57fadeb3aa
The text on this page seems to be copied directly from a developer guide and is largely irrelevant for admins. Text must be rewritten, and the diagram, which depicts the situation at Havana time, must be redrawn. Change-Id: I8f0a9538661292619bd8375ae03d20fe3cee2b5e Closes-Bug: #1431079
53 lines
2.3 KiB
XML
53 lines
2.3 KiB
XML
<?xml version="1.0" encoding="UTF-8"?>
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<section xmlns="http://docbook.org/ns/docbook"
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xmlns:xi="http://www.w3.org/2001/XInclude"
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xmlns:xlink="http://www.w3.org/1999/xlink"
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version="5.0"
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xml:id="logical-architecture">
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<title>Logical architecture</title>
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<para>To design, deploy, and configure OpenStack, administrators must understand the logical architecture.</para>
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<para>As shown in <xref linkend="concept_arch"/>, OpenStack consists of
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several
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independent parts, named the OpenStack services.
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All services authenticate
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through a common Identity service. Individual services interact
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with each other through public APIs, except where privileged
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administrator commands are necessary.</para>
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<para>Internally, OpenStack services are composed of several processes.
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All services have at least one
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API process, which listens for API requests, preprocesses them and
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passes them on to other parts of the service. With the exception of
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the Identity service, the actual work is done by distinct processes.</para>
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<para>For communication between the processes of one service, an AMQP <glossterm>message
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broker</glossterm> is used. The service's state is stored in a database.
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When deploying and configuring your OpenStack cloud, you can choose among
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several message broker and database solutions, such as
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RabbitMQ, Qpid, MySQL, MariaDB, and SQLite.</para>
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<para>Users can access OpenStack via the web-based user interface implemented
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by the <link linkend="ch_install-dashboard">dashboard service</link>,
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via <link xlink:href="http://docs.openstack.org/cli-reference/content">command-line clients</link>
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and by issuing API requests through tools like
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browser plug-ins or <command>curl</command>. For applications,
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<link xlink:href="http://developer.openstack.org/#sdk">several SDKs</link>
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are available. Ultimately, all these access methods issue REST API
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calls to the various OpenStack services.</para>
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<para>The following diagram shows the most common, but not the only
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possible, architecture for an OpenStack cloud:</para>
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<figure xml:id="os-logical-arch">
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<title>Logical architecture</title>
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<mediaobject>
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<imageobject>
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<imagedata
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fileref="figures/openstack-arch-kilo-logical-v1.png"
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contentwidth="10in"/>
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</imageobject>
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</mediaobject>
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</figure>
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</section>
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