Comment 3 for bug 1777978

Reviewed: https://review.openstack.org/584940
Committed: https://git.openstack.org/cgit/openstack/networking-ovn/commit/?id=fdff1ffa5c64b4898f25cb99bbe6001ebcab3321
Submitter: Zuul
Branch: stable/queens

commit fdff1ffa5c64b4898f25cb99bbe6001ebcab3321
Author: Numan Siddique <email address hidden>
Date: Thu Mar 22 16:07:26 2018 +0530

    Support per network dns domain name in internal OVN dns

    If user has set network's dns_domain attribute, this patch stores an
    additional record in the DNS.records column as
    <port host_name>.<net_dns_domain>=<IP ADDRESSES>

    This patch doesn't handle the scenario when a network's dns_domain
    is updated. This is presently left as TODO and it will be supported
    as a follow up patch.

    Handling the DNS entries in the OVN NB DB seems to become more complicated
    and I think it is better if we store the dns name of a port in
    Logical_Switch_Port.options column and the dns domain name and network's domain
    name in Logical_Switch.options and let ovn-northd read these values and update
    the OVN SB DB 'DNS' table. I will pursue this approach before addressing the
    above TODO.

    Change-Id: Ic9068d4bbb4602aa9d8c5d9cce8457b39057c802
    Partial-bug: #1777978
    (cherry picked from commit fb1b29e74ae7bfe30894fc0a0b840da697fecaee)