Error Handling is not proper as wrong error message during migration and stoping of nova instance at same time

[Manik Bindlish]

Release: Stable Newton
Ubuntu 16.04
Environment for NFV

Note: Instance is part of VNF, created from tacker

controller:~/toscatmplts$ nova list --all
+--------------------------------------+-------------------------------------------------------+----------------------------------+--------+------------+-------------+---------------------+
| ID | Name | Tenant ID | Status | Task State | Power State | Networks |
+--------------------------------------+-------------------------------------------------------+----------------------------------+--------+------------+-------------+---------------------+
| 9fc24e9a-5a14-48d6-8dd6-5868f85aa5ed | ta-4034-9a0d-d35d24244dbe-RESPAWN-2-VDU1-updnuz4i3ncx | 3f63cd58b8394fe5a08b4d2bd2e97a71 | ACTIVE | - | Running | mgmt=192.168.104.21 |
+--------------------------------------+-------------------------------------------------------+----------------------------------+--------+------------+-------------+---------------------+
controller:~/toscatmplts$ nova migrate 9fc24e9a-5a14-48d6-8dd6-5868f85aa5ed & nova stop 9fc24e9a-5a14-48d6-8dd6-5868f85aa5ed
[1] 23860

Request to stop server 9fc24e9a-5a14-48d6-8dd6-5868f85aa5ed has been accepted.
ERROR (ClientException): Unexpected API Error. Please report this at http://bugs.launchpad.net/nova/ and attach the Nova API log if possible.
<class 'nova.exception.UnexpectedTaskStateError'> (HTTP 500) (Request-ID: req-de9fd9aa-33f1-488e-9b90-f6d0bdace088)

There should be proper error message

[jichenjc (jichenjc)]

Please help to provide nova logs such as api/conductor/scheduler/compute for further analysis

[Launchpad Janitor (janitor)]

[Expired for OpenStack Compute (nova) because there has been no activity for 60 days.]