40 lines
1.7 KiB
ReStructuredText
40 lines
1.7 KiB
ReStructuredText
====================
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Logical architecture
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====================
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To design, deploy, and configure OpenStack, administrators must
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understand the logical architecture.
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As shown in :ref:`get_started_conceptual_architecture`, OpenStack consists of
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several independent parts, named the OpenStack services. All services
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authenticate through a common Identity service. Individual services interact
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with each other through public APIs, except where privileged administrator
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commands are necessary.
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Internally, OpenStack services are composed of several processes. All
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services have at least one API process, which listens for API requests,
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preprocesses them and passes them on to other parts of the service. With
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the exception of the Identity service, the actual work is done by
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distinct processes.
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For communication between the processes of one service, an AMQP message
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broker is used. The service's state is stored in a database. When
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deploying and configuring your OpenStack cloud, you can choose among
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several message broker and database solutions, such as RabbitMQ,
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MySQL, MariaDB, and SQLite.
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Users can access OpenStack via the web-based user interface implemented
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by the Horizon Dashboard, via `command-line
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clients <https://docs.openstack.org/cli-reference/>`__ and by
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issuing API requests through tools like browser plug-ins or :command:`curl`.
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For applications, `several SDKs <https://developer.openstack.org/#sdk>`__
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are available. Ultimately, all these access methods issue REST API calls
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to the various OpenStack services.
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The following diagram shows the most common, but not the only possible,
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architecture for an OpenStack cloud:
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.. image:: figures/openstack-arch-kilo-logical-v1.png
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:alt: Logical architecture
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:width: 100%
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