Comment 3 for bug 2044493

Reviewed: https://review.opendev.org/c/starlingx/config/+/901816
Committed: https://opendev.org/starlingx/config/commit/c645ce21d6272e92b4546ded808205088874f4bd
Submitter: "Zuul (22348)"
Branch: master

commit c645ce21d6272e92b4546ded808205088874f4bd
Author: Chris Friesen <email address hidden>
Date: Fri Nov 24 02:00:39 2023 -0600

    disable image gc when doing k8s upgrade

    Static pods cannot use image pull secrets, so it's important that the
    control plane images are not garbage-collected while we're doing a
    Kubernetes upgrade otherwise the upgrade can fail.

    Accordingly we want to disable garbage-collecting the images, then
    pre-pull the new images, then do the actual K8s upgrade, then re-enable
    image garbage collection.

    For duplex systems we can disable garbage collection from the puppet
    manifest, but for simplex puppet isn't involved so we have to do it
    from sysinv.

    The re-enabling of the image garbage collection happens when we
    upgrade kubelet to the final desired version. It's done in the
    puppet commit linked below.

    Depends-On: https://review.opendev.org/c/starlingx/stx-puppet/+/901778

    TEST-PLAN:

    PASS: Perform single-verison K8s upgrade on AIO-SX, ensure upgrade
          passes and image garbage collection is disabled when we
          download images and re-enabled when kubelet gets upgraded.

    Closes-Bug: 2044493

    Change-Id: Ide258768c3b05a01c4e903e52380a348c2fcae65
    Signed-off-by: Chris Friesen <email address hidden>