cinder-manage object delete --db-only

Adds the option to delete objects only from DB.

Objects:
- volumes
- backups

Change-Id: I7c8bc1ec1d4c1e74c1197930fe5e5667e26bfbd5
Blueprint: cinder-delete-from-db

specs/stein/delete-from-db.rst

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+..
+ This work is licensed under a Creative Commons Attribution 3.0 Unported
+ License.
+
+ http://creativecommons.org/licenses/by/3.0/legalcode
+
+==================================================
+Object deletion from DB without driver interaction
+==================================================
+
+https://blueprints.launchpad.net/cinder/+spec/cinder-delete-from-db
+
+
+Problem description
+===================
+
+It's impossible to delete a volume, a backup or a snapshot when the service is
+not available. There's no way to bypass driver interaction.
+
+Use Cases
+=========
+
+Sometimes, OpenStack admins are pulling the plugs off some storage backends to
+use a new one. They realize later that they need to cleanup the various
+objects.
+
+
+Proposed change
+===============
+
+With cinder-manage, we will have a --db-only switch under the volume delete
+command. The snapshots are deleted in cascade. We will also implement backup
+subcommand that acts like the volume subcommand.
+
+Alternatives
+------------
+
+The only known workaround is to manually update multiple tables and set the
+status to 'deleted' to various objects.
+
+Data model impact
+-----------------
+
+None
+
+REST API impact
+---------------
+
+None
+
+Security impact
+---------------
+
+None
+
+Active/Active HA impact
+-----------------------
+
+None
+
+Notifications impact
+--------------------
+
+None
+
+Other end user impact
+---------------------
+
+These commands will be available to operators:
+
+.. code-block:: console
+
+ cinder-manage volume delete [--db-only] <volume-id>
+ cinder-manage backup delete [--db-only] <backup-id>
+
+Performance Impact
+------------------
+
+None
+
+Other deployer impact
+---------------------
+
+None
+
+Developer impact
+----------------
+
+None
+
+Implementation
+==============
+
+Assignee(s)
+-----------
+
+Primary assignee: David Vallee Delisle <dvd@redhat.com>
+
+Work Items
+----------
+
+The following changes will be done under cinder-manage command:
+* Add a --db-only switch to the volume delete command.
+* Add a backup delete subcommand with --db-only support.
+* The snapshots are deleted in cascade when a volume is deleted.
+
+The following changes will be done in the rpcapis:
+* Add a db_only argument in the delete function
+
+The following changes will be done in the manages:
+* Add a db_only argument in the delete function
+
+Dependencies
+============
+
+None
+
+Testing
+=======
+
+Create tests to validate the delete volume and the delete backup are really
+deleting.
+
+Documentation Impact
+====================
+
+Man page for cinder-manage and any associated documentation will be updated.
+
+References
+==========
+
+None