4e6fe7a6da
Kolla-Ansible Ceph deployment mechanism has been deprecated in Train [1]. This change removes the Ansible code and associated CI jobs. [1]: https://review.opendev.org/669214 Change-Id: Ie2167f02ad2f525d3b0f553e2c047516acf55bc2
149 lines
3.6 KiB
ReStructuredText
149 lines
3.6 KiB
ReStructuredText
.. _glance-guide:
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======================
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Glance - Image service
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======================
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Glance backends
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---------------
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Overview
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~~~~~~~~
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Glance can be deployed using Kolla and supports the following
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backends:
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* file
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* ceph
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* vmware
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* swift
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File backend
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~~~~~~~~~~~~
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When using the ``file`` backend, images will be stored locally
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under the value of the ``glance_file_datadir_volume`` variable, which defaults
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to a docker volume called ``glance``. By default when using ``file`` backend
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only one ``glance-api`` container can be running.
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For better reliability and performance, ``glance_file_datadir_volume`` should
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be mounted under a shared filesystem such as NFS.
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Usage of glance file backend under shared filesystem:
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.. code-block:: yaml
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glance_backend_file: "yes"
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glance_file_datadir_volume: "/path/to/shared/storage/"
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Ceph backend
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~~~~~~~~~~~~
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To make use of ``ceph`` backend in glance, simply enable external ceph.
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By default will enable backend ceph automatically.
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Please refer to :doc:`../storage/external-ceph-guide`
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on how to configure this backend.
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To enable the ceph backend manually:
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.. code-block:: yaml
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glance_backend_ceph: "yes"
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VMware backend
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~~~~~~~~~~~~~~
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To make use of VMware datastores as a glance backend,
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enable `glance_backend_vmware` and refer to :doc:`../compute/vmware-guide` for
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further VMware configuration.
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To enable the vmware backend manually:
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.. code-block:: yaml
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glance_backend_vmware: "yes"
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Swift backend
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~~~~~~~~~~~~~
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To store glance images in a swift cluster, the ``swift`` backend should
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be enabled. Refer to :doc:`../storage/swift-guide` on how to configure
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swift in kolla.
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If ceph is enabled, will have higher precedence over swift as glance backend.
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To enable the swift backend manually:
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.. code-block:: yaml
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glance_backend_swift: "yes"
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Upgrading glance
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----------------
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Overview
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~~~~~~~~
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Glance can be upgraded with the following methods:
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* Rolling upgrade
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* Legacy upgrade
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Rolling upgrade
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~~~~~~~~~~~~~~~
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As of the Rocky release, glance can be upgraded in a rolling upgrade mode.
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This mode will reduce the API downtime during upgrade to a minimum of
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a container restart, aiming for zero downtime in future releases.
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By default it is disabled, so if you want to upgrade using this mode it will
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need to be enabled.
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.. code-block:: yaml
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glance_enable_rolling_upgrade: "yes"
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.. warning::
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When using glance backend ``file`` without a shared filesystem, this method cannot
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be used or will end up with a corrupt state of glance services.
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Reasoning behind is because glance api is only running in one host, blocking the
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orchestration of a rolling upgrade.
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Legacy upgrade
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~~~~~~~~~~~~~~
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This upgrade method will stop APIs during database schema migrations,
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and container restarts.
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It is the default mode, ensure rolling upgrade method is not enabled.
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.. code-block:: yaml
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glance_enable_rolling_upgrade: "no"
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Other configuration
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-------------------
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Glance cache
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~~~~~~~~~~~~
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Glance cache is disabled by default, it can be enabled by:
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.. code-block:: yaml
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enable_glance_image_cache: "yes"
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glance_cache_max_size: "10737418240" # 10GB by default
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.. warning::
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When using the ceph backend, is recommended to not use glance cache, since
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nova already has a cached version of the image, and the image is directly
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copied from ceph instead of glance api hosts. Enabling glance cache will
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lead to unnecessary storage consumption.
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Glance caches are not cleaned up automatically, the glance team recommends to
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use a cron service to regularly clean cached images. In the future kolla will
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deploy a cron container to manage such clean ups. Please refer to
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:glance-doc:`Glance image cache <admin/cache.html>`.
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