Open Stack

Hi nova-api team,

I'd like to get a feedback about the way to bump a microversion.

Short version:
  We found a validation bug on Nova v2.1 API.
  To fix the bug, do we need to bump a new microversion?

Long version:
As LP bug report[1], nova v2.0 API allows a list of server-IDs on
scheduler_hint "different_host" like

    "os:scheduler_hints": {
        "different_host": [
            "099b8bee-9264-48fe-a745-45b22f7ff79f",
            "99644acc-8893-4656-9481-0114efdbc9b6"
        ]
    }

on "create a server" API.
However, nova v2.1 API is handling this request as invalid because the
validation implementation way is wrong now.
Nova v2.1 API should allow the list of server-IDs for backwards compatibility.

We are trying to fix this bug on
https://review.openstack.org/#/c/259247/ , and we have a question to
fix it.
This fix is API change even if fixing the bug, so do we need to bump a
microversion?

The one usage of microversions is notification of API change.
If bumping it, nova can notify the fixing with a microversion.

This fix should be applied to stable branches also because of helping
the existing users.
So if bumping a microversion on stable branch also, the microversion
number meanings become different between clouds which are deployed
with different nova releases.
So we(John, Alex, me) are guessing we should not bump a microversion
on stable branches. but if doing that, nova cannot notify the fixing
on stable branches.

Now I am feeling this fixing will be applied without a microversion
bump because it is nice to avoid different microversion meanings of
master/stable branches.
Is it fine for us?

Thanks
Ken Ohmichi

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[1]: https://launchpad.net/bugs/1521928