Open Stack

Thanks for bringing this up Ken’ichi!  Folks who aren’t familiar with Nova’s move to microversioning may want to peruse the spec that was implemented in Kilo [1] and note that some other projects like Neutron are headed in this direction as well [2]. 
 
The basic idea of this patch is to not allow any additional properties in API responses (even if all the nova-supported properties are included) because Nova has moved to a microversioned API as of Kilo [1], correct?  And if a cloud wants to provide additional attributes in API responses, it should now bump the monotonic version counter to make clear to clients that it does so?  From a DefCore perspective, I imagine the concern here is how this change affects clouds built on older versions of OpenStack since Tempest is branchless.  A DefCore Guideline typically covers three OpenStack releases: the next Guideline will likely cover Juno, Kilo, and Liberty.  Clouds built on Juno predate the move to Nova microversioning.  In theory there could be Juno-based clouds that provide all of the “OpenStack” properties in API responses, but add some additional properties as well.  Such clouds might run into trouble when running RefStack because Tempest will now enforce that no additional properties may be added to API responses even on clouds that predate the move to microversioning.

Have I understood the concern correctly?

[1] http://specs.openstack.org/openstack/nova-specs/specs/kilo/implemented/api-microversions.html
[2] Such as Neutron: http://specs.openstack.org/openstack/neutron-specs/specs/liberty/microversioning.html

At Your Service,

Mark T. Voelker

> On Jun 19, 2015, at 5:16 AM, Ken'ichi Ohmichi <ken1ohmichi at gmail.com> wrote:
> 
> Hi,
> 
> There is a related patch of Tempest[1].
> With this patch, Tempest will block additional(including
> vendor-specific) parameters on a response of Nova REST API.
> So after that, I think Refstack also will deny clouds which provide
> such REST API services, because it uses Tempest tests.
> I believe this way will make OpenStack interoperability better and
> upstream-first trend will be more strong.
> But this change affects DefCore thing, so I'd like to notice this and
> get feedback.
> # During writing this mail, the patch is approved anyway.
> 
> Thanks
> Ken Ohmichi
> 
> ---
> [1]: https://review.openstack.org/#/c/156130/
> 
> 2015-06-18 12:07 GMT+09:00 Mark Voelker <mvoelker at vmware.com>:
>>> On Jun 17, 2015, at 8:51 PM, Rochelle Grober <rochelle.grober at huawei.com> wrote:
>>> 
>>> I'm replying to this version of John's mail to expand on his "use case" point.
>>> 
>>> What John calls a use case is, in this instance, the same as a high level "Test Case".  Essentially, this is the documentation/comments that define what the test(s) for this case are doing.  DefCore (or others) could create these high level test cases and use them as the framework into which new tests, specific for the capability, could be written.  This, I think, would be an ideal way to start documenting missing capabilities tests.  For some capabilities, there could be multiple use cases (or test cases) that define the capability.
>>> 
>>> This could also be used for existing tests, but instead of including code for each case or step in a case, the git repo link to the existing test could be included.  This process could also be used with new tests being linked into the test case document as they are merged into the trunk.
>>> 
>>> This process provides the higher level test "specs" that developers implement into tests.  It provides both a way to track what tests exist and what don't, and a description of the capability that is understandable by end users and other interested parties not concerned with the "guts," but just the behavior of the capability.
>>> 
>>> For the case of multiple ways of performing an action, the tests would need to implement all methods that meet DefCore criteria.  If any of the methods result in the appropriate end result, then for DefCore purposes, the test has passed.
>> 
>> Maybe I’m misunderstanding, but this seems hugely problematic for interoperability.  If we say there’s more than one way to do a thing but you pass if you implement any one of those ways, then app developers still don’t know what methods they can depend on being available.  Instead of interoperable clouds we have clouds that can do the same things but for which I still have to write a bunch of this**:
>> 
>> def list_images():
>>   “”” A function to list images. Because all OpenStack Powered Platforms can do that…somehow.””"
>>   if $cloud == ‘vendorA’:
>>      # TODO: this also works for vendorX
>>      list_images_via_nova_image_api()
>>   elif $cloud == ‘vendorB’:
>>      # TODO: this also worked for vendorY last week but now, um?
>>      list_images_via_glance_v1()
>>   elif $cloud == ‘vendorC’:
>>      list_images_via_glance_v2()
>>   else:
>>      # I dunno what cloud this is, but it’s OpenStack Powered! So something must work.
>>      try:
>>         list_images_via_nova_image_api()
>>      except NopeError:
>>          # D’oh, guess that wasn’t it…
>>          try:
>>             list_images_via_glance_v1()
>>          except StillNopeError:
>>             # Aww…well third time’s the charm?
>>             try:
>>                list_images_via_glance_v2()
>>             except NopeNopeNopeError:
>>                rage_quit()
>> 
>> into any app that I want to be able to run on OpenStack Powered Platforms.  Which is a Bad Thing and basically where we’re at now.  How you expose a capability matters tremendously.  IMHO, interoperability by if/else loop isn’t interoperability at all.
>> 
>> ** I’m strawmanning slightly here in that I’m pretending these three methods all somehow met DefCore criteria, but you get the picture.
>> 
>> At Your Service,
>> 
>> Mark T. Voelker
>> 
>>> 
>>> Does this make sense for DefCore?  As OpenStack matures and acts more like a collection of products rather than a collection of code bases, the processes and collateral of software process that exist to turn code into product come more into play. Hence, the QA as not just verification gate, but a measurement and metrics repository.
>>> 
>>> Sorry!  Had to get this thought out.  You don't need the QA that most SW companies have until you have product.  We are getting close to one and so are now in need of expanding OpenStack QA to encompass the other.
>>> 
>>> --Rocky
>>> 
>>> 
>>> 
>>> -----Original Message-----
>>> From: John Garbutt [mailto:john at johngarbutt.com]
>>> Sent: Wednesday, June 17, 2015 09:57
>>> To: defcore-commit.
>>> Cc: Nikhil Komawar
>>> Subject: [OpenStack-DefCore] Image APIs in Glance and Nova
>>> 
>>> Hi,
>>> 
>>> So this was raised in the cross project meeting, and thank you for that.
>>> 
>>> I keep mentioning use cases, so here we go...
>>> * create from cloud base image for ubuntu 12.04
>>> * above but with boot from volume
>>> * create a snapshot
>>> * download snapshot
>>> * upload image into another openstack cloud
>>> * boot server from uploaded image
>>> 
>>> Now, at a higher level:
>>> * user does above using custom script for Cloud A and Cloud B
>>> * user keeps to just the APIs that are defcore tested
>>> * user gets access to Cloud C and Cloud D
>>> * user wants to point script at new clouds, and everything should just work
>>> 
>>> So I think thats where we want to be. Now lets dig in...
>>> 
>>> To list images, the user could:
>>> * use nova to list images (stable, but project wants to delete it)
>>> * use glance v1 (should never be exposed to end users, was designed as
>>> internal only API)
>>> * use glance v2 (only just released, not really deployed anywhere)
>>> 
>>> For the
>>> 
>>> _______________________________________________
>>> Defcore-committee mailing list
>>> Defcore-committee at lists.openstack.org
>>> http://lists.openstack.org/cgi-bin/mailman/listinfo/defcore-committee
>>> 
>>> _______________________________________________
>>> Defcore-committee mailing list
>>> Defcore-committee at lists.openstack.org
>>> http://lists.openstack.org/cgi-bin/mailman/listinfo/defcore-committee
>> 
>> _______________________________________________
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