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[Matt Riedemann <mriedem.os@xxxxxxxxx>]

** Changed in: nova
   Importance: Undecided => Medium

** Also affects: nova/rocky
   Importance: Undecided
       Status: New

** Also affects: nova/queens
   Importance: Undecided
       Status: New

** Also affects: nova/stein
   Importance: Undecided
       Status: New

** Changed in: nova/queens
       Status: New => In Progress

** Changed in: nova/rocky
       Status: New => In Progress

** Changed in: nova/stein
       Status: New => In Progress

** Changed in: nova/stein
   Importance: Undecided => Medium

** Changed in: nova/rocky
   Importance: Undecided => Medium

** Changed in: nova/queens
   Importance: Undecided => Medium

-- 
You received this bug notification because you are a member of Yahoo!
Engineering Team, which is subscribed to OpenStack Compute (nova).
https://bugs.launchpad.net/bugs/1803961

Title:
  Nova doesn't call migrate_volume_completion after cinder volume
  migration

Status in OpenStack Compute (nova):
  Fix Released
Status in OpenStack Compute (nova) queens series:
  In Progress
Status in OpenStack Compute (nova) rocky series:
  In Progress
Status in OpenStack Compute (nova) stein series:
  In Progress

Bug description:
  Originally reported in Red Hat Bugzilla:
  https://bugzilla.redhat.com/show_bug.cgi?id=1648931

  Create a cinder volume, attach it to a nova instance, and migrate the
  volume to a different storage host:

  $ cinder create 1 --volume-type foo --name myvol
  $ nova volume-attach myinstance myvol
  $ cinder migrate myvol c-vol2

  Everything seems to work correctly, but if we look at myinstance we
  see that it's now connected to a new volume, and the original volume
  is still present on the original storage host.

  This is because nova didn't call cinder's migrate_volume_completion.
  migrate_volume_completion would have deleted the original volume, and
  changed the volume id of the new volume to be the same as the
  original. The result would be that myinstance would appear to be
  connected to the same volume as before.

  Note that there are 2 ways (that I'm aware of) to intiate a cinder
  volume migration: retype and migrate. AFAICT retype is *not* affected.
  In fact, I updated the relevant tempest test to try to trip it up and
  it didn't fail. However, an exlicit migrate *is* affected. They are
  different top-level entry points in cinder, and set different state,
  which is what triggers the Nova bug.

  This appears to be a regression which was introduced by
  https://review.openstack.org/#/c/456971/ :

          # Yes this is a tightly-coupled state check of what's going on inside
          # cinder, but we need this while we still support old (v1/v2) and
          # new style attachments (v3.44). Once we drop support for old style
          # attachments we could think about cleaning up the cinder-initiated
          # swap volume API flows.
          is_cinder_migration = (
              True if old_volume['status'] in ('retyping',
                                               'migrating') else False)

  There's a bug here because AFAICT cinder never sets status to
  'migrating' during any operation: it sets migration_status to
  'migrating' during both retype and migrate. During retype it sets
  status to 'retyping', but not during an explicit migrate.

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