dd1671a7bb
Updates: - Removed references to the S3 backend, whose driver was removed with change I032b0fc16400cbd2112687d38e010128be699221 - Clarified use of filesystem store, based on an actual question asked in #openstack-glance - Expanded the list of backends mentioned where appropriate Change-Id: Ic0220a714beadd54cdf0c86ce65ab9223a88a3de
48 lines
1.9 KiB
ReStructuredText
48 lines
1.9 KiB
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======================
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Image service overview
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======================
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The OpenStack Image service is central to Infrastructure-as-a-Service
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(IaaS) as shown in :ref:`get_started_conceptual_architecture`. It accepts API
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requests for disk or server images, and metadata definitions from end users or
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OpenStack Compute components. It also supports the storage of disk or server
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images on various repository types, including OpenStack Object Storage.
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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 include
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auditors, updaters, and reapers.
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The OpenStack Image service includes the following components:
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glance-api
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Accepts Image API calls for image discovery, retrieval, and storage.
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glance-registry
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Stores, processes, and retrieves metadata about images. Metadata
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includes items such as size and type.
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.. warning::
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The registry is a private internal service meant for use by
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OpenStack Image service. Do not expose this service to users.
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Database
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Stores image metadata and you can choose your database depending on
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your preference. Most deployments use MySQL or SQLite.
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Storage repository for image files
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Various repository types are supported including normal file
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systems (or any filesystem mounted on the glance-api controller
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node), Object Storage, RADOS block devices, VMware datastore,
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and HTTP. Note that some repositories will only support read-only
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usage.
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Metadata definition service
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A common API for vendors, admins, services, and users to meaningfully
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define their own custom metadata. This metadata can be used on
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different types of resources like images, artifacts, volumes,
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flavors, and aggregates. A definition includes the new property's key,
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description, constraints, and the resource types which it can be
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associated with.
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