Comment 15 for bug 1719574

Reviewed: https://review.openstack.org/606904
Committed: https://git.openstack.org/cgit/openstack/networking-ovn/commit/?id=93fccfb62ea0750fd10448b497f7a6cd4f12a828
Submitter: Zuul
Branch: stable/rocky

commit 93fccfb62ea0750fd10448b497f7a6cd4f12a828
Author: Daniel Alvarez <email address hidden>
Date: Fri Jun 15 01:36:36 2018 +0000

    Register OVN metadata as an agent

    This patch registers and lists the OVN metadata agent with Neutron.

    Since the OVN Controller / Gateway use the Chassis UUID as its own
    agent UUID, the OVN Metadata creates can't re-use that. Instead, this
    patch generates a random UUID for each Metadata agent and saves it to the
    external_ids' column in the Chassis table. At startup time, the metadata
    agent will check if the "neutron:ovn-metadata-id" key is present in the
    Chassis external_id column and use that UUID if it's there, otherwise
    it will generate a random UUID for it.

    This patch uses the same AgentStats mechanism to identify whether the
    OVN metadata agent is alive or not by relying on the "nb_cfg" from the
    Chassis. The only difference from the OVN controller agent is that the
    metadata will save the "nb_cfg" of it's last update into the Chassis
    external_ids column.

    Conflicts:
     networking_ovn/common/utils.py

    Co-Authored-By: Daniel Alvarez <email address hidden>
    Closes-Bug: #1719574
    Change-Id: Icfc9e76e8371d8f33b264df65ae3a7cbc0ca099e
    (cherry picked from commit 53a1c87cbf2de25e4d18696987179f40f6c5d67f)