Comment 13 for bug 2019217

Reviewed: https://review.opendev.org/c/openstack/neutron/+/913574
Committed: https://opendev.org/openstack/neutron/commit/0a421118f2c724267c9e70b926b53136f55b575d
Submitter: "Zuul (22348)"
Branch: stable/2023.1

commit 0a421118f2c724267c9e70b926b53136f55b575d
Author: Rodolfo Alonso Hernandez <email address hidden>
Date: Wed May 24 07:15:35 2023 +0200

    [OVN] The L3 scheduler does not use all chassis by default

    Any OVN scheduler, inheriting from ``OVNGatewayScheduler``, calls
    ``_schedule_gateway`` to make the decision of in what chassis the
    router gatweway should be located. Before this patch, if the list
    of candidates was empty, the scheduler used all available chassis
    as candidate list. This patch is removing this default behaviour.
    In a deployment, only those chassis marked explicitly with
    "ovn-cms-options=enable-chassis-as-gw" can be used as gateway
    chassis.

    After enabling this patch, any existing router gateway port will
    preserve the assigned chassis; any new router gateway will be
    scheduled only on the chassis configured as gateways.

    If a router gateway port cannot find any chassis to be scheduled,
    the "neutron-ovn-invalid-chassis" will be used instead and a
    warning message will be printed in the logs.

    Closes-Bug: #2019217
    Change-Id: If0f843463edfd7edc5c897cc098de31444f9d81b
    (cherry picked from commit 413044f253b6d434164e8a94dbeccec7b1b79ebe)