51 lines
2.5 KiB
XML
51 lines
2.5 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="image-service-overview">
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<title>OpenStack Image Service</title>
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<para>The OpenStack Image Service is central to Infrastructure-as-a-Service (IaaS)
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as shown in <xref linkend="conceptual-architecture"/>. It accepts API requests
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for disk or server images, and image metadata from end users or OpenStack Compute
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components. It also supports the storage of disk or server images on various
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repository types, including OpenStack Object Storage.
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</para>
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<para>A number of periodic processes run on the OpenStack Image Service to
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support caching. Replication services ensure consistency and
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availability through the cluster. Other periodic processes
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include auditors, updaters, and reapers.</para>
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<para>The OpenStack Image Service includes the following
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components:</para>
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<variablelist>
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<varlistentry>
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<term><systemitem class="service">glance-api</systemitem></term>
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<listitem><para>Accepts Image API calls for image discovery,
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retrieval, and storage.</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><systemitem class="service">glance-registry</systemitem></term>
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<listitem><para>Stores, processes, and retrieves metadata about
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images. Metadata includes items such as size and type.</para>
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<note><title>Security note</title>
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<para>The registry is a private internal service meant for use
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by OpenStack Image Service. Do not disclose it to
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users.</para></note>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>Database</term>
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<listitem><para>Stores image metadata and you can choose your database
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depending on your preference. Most deployments use MySQL or
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SQLite.</para></listitem>
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</varlistentry>
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<varlistentry>
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<term>Storage repository for image files</term>
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<listitem><para>Various repository types are supported including
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normal file systems, Object Storage, RADOS block devices, HTTP, and
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Amazon S3. Note that some repositories will only support
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read-only usage.</para></listitem>
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</varlistentry>
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</variablelist>
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</section>
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