OpenStack DNS Updater listens on the RabbitMQ message bus. Whenever an instance is created or deleted DNS updater creates or removes its DNS A record. The name of the instance is directly used as its FQDN. Hence instances in OpenStack should be named with their FQDN. The IP address stored in DNS is the IP address of the first network interface on the private network. You can easily change the script to store floating IP address in DNS instead.
OpenStack DNS Updater works well on CentOS 7. You can copy it into your
/usr/local/bin directory and run it as user "nova". See the accompanying
systemd script. OpenStack DNS Updater logs into /var/log/nova/dns-updater.log
by default.
For using Ubuntu (upstart) you can copy
openstack-dns-updater.upstart to /etc/init/openstack-dns-updater.conf and
run service openstack-dns-updater start.
For more information refer to: http://alesnosek.com/blog/2015/05/31/openstack-dynamic-dns-updates/