---
deprecations:
  - |
    The L2 population ``agent_boot_time`` config option is deprecated in
    favor of the direct RPC agent restart state transfer. It will be
    removed in the ``Train`` release.
critical:
  - |
    The neutron-openvswitch-agent can sometimes spend too much time handling
    a large number of ports, exceeding its timeout value, ``agent_boot_time``,
    for L2 population. Because of this, some flow update operations will not
    be triggerred, resulting in lost flows during agent restart, especially
    for host-to-host vxlan tunnel flows, causing the original tunnel flows to
    be treated as stale due to the different cookie IDs. The agent's first
    RPC loop will also do a stale flow clean-up procedure and delete them,
    leading to a loss of connectivity.
    Please ensure that all neutron-server and neutron-openvswitch-agent
    binaries are upgraded for the changes to take effect, after which
    the L2 population ``agent_boot_time`` config option will no longer
    be used.
fixes:
  - |
    The neutron-openvswitch-agent was changed to notify the neutron-server
    in its first RPC loop that it has restarted. This signals neutron-server
    to provide updated L2 population information to correctly program FDB
    entries, ensuring connectivity to instances is not interrupted.
    This fixes the following bugs:
    `1794991 <https://bugs.launchpad.net/neutron/+bug/1794991>`_,
    `1799178 <https://bugs.launchpad.net/neutron/+bug/1799178>`_,
    `1813703 <https://bugs.launchpad.net/neutron/+bug/1813703>`_,
    `1813714 <https://bugs.launchpad.net/neutron/+bug/1813714>`_,
    `1813715 <https://bugs.launchpad.net/neutron/+bug/1813715>`_.
