Comment 15 for bug 2074209

Reviewed: https://review.opendev.org/c/openstack/neutron/+/925710
Committed: https://opendev.org/openstack/neutron/commit/910821805907a1800d0dd875e9af41352c80cf5a
Submitter: "Zuul (22348)"
Branch: stable/2023.2

commit 910821805907a1800d0dd875e9af41352c80cf5a
Author: Slawek Kaplonski <email address hidden>
Date: Tue Jul 30 14:17:44 2024 +0200

    Lower spacing time of the OVN maintenance tasks which should be run once

    Some of the OVN maintenance tasks are expected to be run just once and
    then they raise periodic.NeverAgain() to not be run anymore. Those tasks
    also require to have acquried ovn db lock so that only one of the
    maintenance workers really runs them.
    All those tasks had set 600 seconds as a spacing time so they were run
    every 600 seconds. This works fine usually but that may cause small
    issue in the environments were Neutron is run in POD as k8s/openshift
    application. In such case, when e.g. configuration of neutron is
    updated, it may happen that first new POD with Neutron is spawned and
    only once it is already running, k8s will stop old POD. Because of that
    maintenance worker running in the new neutron-server POD will not
    acquire lock on the OVN DB (old POD still holds the lock) and will not
    run all those maintenance tasks immediately. After old POD will be
    terminated, one of the new PODs will at some point acquire that lock and
    then will run all those maintenance tasks but this would cause 600
    seconds delay in running them.

    To avoid such long waiting time to run those maintenance tasks, this
    patch lowers its spacing time from 600 to just 5 seconds.
    Additionally maintenance tasks which are supposed to be run only once and
    only by the maintenance worker which has acquired ovn db lock will now be
    stopped (periodic.NeverAgain will be raised) after 100 attempts of
    run.
    This will avoid running them every 5 seconds forever on the workers
    which don't acquire lock on the OVN DB at all.

    Conflicts:
        neutron/plugins/ml2/drivers/ovn/mech_driver/ovsdb/maintenance.py
        neutron/tests/unit/plugins/ml2/drivers/ovn/mech_driver/ovsdb/test_maintenance.py

    Closes-bug: #2074209
    Change-Id: Iabb4bb427588c1a5da27a5d313f75b5bd23805b2
    (cherry picked from commit 04c217bcd0eda07d52a60121b6f86236ba6e26ee)
    (cherry picked from commit 78900c12f3c398b9f974531bbf61ce5c8e852770)