began in 2010 as a joint project of Rackspace Hosting and NASA. Currently, it is managed by the OpenStack Foundation, a non-profit corporate entity established in September 2012[3] to promote OpenStack software and its community.[4] More than 200 companies have joined the project, including Arista Networks, AT&T, AMD, Avaya, Canonical, Cisco, Dell, EMC, Ericsson, Go Daddy, Hewlett-Packard, Huawei, IBM, Intel, Mellanox, Mirantis, NEC, NetApp, Nexenta, Oracle, PLUMgrid, Pure Storage, Red Hat, SolidFire, SUSE Linux, VMware and Yahoo!.[5][6][7][8][9][10][11]

The OpenStack community collaborates around a six-month, time-based release cycle with frequent development milestones.[12] During the planning phase of each release, the community gathers for the OpenStack Design Summit to facilitate developer working-sessions and to assemble plans.[13]

The most recent OpenStack Summit was held in Paris in November 2014.[14] The previous summit in May 2014 in Atlanta, drew 4,500 attendees, a 50% increase from the Hong Kong Summit six months earlier.[15][16]


OpenStack has a modular architecture with various code names for its components.[25]

Compute (Nova)

OpenStack Compute (Nova) is a cloud computing fabric controller, which is the main part of an IaaS system. It is designed to manage and automate pools of computer resources and can work with widely available virtualization technologies, as well as bare metal and high-performance computing (HPC) configurations. KVM, VMware, and Xen are available choices for hypervisor technology, together with Hyper-V and Linux container technology such as LXC.[26][27]

It is written in Python and uses many external libraries such as Eventlet (for concurrent programming), Kombu (for AMQP communication), and SQLAlchemy (for database access).[28] Compute’s architecture is designed to scale horizontally on standard hardware with no proprietary hardware or software requirements and provide the ability to integrate with legacy systems and third-party technologies.

Object Storage (Swift)

OpenStack Object Storage (Swift) is a scalable redundant storage system. Objects and files are written to multiple disk drives spread throughout servers in the data center, with the OpenStack software responsible for ensuring data replication and integrity across the cluster. Storage clusters scale horizontally simply by adding new servers. Should a server or hard drive fail, OpenStack replicates its content from other active nodes to new locations in the cluster. Because OpenStack uses software logic to ensure data replication and distribution across different devices, inexpensive commodity hard drives and servers can be used.

In August 2009, Rackspace started the development of the precursor to OpenStack Object Storage, as a complete replacement for the Cloud Files product. The initial development team consisted of nine developers.[29] SwiftStack, an object storage software company, is currently the leading developer for Swift.[citation

Block Storage (Cinder)

OpenStack Block Storage (Cinder) provides persistent block-level storage devices for use with OpenStack compute instances. The block storage system manages the creation, attaching and detaching of the block devices to servers. Block storage volumes are fully integrated into OpenStack Compute and the Dashboard allowing for cloud users to manage their own storage needs. In addition to local Linux server storage, it can use storage platforms including Ceph, CloudByte, Coraid, EMC (ScaleIO, VMAX and VNX), GlusterFS, Hitachi Data Systems, IBM Storage (Storwize family, SAN Volume Controller, XIV Storage System, and GPFS), Linux LIO, NetApp, Nexenta, Scality, SolidFire, HP (StoreVirtual and 3PAR StoreServ families) and Pure Storage. Block storage is appropriate for performance sensitive scenarios such as database storage, expandable file systems, or providing a server with access to raw block level storage. Snapshot management provides powerful functionality for backing up data stored on block storage volumes. Snapshots can be restored or used to create a new block storage volume.

Networking (Neutron)

OpenStack Networking (Neutron, formerly Quantum[30]) is a system for managing networks and IP addresses. OpenStack Networking ensures the network is not a bottleneck or limiting factor in a cloud deployment, and gives users self-service ability, even over network configurations.

OpenStack Networking provides networking models for different applications or user groups. Standard models include flat networks or VLANs that separate servers and traffic. OpenStack Networking manages IP addresses, allowing for dedicated static IP addresses or DHCP. Floating IP addresses let traffic be dynamically rerouted to any resources in the IT infrastructure, so users can redirect traffic during maintenance or in case of a failure.

Users can create their own networks, control traffic, and connect servers and devices to one or more networks. Administrators can use software-defined networking (SDN) technology like OpenFlow to support high levels of multi-tenancy and massive scale. OpenStack Networking provides an extension framework that can deploy and manage additional network services—such as intrusion detection systems (IDS), load balancing, firewalls, and virtual private networks (VPN).

Dashboard (Horizon)

OpenStack Dashboard (Horizon) provides administrators and users a graphical interface to access, provision, and automate cloud-based resources. The design accommodates third party products and services, such as billing, monitoring, and additional management tools. The dashboard is also brandable for service providers and other commercial vendors who want to make use of it. The dashboard is one of several ways users can interact with OpenStack resources. Developers can automate access or build tools to manage resources using the native OpenStack API or the EC2 compatibility API.

Identity Service (Keystone)

OpenStack Identity (Keystone) provides a central directory of users mapped to the OpenStack services they can access. It acts as a common authentication system across the cloud operating system and can integrate with existing backend directory services like LDAP. It supports multiple forms of authentication including standard username and password credentials, token-based systems and AWS-style (i.e. Amazon Web Services) logins. Additionally, the catalog provides a queryable list of all of the services deployed in an OpenStack cloud in a single registry. Users and third-party tools can programmatically determine which resources they can access.

Image Service (Glance)

OpenStack Image Service (Glance) provides discovery, registration, and delivery services for disk and server images. Stored images can be used as a template. It can also be used to store and catalog an unlimited number of backups. The Image Service can store disk and server images in a variety of back-ends, including OpenStack Object Storage. The Image Service API provides a standard REST interface for querying information about disk images and lets clients stream the images to new servers. updates Glance every six months, along with other OpenStack modules. Some of the updates are to catch-up with existing cloud infrastructure services, as OpenStack is comparatively new. Glance adds many enhancements to existing legacy infrastructures. For example, if integrated with VMware, Glance introduces advanced features to the vSphere family such as, vMotion, high availability and dynamic resource scheduling (DRS). vMotion is the live migration of a running VM, from one physical server to another, without service interruption. Thus, it enables a dynamic and automated self-optimizing datacenter, allowing hardware maintenance for the underperforming servers without downtimes.[31][32]

OpenStack’s image is an operating system installed on a virtual machine (VM). If a developer adds a variation to an image (as a configuration job) the result is an instance of that image. Subsequently, that instance is an image that developers can add more variations to.

Glance—OpenStack’s image service module—is a compute module, as it does not store images, variations, or instances—but rather catalogs them and holds their metadata from Swift or a storage backend datastore. Other modules must communicate with the images metadata through Glance—or example, Heat. Also, Nova can present information about the images, and configure a variation on an image to produce an instance. However, Glance is the only module that can add, delete, share, or duplicate images.[33]

Telemetry (Ceilometer)

OpenStack Telemetry Service (Ceilometer) provides a Single Point Of Contact for billing systems, providing all the counters they need to establish customer billing, across all current and future OpenStack components. The delivery of counters is traceable and auditable, the counters must be easily extensible to support new projects, and agents doing data collections should be independent of the overall system.

Orchestration (Heat)

Heat is a service to orchestrate multiple composite cloud applications using templates, through both an OpenStack-native REST API and a CloudFormation-compatible Query API.[34]

Database (Trove)

Trove is a database-as-a-service provisioning relational and non-relational database engines.[35]

Bare Metal Provisioning (Ironic)

Ironic is an incubated OpenStack project that aims to provision bare metal machines instead of virtual machines. It was initially forked from the Nova Baremetal driver and has evolved into a separate program. It is best thought of as a bare-metal hypervisor API and a set of plugins that interact with the bare-metal hypervisors. By default, it will use PXE and IPMI in concert to provision and turn on and off machines, but Ironic supports and can be extended with vendor-specific plugins to implement additional functionality.[36][37]

Multiple Tenant Cloud Messaging (Zaqar)

Zaqar is a multi-tenant cloud messaging service for Web developers. It combines the ideas pioneered by Amazon’s SQS product with additional semantics to support event broadcasting. The service features a fully RESTful API, which developers can use to send messages between various components of their SaaS and mobile applications by using a variety of communication patterns. Underlying this API is an efficient messaging engine designed with scalability and security in mind. Other OpenStack components can integrate with Zaqar to surface events to end users and to communicate with guest agents that run in the "over-cloud" layer. Cloud operators can leverage Zaqar to provide equivalents of SQS and SNS to their customers. Zaqar was formerly known as Marconi.[38][39]

Elastic Map Reduce (Sahara)

Sahara aims to provide users with simple means to provision Hadoop clusters by specifying several parameters like Hadoop version, cluster topology, nodes hardware details and a few more. After a user fills all the parameters, Sahara deploys the cluster in a few minutes. Sahara also provides means to scale already provisioned cluster by adding and removing worker nodes on demand.[40][41]

Amazon Web Services compatibility

OpenStack APIs are compatible with Amazon EC2 and Amazon S3 and thus client applications written for Amazon Web Services can be used with OpenStack with minimal porting effort.[42][43]


OpenStack has a wide variety of users, from a number of different sectors.[49] Notable users include:

Release history

Release name Release date Included Component code names[25] Notes
Austin 21 October 2010[66][67] Nova, Swift Austin Release Notes
Bexar 3 February 2011[68] Nova, Glance, Swift Bexar Release Notes
Cactus 15 April 2011[69] Nova, Glance, Swift Cactus Release Notes
Diablo 22 September 2011[70] Nova, Glance, Swift Diablo Release Notes
Essex 5 April 2012[71] Nova, Glance, Swift, Horizon, Keystone Essex Release Notes
Folsom 27 September 2012[72] Nova, Glance, Swift, Horizon, Keystone, Quantum, Cinder Folsom Release Notes
Grizzly 4 April 2013[73] Nova, Glance, Swift, Horizon, Keystone, Quantum, Cinder Grizzly Release Notes
Havana 17 October 2013[74] Nova, Glance, Swift, Horizon, Keystone, Neutron, Cinder, Heat, Ceilometer Havana Release Notes
Icehouse 17 April 2014[75] Nova, Glance, Swift, Horizon, Keystone, Neutron, Cinder, Heat, Ceilometer, Trove Icehouse Release Notes
Juno 16 October 2014[76] Nova, Glance, Swift, Horizon, Keystone, Neutron, Cinder, Heat, Ceilometer, Trove, Sahara Juno Release Notes
Kilo April 2015[77] Nova, Glance, Swift, Horizon, Keystone, Neutron, Cinder, Heat, Ceilometer, Trove, Sahara, Ironic, Zaqar, Manila, Designate, Barbican Not yet released