Consider making upgrade check for old computes a failure

[Pierre Riteau]

Currently, the upgrade check for older than N-1 computes only produces a warning.
For example:

Check: Older than N-1 computes
Result: Warning
Details: Current Nova version does not support computes older than
  Victoria but the minimum compute service level in your
  system is 30 and the oldest supported service level is 52.

If this is overlooked, Nova services will fail to start after upgrade. With Nova API down, the old services cannot be removed without database edits.

Is there a specific reason to keep this check as a warning rather than a failure?

[Sylvain Bauza (sylvain-bauza)]

I'm not sure I'd classify it as a bug. Probably a good thought so, so marking it Invalid/Wishlist but I'm open to thoughts.

To answer your question, now that we have an hardstop blocking nova services to restart if there are old enough, this sound a legit blueprint to address.

[Balazs Gibizer (balazs-gibizer)]

This is already an error since Wallaby https://review.opendev.org/c/openstack/nova/+/738482

[Pierre Riteau (priteau)]

@gibi: which is why I am suggesting the upgrade check should be fatal, since presence of old computes is fatal for nova

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/openstack/nova/+/845262

[Balazs Gibizer (balazs-gibizer)]

I misunderstood this issue originally. Now I see that it is targeting the upgrade check. I agree that it should be changed from WARNING to FAILURE

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/nova/+/845262
Committed: https://opendev.org/openstack/nova/commit/9af4c6115fcfce9c76a1e7fd5b93bb43cec66a4d
Submitter: "Zuul (22348)"
Branch: master

commit 9af4c6115fcfce9c76a1e7fd5b93bb43cec66a4d
Author: Pierre Riteau <email address hidden>
Date: Thu Jun 9 20:56:26 2022 +0200

    Change TooOldComputeService upgrade check code to failure

    The TooOldComputeService upgrade check currently produces a warning,
    which may be missed if the upgrade process only checks the exit code of
    the upgrade check command.

    Since this can lead to Nova control services failing to start, make the
    upgrade check a failure instead, so it results in a non-zero exit code.

    Closes-Bug: #1956983
    Change-Id: Ia3ce6a0b0b810667ac0a66502a43038fe43c5aed