Comment 22 for bug 1891360

Reviewed: https://review.opendev.org/c/openstack/neutron/+/797761
Committed: https://opendev.org/openstack/neutron/commit/8eaa61e916da62d4246a964e7bbcb81b9d5a8506
Submitter: "Zuul (22348)"
Branch: stable/rocky

commit 8eaa61e916da62d4246a964e7bbcb81b9d5a8506
Author: Slawek Kaplonski <email address hidden>
Date: Fri Apr 23 10:45:14 2021 +0200

    Remove FIP agent's gw port when L3 agent is deleted

    Floating IP agent gateway ports are created for each external network
    for each node where DVR L3 agent is running and where there is some FIP
    from the ext_net.
    But even, if L3 agent is removed (e.g. when scaling down the cluster),
    such floating IP gateway port is never removed so it consumes IP address
    from the external network.

    With this patch when the DVR L3 agent is deleted, all such fip gateway
    ports owned by that agent will be deleted.
    When new L3 agent is created (registered in the DB), Neutron will check
    if there are any floating IPs on that host and will recreate such FIP
    gateway ports for it.

    Conflicts:
        neutron/tests/unit/db/test_l3_dvr_db.py

    Closes-Bug: #1891360
    Change-Id: If6ef990baf039c556d7420962ac4c54608711f06
    (cherry picked from commit 8cc7c0cf7a5196103b097fae67eccbd5dc3980ac)