Instance failed to unshelve after compute failure

Solution Verified - Updated -


  • Red Hat Openstack Platform 13, 16


Instance without host assignment and in active or resize state.

Commands unshelve, reboot and rebuild failing.


Open a support case and mention this KCS.

Root Cause

Commands failed after compute restart.

Diagnostic Steps

  • The original compute node is failed or restarted, so the instance needed to be shelved.
  • The server show command will return a value None to hypervisor_hostname and host, also status as active instead of shelved.
(overcloud) [stack@director ~]$ openstack server show  <VM>
| Field                               | Value                                                                |
| OS-DCF:diskConfig                   | MANUAL                                                               |
| OS-EXT-AZ:availability_zone         |                                                                      |
| OS-EXT-SRV-ATTR:host                | None                                                                 |
| OS-EXT-SRV-ATTR:hypervisor_hostname | None                                                                 |
| status                              | ACTIVE                                                               |
  • A hard reboot will show the error below:
(overcloud) [stack@director ~]$ openstack server reboot --hard --wait <VM>
Unexpected API Error. Please report this at and attach the Nova API log if possible.
<class 'nova.exception.NovaException'> (HTTP 500) (Request-ID: req-f0f793c8-5cbd-4954-991a-a6f25dfb96ed)
  • Unshelve and rebuild will show the error below
(overcloud) [stack@director ~]$ openstack server rebuild <VM>
'unicode' object has no attribute 'get'

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