Comment 5 for bug 1916758

Reviewed: https://review.opendev.org/c/openstack/python-tripleoclient/+/791089
Committed: https://opendev.org/openstack/python-tripleoclient/commit/050c9aa99fc6a3818ae37fe6382318be9f59706d
Submitter: "Zuul (22348)"
Branch: stable/train

commit 050c9aa99fc6a3818ae37fe6382318be9f59706d
Author: David Vallee Delisle <email address hidden>
Date: Thu May 13 03:47:47 2021 +0000

    [train-only] post stack creation tsx validation

    RHEL-8.3 kernel disabled the Intel TSX (Transactional
    Synchronization Extensions) feature by default as a preemptive
    security measure, but it breaks live migration from RHEL-7.9
    (or even RHEL-8.1 or RHEL-8.2) to RHEL-8.3.

    Operators are expected to explicitly define the TSX flag in
    their KernelArgs for the compute role to prevent live-migration
    issues during the upgrade process.

    This is explained in detail in this article [a]

    If operators don't want to add the TSX flag to the KernelArgs,
    they can always set "ForceNoTsx" to true.

    Adding this mandatory validation right after the stacks are
    updated is probably the earliest place where we can validate
    and fail if necessary. We'd rather fail quickly than too late
    as this will provide the best experience for our users.

    In addition to this, there's a tripleo-validation [b] in the
    work.

    This is meant to be train-only for now but we will have to
    refactor if (when?) we support FFU from queens to Wallaby+

    [a] https://access.redhat.com/solutions/6036141
    [b] https://review.opendev.org/c/openstack/tripleo-validations/+/790806

    Co-Authored-By: Martin Schuppert <email address hidden>
    Related: https://bugzilla.redhat.com/1923165
    Closes-Bug: #1916758
    Change-Id: I35246fbf74394f6e315973283464085d2aef08b2