I think the response above is only valid when the VM had never been started.  If the VM was ever made active it would have been assigned an IP.

As a client of DNS i should not be dependent on the VM run state.  In fact, nova still reports the IP for the VM regardless of the state. for example:

root@gngsvm009d:/opt/contrail/utils# nova show 0cb1d9ab-573a-47a2-9a15-80aa91f274c5
+--------------------------------------+--------------------------------------------------------------------------------------------------+
| Property                             | Value                                                                                            |
+--------------------------------------+--------------------------------------------------------------------------------------------------+
| OS-DCF:diskConfig                    | MANUAL                                                                                           |
| OS-EXT-AZ:availability_zone          | nova                                                                                             |
| OS-EXT-SRV-ATTR:host                 | gngsvc018d                                                                                       |
| OS-EXT-SRV-ATTR:hypervisor_hostname  | gngsvc018d                                                                                       |
| OS-EXT-SRV-ATTR:instance_name        | instance-00000f25                                                                                |
| OS-EXT-STS:power_state               | 4                                                                                                |
| OS-EXT-STS:task_state                | -                                                                                                |
| OS-EXT-STS:vm_state                  | stopped                                                                                          |
| OS-SRV-USG:launched_at               | 2014-12-09T01:39:26.000000                                                                       |
| OS-SRV-USG:terminated_at             | -                                                                                                |
| accessIPv4                           |                                                                                                  |
| accessIPv6                           |                                                                                                  |
| config_drive                         |                                                                                                  |
| created                              | 2014-12-09T01:39:13Z                                                                             |
| flavor                               | jbm-std (097059e7-d6ce-4c23-9fce-4504816771e4)                                                   |
| hostId                               | 155ee1eb84b05b3d1ecb5387856122bb664d2b83a74c8fea6c557d00                                         |
| id                                   | 0cb1d9ab-573a-47a2-9a15-80aa91f274c5                                                             |
| image                                | JBM-Primary-Snap (416c6e33-fb6c-4a96-a700-f2a1de22f0cd)                                          |
| key_name                             | -                                                                                                |
| metadata                             | {"delivered_to": "XXX"}                                                                         |
| name                                 | jbm-contrail-vm003                                                                               |
| os-extended-volumes:volumes_attached | [{"id": "143fb12d-d624-4982-b427-7c51c169c742"}, {"id": "c7aa6705-0e7b-430b-9f27-b33b267dc789"}] |
| performance_net network              | 192.168.1.8, 10.163.0.8                                                                          |
| security_groups                      | default                                                                                          |
| status                               | SHUTOFF                                                                                          |
| tenant_id                            | 2aeeb862495944289c64601f1bd218ca                                                                 |
| updated                              | 2015-01-25T04:41:48Z                                                                             |
| user_id                              | 7bb36e4bf9ec4009b706a66fed020dc1                                                                 |
+--------------------------------------+--------------------------------------------------------------------------------------------------+

also, as a side comment dynamic DNS follows the DHCP lease lifecycle, not a server activity lifecycle.   Just because the current implementation has tied these 2 concepts together does not justify the behavior.

Further, a floating IP assignment is essentially a static binding and should be valid for the lifetime of the association regardless of the VM activity.  This stickiness is very important for clients that exist outside the virtual environment.