[ovirt-devel] OST: A good way to test cluster compatibility version upgrade?

[Milan Zamazal]

Hi, we'd like to test cluster compatibility version upgrades in OST and
we're thinking whether there is a good way to do that without putting
much burden on OST.  We want to test that the cluster updates without
errors, as well as the VMs in it.

A safe way would be to create a new data center for that purpose and run
the test on it.  But some operations, such as adding a host or a
storage, are slow.  Maybe we could initialize the data center in
parallel with the current test data center but then we'd need an
additional Lago host, which might increase memory requirements, already
high enough.

We might create a new data center and cluster without running hosts and
running VMs but then the test would be limited in its extent.

Another possibility is to reuse the current test data center.  We could
create it with the oldest support compatibility version, rather than
current compatibility version, and perform upgrades on it up to the
current compatibility version.  Then we would continue with the tests
normally.  The overhead, besides testing the upgrades themselves, could
be minimal.  The disadvantage would be that we wouldn't test the
current-compatibility-version creation process directly.

We could also make a separate test suite for that test, but is it
desirable and would anybody run it regularly?

So what do you recommend as a good way to test cluster compatibility
version upgrades?

Thanks,
Milan