45 lines
2.0 KiB
XML
45 lines
2.0 KiB
XML
<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" version="5.0"
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xml:id="image-service-overview">
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<title>Image Service Overview</title>
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<para>The Image Service includes the following
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components:</para>
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<itemizedlist>
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<listitem>
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<para><systemitem class="service">glance-api</systemitem>.
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Accepts Image API calls for image discovery, retrieval,
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and storage.</para>
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</listitem>
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<listitem>
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<para><systemitem class="service"
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>glance-registry</systemitem>. Stores, processes, and
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retrieves metadata about images. Metadata includes size,
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type, and so on.</para>
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</listitem>
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<listitem>
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<para>Database. Stores image metadata. You can choose your
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database depending on your preference. Most deployments
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use MySQL or SQlite.</para>
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</listitem>
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<listitem>
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<para>Storage repository for image files. In <xref
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linkend="os-logical-arch"/>, the Object Storage Service
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is the image repository. However, you can configure a
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different repository. The Image Service supports normal
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file systems, RADOS block devices, Amazon S3, and HTTP.
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Some of these choices are limited to read-only
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usage.</para>
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</listitem>
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</itemizedlist>
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<para>A number of periodic processes run on the Image Service to
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support caching. Replication services ensures 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>As shown in <xref linkend="concept_arch"/>, the Image
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Service is central to the overall IaaS picture. It accepts API
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requests for images or image metadata from end users or
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Compute components and can store its disk files in the Object
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Storage Service.</para>
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</section>
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