Comment 2 for bug 1989986

I'm testing with master branch in devstack:

1) If I start with my-domain.org in neutron.conf I get:

$ sudo ovn-nbctl list dns
_uuid : a0ea42b1-0995-4b42-b88f-2c716cb57267
external_ids : {ls_name=neutron-1a2837f9-289e-407a-93d4-bdec59e09316}
records : {"11.0.0.10.in-addr.arpa"=red-1.my-domain.org, "12.0.0.10.in-addr.arpa"=red-2.my-domain.org, red-1="10.0.0.11", red-1.my-domain.org="10.0.0.11", red-2="10.0.0.12", red-2.my-domain.org="10.0.0.12"}

_uuid : b0e85319-194a-4563-b51c-6b5e035165b7
external_ids : {ls_name=neutron-241f9a69-c921-447c-af35-c1994316274b}
records : {}

_uuid : 3cd62b8b-3700-409f-993c-2f2c31492f2d
external_ids : {ls_name=neutron-d0091d63-b31c-407f-a0f6-56d91afa8e07}
records : {"11.0.0.20.in-addr.arpa"=blue-1.my-domain.org, "12.0.0.20.in-addr.arpa"=blue-2.my-domain.org, blue-1="20.0.0.11", blue-1.my-domain.org="20.0.0.11", blue-2="20.0.0.12", blue-2.my-domain.org="20.0.0.12"}

2) Changing dns_domain in neutron.conf to my-domain-1.org:

$ grep -r dns_domain /etc/neutron/neutron.conf
dns_domain = my-domain-1.org

3) Re-starting the neutron server and then creating a server:

$ openstack server create --flavor m1.nano --image 49d88d48-15a9-47be-8a7d-a9764f4e642c --security-group test --network private test -c id -f yaml
id: fac57b1b-f712-44a2-88e6-00a0f13d5906

$ openstack server list -c Networks -f yaml
- Networks:
    private:
    - 10.0.0.37
    - fda7:e83f:3098:0:f816:3eff:feab:e581

4) Then I get in the nbdb:

$ sudo ovn-nbctl list dns
_uuid : a0ea42b1-0995-4b42-b88f-2c716cb57267
external_ids : {ls_name=neutron-1a2837f9-289e-407a-93d4-bdec59e09316}
records : {"11.0.0.10.in-addr.arpa"=red-1.my-domain.org, "12.0.0.10.in-addr.arpa"=red-2.my-domain.org, red-1="10.0.0.11", red-1.my-domain.org="10.0.0.11", red-2="10.0.0.12", red-2.my-domain.org="10.0.0.12"}

_uuid : b0e85319-194a-4563-b51c-6b5e035165b7
external_ids : {ls_name=neutron-241f9a69-c921-447c-af35-c1994316274b}
records : {"1.8.5.e.b.a.e.f.f.f.e.3.6.1.8.f.0.0.0.0.8.9.0.3.f.3.8.e.7.a.d.f.ip6.arpa"=test.my-domain-1.org, "37.0.0.10.in-addr.arpa"=test.my-domain-1.org, test="10.0.0.37 fda7:e83f:3098:0:f816:3eff:feab:e581", test.my-domain-1.org="10.0.0.37 fda7:e83f:3098:0:f816:3eff:feab:e581"}

_uuid : 3cd62b8b-3700-409f-993c-2f2c31492f2d
external_ids : {ls_name=neutron-d0091d63-b31c-407f-a0f6-56d91afa8e07}
records : {"11.0.0.20.in-addr.arpa"=blue-1.my-domain.org, "12.0.0.20.in-addr.arpa"=blue-2.my-domain.org, blue-1="20.0.0.11", blue-1.my-domain.org="20.0.0.11", blue-2="20.0.0.12", blue-2.my-domain.org="20.0.0.12"}

So, the new instance got a port with the new value for dns_domain in neutron.conf. The entries in nbdb that were there before changing dns_domain preserved their value. Seems to me the correct behavior and I suspect it is the same in Ussuri. Did you try creating a new instance?

Marking it as incomplete for now. Please feel free to provide further info

Cheers