[openstack-dev] [qa][cinder][ceph] should Tempest tests the backend specific feature?

Monty Taylor mordred at inaugust.com
Thu May 4 03:09:32 UTC 2017

On 05/02/2017 11:49 AM, Sean McGinnis wrote:
> On Tue, May 02, 2017 at 03:36:20PM +0200, Jordan Pittier wrote:
>> On Tue, May 2, 2017 at 7:42 AM, Ghanshyam Mann <ghanshyammann at gmail.com>
>> wrote:
>>> In Cinder, there are many features/APIs which are backend specific and
>>> will return 405 or 501 if same is not implemented on any backend [1].
>>> If such tests are implemented in Tempest, then it will break some gate
>>> where that backend job is voting. like ceph job in glance_store gate.
>>> There been many such cases recently where ceph jobs were broken due to
>>> such tests and recently it is for force-delete backup feature[2].
>>> Reverting force-delete tests in [3]. To resolve such cases at some
>>> extend, Jon is going to add a white/black list of tests which can run
>>> on ceph job [4] depends on what all feature ceph implemented. But this
>>> does not resolve it completely due to many reason like
>>> 1. External use of Tempest become difficult where user needs to know
>>> what all tests to skip for which backend
>>> 2. Tempest tests become too specific to backend.
>>> Now there are few options to resolve this:
>>> 1. Tempest should not tests such API/feature which are backend
>>> specific like mentioned by api-ref like[1].
>> So basically, if one of the 50 Cinder driver doesn't support a feature, we
>> should never test that feature ? What about the 49 other drivers ? If a
>> feature exists and can be tested in the Gate (with whatever default
>> config/driver is shipped) then I think we should test it.
> 50? Over 100 as of Ocata.
> Well, is tempest's purpose in life to provide complete gate test coverage,
> or is tempest's purpose in life to give operators a tool to validate that
> their deployment is working as expected?

I'd actually like to suggest that such a scenario actually points out a 
thing that is ultimately potential pain passed to the end user in the 
real world, so this question about what/how to test this in tempest is a 
good one to have.

If there is a feature which is only provisionally available depending on 
the backend driver such that it's hard to test in tempest without an out 
of band config - then it's a feature that a user will have no clue 
whether it works on a given cloud.

As we find these, I'd love it if we could expose discovery in the API 
for viability of the feature. Like:

GET /capabilities

   "capabilities": {
     "has_force_delete": true

(I know we've talked about that concept generally, but this is a 
specific example)

If such a thing existed, then the user can know whether they can use a 
thing .. and so can tempest. A tempest test to validate force_delete 
working could check the capability reported by the API and validate that 
if the API says "true" that the feature work as expected, and if it says 
"false" validate that attempting to call it returns a 405 (or whatever 
is appropriate)

Ultimately, every config we need to feed to tempest is potentially a 
place where an end user is unable to know whether or not to expect a 
call to work - and an opportunity for us to provide our API consumers 
with a richer experience.

> In attempting to do things in the past, I've received push back based on
> the argument that it was the latter. For this reason, in-tree tempest tests
> were added to Cinder to give us a way to get better test coverage for our
> own sake.
> Now that this is all in place, I think it's working well and I would like
> to see it continue that way. IMO, tempest proper should not have anything
> that isn't universally applicable to real world deployments. Not just for
> things like Ceph, but things like the manage/unmanage backend specific
> tests that were added and broke a large majority of third party CI.
> Backend specific things should not be part of tempest in my opinion. We
> should cover those things through in-tree tempest plugins and our own
> testing.
>>> 2. Tempest test can be disabled/skip based on backend. - This is not
>>> good idea as it increase config options and overhead of setting those.
>> Using regex and blacklist, any 3rd party CI can skip any test based on the
>> test ID. Without introducing a config flag. See:
>> https://github.com/openstack-infra/project-config/blob/1cea31f402b6b0cccc47cde203c12184b5392c90/jenkins/jobs/devstack-gate.yaml#L1871
>>> 3. Tempest test can verify behavior with if else condition as per
>>> backend. This is bad idea and lose the test strength.
>> Yeah, that's bad.
>>> IMO options 1 is better options. More feedback are welcome.
>>> ..1 https://developer.openstack.org/api-ref/block-storage/v3/?
>>> expanded=force-delete-a-backup-detail#force-delete-a-backup
>>> ..2 https://bugs.launchpad.net/glance/+bug/1687538
>>> ..3 https://review.openstack.org/#/c/461625/
>>> ..4 http://lists.openstack.org/pipermail/openstack-dev/2017-
>>> April/115229.html
>>> -gmann
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