system-config/inventory/service/group_vars/adns.yaml

iptables_extra_allowed_hosts:
  - protocol: tcp
    port: 53
    hostname: ns1.opendev.org
  - protocol: tcp
    port: 53
    hostname: ns2.opendev.org
  - protocol: tcp
    port: 53
    hostname: ns1.openstack.org
  - protocol: tcp
    port: 53
    hostname: ns2.openstack.org