Unable to create or delete nova instances

Issue

• After restarting the controller, instances fail to build and will either get stuck in the Build state or show the following error:

Error: Block Device Mapping is Invalid: Boot sequence for the instance and 
image/block device mapping combination is not valid. (HTTP 400) (Request-ID: 
req-<uuid>)

• Unable to delete instances as they stay stuck in the deleting state.
• Compute node(s) have lost their connection to libvirtd:

 [root@node0 tmp(keystone_linux_prod)]# nova service-list
+----+------------------+------------+----------+----------+-------+----------------------------+-------------------------------------+
| Id | Binary           | Host       | Zone     | Status   | State | Updated_at                 | Disabled Reason                     |
+----+------------------+------------+----------+----------+-------+----------------------------+-------------------------------------+
| 1  | nova-consoleauth | node0 | internal | enabled  | up    | 2015-10-13T19:30:43.000000 | -                                   |    
| 2  | nova-scheduler   | node0 | internal | enabled  | up    | 2015-10-13T19:30:52.000000 | -                                   |    
| 4  | nova-conductor   | node0 | internal | enabled  | up    | 2015-10-13T19:30:51.000000 | -                                   |    
| 5  | nova-cert        | node0 | internal | enabled  | up    | 2015-10-13T19:30:53.000000 | -                                   |    
| 6  | nova-compute     | node1 | nova     | enabled  | up    | 2015-10-13T19:30:51.000000 | None                                |
| 7  | nova-compute     | node2 | nova     | disabled | up    | 2015-10-13T19:30:45.000000 | AUTO: Connection to libvirt lost: 1 |
| 8  | nova-compute     | node3 | nova     | enabled  | up    | 2015-10-13T19:30:51.000000 | None                                |
| 9  | nova-compute     | node4 | nova     | enabled  | up    | 2015-10-13T19:30:47.000000 | None                                |
| 10 | nova-compute     | node5 | nova     | enabled  | up    | 2015-10-13T19:30:51.000000 | None                                |
| 11 | nova-compute     | node6 | nova     | disabled | up    | 2015-10-13T19:30:45.000000 | AUTO: Connection to libvirt lost: 1 |
| 12 | nova-compute     | node7 | nova     | enabled  | up    | 2015-10-13T19:30:44.000000 | None                                |
| 13 | nova-compute     | node8 | nova     | enabled  | up    | 2015-10-13T19:30:50.000000 | None                                |
+----+------------------+------------+----------+----------+-------+----------------------------+-------------------------------------+

• Cinder volume is down on the controller:

[root@node0 tmp(keystone_linux_prod)]# cinder service-list
+------------------+----------------+------+---------+-------+----------------------------+-----------------+
|      Binary      |      Host      | Zone |  Status | State |         Updated_at         | Disabled Reason |
+------------------+----------------+------+---------+-------+----------------------------+-----------------+
| cinder-scheduler |   node0   | nova | enabled |   up  | 2015-10-13T19:31:38.000000 |       None      |
|  cinder-volume   | node0@nfs | nova | enabled |  down | 2015-07-16T04:31:34.000000 |       None      |
|  cinder-volume   | node0@rbd | nova | enabled |   up  | 2015-10-13T19:31:40.000000 |       None      |
+------------------+----------------+------+---------+-------+----------------------------+-----------------+

• Errors are seen in the cinder volume log:

2015-10-12 11:01:56.031 10969 ERROR cinder.volume.flows.manager.create_volume [req-<uuid> <uuid> <uuid> - - -] Failed to copy image <uuid> to volume: <uuid>, error: [Errno 28] No space left on device
2015-10-12 11:01:56.035 10969 WARNING cinder.volume.manager [req-<uuid> <uuid> <uuid> - - -] Task 'cinder.volume.flows.manager.create_volume.CreateVolumeFromSpecTask;volume:create' (<uuid>) transitioned into state 'FAILURE'