fe21b1d19f
Updates scrubber docs to take into account the refactoring done in change I26f570b85617200880543b7114730a1ac76d3fb1 and updates the header info for all cli docs in anticipation of the Queens release. Change-Id: I61095b9ba8f7e12fcf2005aa6f8af501829dfa6b
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4.6 KiB
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119 lines
4.6 KiB
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===============
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glance-scrubber
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===============
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--------------------
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Glance scrub service
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--------------------
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.. include:: header.txt
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SYNOPSIS
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========
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glance-scrubber [options]
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DESCRIPTION
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===========
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glance-scrubber is a utility that allows an operator to configure Glance for
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the asynchronous deletion of images. Whether this makes sense for your
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deployment depends upon the storage backend you are using and the size of
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typical images handled by your Glance installation.
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An image in glance is really a combination of an image record (stored in the
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database) and a file of image data (stored in a storage backend). Under normal
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operation, the image-delete call is synchronous, that is, Glance receives the
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DELETE request, deletes the image data from the storage backend, then deletes
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the image record from the database, and finally returns a 204 as the result of
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the call. If the backend is fast and deletion time is not a function of data
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size, these operations occur very quickly. For backends where deletion time is
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a function of data size, however, the image-delete operation can take a
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significant amount of time to complete, to the point where a client may timeout
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waiting for the response. This in turn leads to user dissatisfaction.
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To avoid this problem, Glance has a ``delayed_delete`` configuration option
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(False by default) that may be set in the **glance-api.conf** file. With this
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option enabled, when Glance receives a DELETE request, it does *only* the
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database part of the request, marking the image's status as ``pending_delete``,
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and returns immediately. (The ``pending_delete`` status is not visible to
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users; an image-show request for such an image will return 404.) However, it
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is important to note that when ``delayed_delete`` is enabled, *Glance does not
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delete image data from the storage backend*. That's where the glance-scrubber
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comes in.
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The glance-scrubber cleans up images that have been deleted. If you run Glance
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with ``delayed_delete`` enabled, you *must* run the glance-scrubber
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occasionally or your storage backend will eventually fill up with "deleted"
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image data.
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Configuration of glance-scrubber is done in the **glance-scrubber.conf** file.
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Options are explained in detail in comments in the sample configuration file,
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so we only point out a few of them here.
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``scrub_time``
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minimum time in seconds that an image will stay in ``pending_delete``
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status (default is 0)
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``scrub_pool_size``
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configures a thread pool so that scrubbing can be performed in parallel
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(default is 1, that is, serial scrubbing)
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``daemon``
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a boolean indicating whether the scrubber should run as a daemon
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(default is False)
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``wakeup_time``
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time in seconds between runs when the scrubber is run in daemon mode
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(ignored if the scrubber is not being run in daemon mode)
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``metadata_encryption_key``
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If your **glance-api.conf** sets a value for this option (the default is to
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leave it unset), you must include the same setting in your
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**glance-scrubber.conf** or the scrubber won't be able to determine the
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locations of your image data.
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``[database]``
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As of the Queens release of Glance (16.0.0), the glance-scrubber does not
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use the deprecated Glance registry, but instead contacts the Glance
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database directly. Thus your **glance-scrubber.conf** file must contain a
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[database] section specifying the relevant information.
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``[glance_store]``
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This section of the file contains the configuration information for the
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storage backends used by your Glance installation.
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The usual situation is that whatever your **glance-api.conf** has for the
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``[database]`` and ``[glance_store]`` configuration groups should go into your
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**glance-scrubber.conf**, too. Of course, if you have heavily customized your
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setup, you know better than we do what you are doing. The key thing is that
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the scrubber needs to be able to access the Glance database to determine what
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images need to be scrubbed (and to mark them as deleted once their associated
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data has been removed from the storage backend), and it needs the glance_store
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information so it can delete the image data.
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OPTIONS
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=======
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**General options**
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.. include:: general_options.txt
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**-D, --daemon**
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Run as a long-running process. When not specified (the
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default) run the scrub operation once and then exits.
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When specified do not exit and run scrub on
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wakeup_time interval as specified in the config.
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**--nodaemon**
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The inverse of --daemon. Runs the scrub operation once and
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then exits. This is the default.
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FILES
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=====
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**/etc/glance/glance-scrubber.conf**
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Default configuration file for the Glance Scrubber
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.. include:: footer.txt
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