[all][interop][cinder][qa] API changes with/without microversion and Tempest verification of API interoperability
---- On Tue, 17 Sep 2019 07:59:19 +0900 Sean Mooney <smooney at redhat.com> wrote ----
> On Mon, 2019-09-16 at 17:11 -0500, Sean McGinnis wrote:
> > >
> > > Backend/type specific information leaking out of the API dynamically like
> > > that is definitely an interoperability problem and as you said it sounds
> > > like it's been that way for a long time. The compute servers diagnostics API
> > > had a similar problem for a long time and the associated Tempest test for
> > > that API was disabled for a long time because the response body was
> > > hypervisor specific, so we eventually standardized it in a microversion so
> > > it was driver agnostic.
> > >
> > Except this isn't backend specific information that is leaking. It's just
> > reflecting the configuration of the system.
> yes and config driven api behavior is also an iterop problem.
> ideally you should not be able to tell if cinder is abcked by ceph or emc form the
> api responce at all.
> sure you might have a volume type call ceph and another called emc but both should be
> report capasty in the same field with teh same unit.
> ideally you would have a snapshots or gigabytes quota and option ly associate that with a volume types
> but shanshot_ceph is not interoperable aross could if that exstis with that name solely becaue ceph was used on the
> backend. as a client i would have to look at snapshost* to figure out my quotat and in princiapal that is an ubounded
Yeah and this is real pain point for end-user or app using API directly. Dynamic API behaviour base don system configuration is interoperability issue.
In bug#1687538 case, new field is going to be reflected for the same backend and same configuration Cloud. Cloud provider upgrade their cloud from ocata->anything and user will start getting the new field without any mechanism to discover whether that field is expected to be present or not.