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On 06/19/2017 09:22 AM, Matt Riedemann wrote:
> On 6/16/2017 8:58 AM, Eric Harney wrote:
>> I'm not convinced yet that this failure is purely Ceph-specific, at a
>> quick look.
>>
>> I think what happens here is, unshelve performs an asynchronous delete
>> of a glance image, and returns as successful before the delete has
>> necessarily completed.  The check in tempest then sees that the image
>> still exists, and fails -- but this isn't valid, because the unshelve
>> API doesn't guarantee that this image is no longer there at the time it
>> returns.  This would fail on any image delete that isn't instantaneous.
>>
>> Is there a guarantee anywhere that the unshelve API behaves how this
>> tempest test expects it to?
> 
> There are no guarantees, no. The unshelve API reference is here [1]. The
> asynchronous postconditions section just says:
> 
> "After you successfully shelve a server, its status changes to ACTIVE.
> The server appears on the compute node.
> 
> The shelved image is deleted from the list of images returned by an API
> call."
> 
> It doesn't say the image is deleted immediately, or that it waits for
> the image to be gone before changing the instance status to ACTIVE.
> 
> I see there is also a typo in there, that should say after you
> successfully *unshelve* a server.
> 
> From an API user point of view, this is all asynchronous because it's an
> RPC cast from the nova-api service to the nova-conductor and finally
> nova-compute service when unshelving the instance.
> 
> So I think the test is making some wrong assumptions on how fast the
> image is going to be deleted when the instance is active.
> 
> As Ken'ichi pointed out in the Tempest change, Glance returns a 204 when
> deleting an image in the v2 API [2]. If the image delete is asynchronous
> then that should probably be a 202.
> 
> Either way the Tempest test should probably be in a wait loop for the
> image to be gone if it's really going to assert this.
> 

Thanks for confirming this.

What do we need to do to get this fixed in Tempest?  Nobody from Tempest
Core has responded to the revert patch [3] since this explanation was
posted.

IMO we should revert this for now and someone can implement a fixed
version if this test is needed.

[3] https://review.openstack.org/#/c/471352/

> [1]
> https://developer.openstack.org/api-ref/compute/?expanded=unshelve-restore-shelved-server-unshelve-action-detail#unshelve-restore-shelved-server-unshelve-action
> 
> [2]
> https://developer.openstack.org/api-ref/image/v2/index.html?expanded=delete-an-image-detail#delete-an-image
> 
>