Comment 2 for bug 1970205

Reviewed: https://review.opendev.org/c/starlingx/config/+/839202
Committed: https://opendev.org/starlingx/config/commit/e3686678caf0181f230c8ddc0ca9ce5abb916e81
Submitter: "Zuul (22348)"
Branch: master

commit e3686678caf0181f230c8ddc0ca9ce5abb916e81
Author: John Kung <email address hidden>
Date: Mon Apr 25 08:54:23 2022 -0400

    Disallow route config during upgrade states

    It is observed that a subcloud add operation following upgrade-start
    will result in a route config operation which will not be applied
    on the N+1 side.

    After an upgrade-start, which snapshots the config database,
    config operations could prevent an upgrade from being orchestrated.

    Route config operations are now disallowed until after the
    N+1 controller is upgraded and during upgrade abort (as the abort's
    not cancellable) as the load is being returned to the N load.

    After the N+1 controller is upgraded, allow route config operations as
    either the upgrade will complete and the system will be consistent;
    or the operation can be aborted,
    and the system restored to backedup state.

    Tox unit tests added to cover the route config during various
    upgrade states.

    Closes-Bug: 1970205

    Test Plan:
    PASSED route tox unit tests
    PASSED Disallow route config during Upgrade
    PASSED SystemController Duplex Upgrade
    PASSED Distributed Cloud Subcloud Upgrade
    PASSED Simplex Upgrade

    Signed-off-by: John Kung <email address hidden>
    Change-Id: If0cc68286ec87858b0517234e8bb08c4ed2ad851