openstack-manuals/doc/common/section_getstart_architecture.xml

<section xmlns="http://docbook.org/ns/docbook"
    xmlns:xi="http://www.w3.org/2001/XInclude"
    xmlns:xlink="http://www.w3.org/1999/xlink" version="5.0"
    xml:id="openstack-architecture">
    <title>OpenStack architecture</title>
    <para>The following table describes the OpenStack services that
      make up the OpenStack architecture. You may only install some
      of these, depending on your needs.</para>
    <table rules="all">
      <caption>OpenStack services</caption>
      <col width="20%"/>
      <col width="10%"/>
      <col width="70%"/>
      <thead>
        <tr>
          <th>Service</th>
          <th>Project name</th>
          <th>Description</th>
        </tr>
      </thead>
      <tbody>
        <tr>
          <td><link
              xlink:href="http://www.openstack.org/software/openstack-dashboard/"
              >Dashboard</link></td>
          <td><link
              xlink:href="http://docs.openstack.org/developer/horizon/"
              >Horizon</link></td>
          <td>Enables users to interact with all OpenStack services to
            launch an instance, assign IP addresses, set access
            controls, and so on.</td>
        </tr>
        <tr>
          <td><link
              xlink:href="http://www.openstack.org/software/openstack-shared-services/"
              >Identity Service</link></td>
          <td><link
              xlink:href="http://docs.openstack.org/developer/keystone/"
              >Keystone</link></td>
          <td>Provides authentication and authorization for all the
            OpenStack services. Also provides a service catalog within
            a particular OpenStack cloud.</td>
        </tr>
        <tr>
          <td><link
              xlink:href="http://www.openstack.org/software/openstack-compute/"
              >Compute Service</link></td>
          <td><link
              xlink:href="http://docs.openstack.org/developer/nova/"
              >Nova</link></td>
          <td>Provisions and manages large networks of virtual
            machines on demand.</td>
        </tr>
        <tr>
          <td><link
              xlink:href="http://www.openstack.org/software/openstack-storage/"
              >Object Storage Service</link></td>
          <td><link
              xlink:href="http://docs.openstack.org/developer/swift/"
              >Swift</link></td>
          <td>Stores and retrieves files. Does not mount directories
            like a file server.</td>
        </tr>
        <tr>
          <td><link
              xlink:href="http://www.openstack.org/software/openstack-storage/"
              >Block Storage Service</link></td>
          <td><link
              xlink:href="http://docs.openstack.org/developer/cinder/"
              >Cinder</link></td>
          <td>Provides persistent block storage to guest virtual
            machines.</td>
        </tr>
        <tr>
          <td><link
              xlink:href="http://www.openstack.org/software/openstack-shared-services/"
              >Image Service</link></td>
          <td><link
              xlink:href="http://docs.openstack.org/developer/glance/"
              >Glance</link></td>
          <td>Provides a registry of virtual machine images. Compute
            Service uses it to provision instances.</td>
        </tr>
        <tr>
          <td><link
              xlink:href="http://www.openstack.org/software/openstack-networking/"
              >Networking Service</link></td>
          <td><link
              xlink:href="http://docs.openstack.org/developer/neutron/"
              >Neutron</link></td>
          <td>Enables network connectivity as a service among
            interface devices managed by other OpenStack services,
            usually Compute Service. Enables users to create and
            attach interfaces to networks. Has a pluggable
            architecture that supports many popular networking vendors
            and technologies.</td>
        </tr>
        <tr>
          <td><link
              xlink:href="http://www.openstack.org/software/openstack-shared-services/"
              >Metering/Monitoring Service</link></td>
          <td><link
              xlink:href="http://docs.openstack.org/developer/ceilometer/"
              >Ceilometer</link></td>
          <td>Monitors and meters the OpenStack cloud for billing,
            benchmarking, scalability, and statistics purposes.</td>
        </tr>
        <tr>
          <td><link
              xlink:href="http://www.openstack.org/software/openstack-shared-services/"
              >Orchestration Service</link></td>
          <td><link
              xlink:href="http://docs.openstack.org/developer/heat/"
              >Heat</link></td>
          <td>Orchestrates multiple composite cloud applications by
            using the AWS CloudFormation template format, through both
            an OpenStack-native REST API and a
            CloudFormation-compatible Query API.</td>
        </tr>
      </tbody>
    </table>
    <?hard-pagebreak?>
    <section xml:id="conceptual-architecture">
      <title>Conceptual architecture</title>
      <para>The following diagram shows the relationships among the
        OpenStack services:</para>
      <informalfigure xml:id="concept_arch">
        <mediaobject>
          <imageobject>
            <imagedata
              fileref="figures/openstack_havana_conceptual_arch.png"
              contentwidth="6in"/>
          </imageobject>
        </mediaobject>
      </informalfigure>
    </section>
    <?hard-pagebreak?>
    <section xml:id="logical-architecture">
      <title>Logical architecture</title>
      <para>To design, install, and configure a cloud, cloud
        administrators must understand the logical
        architecture.</para>
      <para>OpenStack modules are one of the following types:</para>
      <itemizedlist>
        <listitem>
          <para>Daemon. Runs as a daemon. On Linux platforms, are
            usually installed as a service.</para>
        </listitem>
        <listitem>
          <para>Script. Runs installation and tests of a virtual
            environment. For example, a script called
              <code>run_tests.sh</code> installs a virtual environment
            for a service and then may also run tests to verify that
            virtual environment functions well.</para>
        </listitem>
        <listitem>
          <para>Command-line interface (CLI). Enables users to submit
            API calls to OpenStack services through easy-to-use
            commands.</para>
        </listitem>
      </itemizedlist>
      <para>The following diagram shows the most common, but not the
        only, architecture for an OpenStack cloud:</para>
      <!-- Source files in this repository in doc/src/docbkx/common/figures/openstack-arch-grizzly-v1.zip https://github.com/openstack/openstack-manuals/raw/master/doc/src/docbkx/common/figures/openstack-arch-grizzly-v1.zip -->
      <figure xml:id="os-logical-arch">
        <title>OpenStack logical architecture</title>
        <mediaobject>
          <imageobject>
            <imagedata
              fileref="figures/openstack-arch-grizzly-v1-logical.jpg"
              contentwidth="6.5in"/>
          </imageobject>
        </mediaobject>
      </figure>
      <para>As in the conceptual architecture, end users can interact
        through the dashboard, CLIs, and APIs. All services
        authenticate through a common Identity Service and individual
        services interact with each other through public APIs, except
        where privileged administrator commands are necessary.</para>
    </section>
</section>