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[Walt Boring <walter.boring@xxxxxxx>]

Public bug reported:

The Nova API shouldn't be looking at the internal state of a Cinder
volume to determine if it can attach.  It should simply ask Cinder to
reserve the volume.  Cinder already has checks during reserve time for
checking states.

Nova currently fetches a volume from Cinder, then checks to see if the state of the volume is in an appropriate state to attach, and then calls reserve.  The problem is 2 fold.
1) Nova shouldn't care about the internal state management of Cinder Volumes.  What happens if Cinder adds a new state that Nova doesn't know about?
2) By fetching a volume and checking, and then reserving, there is a race condition introduced.  The state of the volume can change between the time the volume is fetched from Cinder and when reserve is called.

Nova should simply call reserve volume.

** Affects: nova
     Importance: Undecided
     Assignee: Walt Boring (walter-boring)
         Status: New

** Changed in: nova
     Assignee: (unassigned) => Walt Boring (walter-boring)

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https://bugs.launchpad.net/bugs/1581230

Title:
  Nova should not inspect cinder volume state during attach

Status in OpenStack Compute (nova):
  New

Bug description:
  The Nova API shouldn't be looking at the internal state of a Cinder
  volume to determine if it can attach.  It should simply ask Cinder to
  reserve the volume.  Cinder already has checks during reserve time for
  checking states.

  Nova currently fetches a volume from Cinder, then checks to see if the state of the volume is in an appropriate state to attach, and then calls reserve.  The problem is 2 fold.
  1) Nova shouldn't care about the internal state management of Cinder Volumes.  What happens if Cinder adds a new state that Nova doesn't know about?
  2) By fetching a volume and checking, and then reserving, there is a race condition introduced.  The state of the volume can change between the time the volume is fetched from Cinder and when reserve is called.

  Nova should simply call reserve volume.

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