Here is the pretty obvious failure in the cells v1 logs:

http://logs.openstack.org/06/425806/8/check/gate-tempest-dsvm-cells-ubuntu-xenial/ab0bba2/logs/screen-n-cell-child.txt.gz?level=TRACE#_2017-01-31_01_25_10_115

2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging [req-a820f01f-ff4d-4c62-8a71-ba509d2061aa tempest-TestVolumeSwap-893937839 tempest-TestVolumeSwap-893937839] Error processing message locally
2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging Traceback (most recent call last):
2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging   File "/opt/stack/new/nova/nova/cells/messaging.py", line 188, in _process_locally
2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging     resp_value = self.msg_runner._process_message_locally(self)
2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging   File "/opt/stack/new/nova/nova/cells/messaging.py", line 1275, in _process_message_locally
2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging     return fn(message, **message.method_kwargs)
2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging   File "/opt/stack/new/nova/nova/cells/messaging.py", line 677, in run_compute_api_method
2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging     return fn(message.ctxt, *args, **method_info['method_kwargs'])
2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging   File "/opt/stack/new/nova/nova/compute/api.py", line 170, in inner
2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging     return function(self, context, instance, *args, **kwargs)
2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging   File "/opt/stack/new/nova/nova/compute/api.py", line 151, in inner
2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging     return f(self, context, instance, *args, **kw)
2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging   File "/opt/stack/new/nova/nova/compute/api.py", line 3697, in detach_volume
2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging     self._detach_volume(context, instance, volume)
2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging   File "/opt/stack/new/nova/nova/compute/api.py", line 3665, in _detach_volume
2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging     self._check_and_begin_detach(context, volume, instance)
2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging   File "/opt/stack/new/nova/nova/compute/api.py", line 3657, in _check_and_begin_detach
2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging     self.volume_api.begin_detaching(context, volume['id'])
2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging   File "/opt/stack/new/nova/nova/volume/cinder.py", line 176, in wrapper
2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging     _reraise(exception.InvalidInput(reason=err_msg))
2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging   File "/opt/stack/new/nova/nova/volume/cinder.py", line 226, in _reraise
2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging     six.reraise(type(desired_exc), desired_exc, sys.exc_info()[2])
2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging   File "/opt/stack/new/nova/nova/volume/cinder.py", line 168, in wrapper
2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging     res = method(self, ctx, *args, **kwargs)
2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging   File "/opt/stack/new/nova/nova/volume/cinder.py", line 190, in wrapper
2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging     res = method(self, ctx, volume_id, *args, **kwargs)
2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging   File "/opt/stack/new/nova/nova/volume/cinder.py", line 315, in begin_detaching
2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging     cinderclient(context).volumes.begin_detaching(volume_id)
2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging   File "/usr/local/lib/python2.7/dist-packages/cinderclient/v2/volumes.py", line 387, in begin_detaching
2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging     return self._action('os-begin_detaching', volume)
2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging   File "/usr/local/lib/python2.7/dist-packages/cinderclient/v2/volumes.py", line 334, in _action
2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging     resp, body = self.api.client.post(url, body=body)
2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging   File "/usr/local/lib/python2.7/dist-packages/cinderclient/client.py", line 167, in post
2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging     return self._cs_request(url, 'POST', **kwargs)
2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging   File "/usr/local/lib/python2.7/dist-packages/cinderclient/client.py", line 155, in _cs_request
2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging     return self.request(url, method, **kwargs)
2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging   File "/usr/local/lib/python2.7/dist-packages/cinderclient/client.py", line 144, in request
2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging     raise exceptions.from_response(resp, body)
2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging InvalidInput: Invalid input received: Invalid volume: Unable to detach volume. Volume status must be 'in-use' and attach_status must be 'attached' to detach. (HTTP 400) (Request-ID: req-328765b6-d2ce-4193-a379-dd733d0196bf)
2017-01-31 01:25:10.115 25247 ERROR nova.cells.messaging