Add documentation for Volume-backed image feature

In Liberty release of Cinder, quick volume creation from Volume-backed
image is supported, and some options are added for it. This describes
the new options and how to use the feature.

Change-Id: Ic581b27ba5ab26938cacd90964081f0bce856501
Closes-Bug: #1488739
This commit is contained in:
Tomoki Sekiyama
2015-09-28 17:05:46 -04:00
parent dd2f1cc582
commit 5bf0f5bc77
2 changed files with 73 additions and 0 deletions

View File

@@ -70,4 +70,5 @@ troubleshoot your installation and back up your Compute volumes.
blockstorage_ratelimit_volume_copy_bandwidth.rst
blockstorage_over_subscription.rst
blockstorage_image_volume_cache.rst
blockstorage_volume_backed_image.rst
blockstorage_get_capabilities.rst

View File

@@ -0,0 +1,72 @@
.. _volume_backed_image:
===================
Volume-backed image
===================
OpenStack Block Storage can quickly create a volume from an image that refers
to a volume storing image data (Image-Volume). Compared to the other stores
such as file and swift, creating a volume from a Volume-backed image performs
better when the block storage driver supports efficient volume cloning.
If the image is set to public in the Image service, the volume data can be
shared among tenants.
Configure the Volume-backed image
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Volume-backed image feature requires locations information from the cinder
store of the Image service. To enable the Image service to use the cinder
store, add ``cinder`` to the ``stores`` option in the ``glance_store`` section
of the :file:`glance-api.conf` file::
stores = file, http, swift, cinder
To expose locations information, set the following options in the ``DEFAULT``
section of the :file:`glance-api.conf` file::
show_multiple_locations = True
To enable the Block Storage services to create a new volume by cloning Image-
Volume, set the following options in the ``DEFAULT`` section of the
:file:`cinder.conf` file. For example::
glance_api_version = 2
allowed_direct_url_schemes = cinder
To enable the :command:`cinder upload-to-image` command to create an image
that refers an Image-Volume, set the following options in each back-end
section of the :file:`cinder.conf` file::
image_upload_use_cinder_backend = True
By default, the :command:`upload-to-image` command creates the Image-Volume in
the current tenant. To store the Image-Volume into the internal tenant, set the
following options in each back-end section of the :file:`cinder.conf` file::
image_upload_use_internal_tenant = True
Creating a Volume-backed image
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
To register an existing volume as a new Volume-backed image, use the following
commands::
$ glance image-create --disk-format raw --container-format bare --name <name>
$ glance location-add <image-uuid> --url cinder://<volume-uuid>
If the ``image_upload_use_cinder_backend`` option is enabled, the following
command creates a new Image-Volume by cloning the specified volume and then
registers its location to a new image. The disk format and the container format
must be raw and bare (default). Otherwise, the image is uploaded to the default
store of the Image service.::
$ cinder upload-to-image <volume> <image-name>
.. note::
Currently, the cinder store of the Image services does not support uploading
and downloading of image data. By this limitation, Volume-backed images can
only be used to create a new volume.