I am encountering a similar failure on a single server devstack setup on Ubuntu. I don’t see an error in keystone.log. Attaching logs and configs.

=== key.log (last lines):
…
2016-04-07 12:38:26.217 14348 DEBUG keystone.policy.backends.rules [req-b03c8491-5591-433b-a79a-d0210d303787 12cbf8c425e64bd49336482ca6717802 19fec374ca7347cb8772fe1a9a549b56 - default default] enforce identity:validate_token
: {'is_delegated_auth': False, 'access_token_id': None, 'user_id': u'12cbf8c425e64bd49336482ca6717802', 'roles': [u'service'], 'user_domain_id': u'default', 'trustee_id': None, 'trustor_id': None, 'consumer_id': None, 'token'
: <KeystoneToken (audit_id=r10GJXEMT768UYY8GUVuVA, audit_chain_id=r10GJXEMT768UYY8GUVuVA) at 0x7f161e7ad618>, 'project_id': u'19fec374ca7347cb8772fe1a9a549b56', 'trust_id': None, 'project_domain_id': u'default'} 2016-04-07 12
:38:26.217 enforce /opt/stack/keystone/keystone/policy/backends/rules.py:76
2016-04-07 12:38:26.218 14348 DEBUG keystone.common.controller [req-b03c8491-5591-433b-a79a-d0210d303787 12cbf8c425e64bd49336482ca6717802 19fec374ca7347cb8772fe1a9a549b56 - default default] RBAC: Authorization granted 2016-04
-07 12:38:26.218 inner /opt/stack/keystone/keystone/common/controller.py:180


=== nova.log:
2016-04-07 12:38:25.154 DEBUG keystoneauth.session [req-62c3900e-926c-44ec-a9d0-d3aafa68359d admin demo] REQ: curl -g -i -X GET http://172.18.3.86:9696/v2.0/ports.json?fields=id&tenant_id=44989b6d94ab4468b8c27dc730a7e9e4 -H $
2016-04-07 12:38:25.416 DEBUG keystoneauth.session [req-62c3900e-926c-44ec-a9d0-d3aafa68359d admin demo] RESP: [200] Date: Thu, 07 Apr 2016 09:38:25 GMT Connection: keep-alive Content-Type: application/json; charset=UTF-8 Co$
RESP BODY: {"ports": [{"id": "b983aef5-9c96-40f7-b209-ea40e6c8f73d"}, {"id": "d7bf4ace-c4a5-42d8-8a81-aa9fdbd65678"}, {"id": "e91a6d11-c89a-41ef-882f-95e19697b5b6"}]}
 from (pid=12448) _http_log_response /usr/local/lib/python2.7/dist-packages/keystoneauth1/session.py:277
2016-04-07 12:38:26.410 ERROR nova.api.openstack.extensions [req-62c3900e-926c-44ec-a9d0-d3aafa68359d admin demo] Unexpected exception in API method
2016-04-07 12:38:26.410 TRACE nova.api.openstack.extensions Traceback (most recent call last):
2016-04-07 12:38:26.410 TRACE nova.api.openstack.extensions   File "/opt/stack/nova/nova/api/openstack/extensions.py", line 478, in wrapped
2016-04-07 12:38:26.410 TRACE nova.api.openstack.extensions     return f(*args, **kwargs)
2016-04-07 12:38:26.410 TRACE nova.api.openstack.extensions   File "/opt/stack/nova/nova/api/validation/__init__.py", line 73, in wrapper
2016-04-07 12:38:26.410 TRACE nova.api.openstack.extensions     return func(*args, **kwargs)
2016-04-07 12:38:26.410 TRACE nova.api.openstack.extensions   File "/opt/stack/nova/nova/api/validation/__init__.py", line 73, in wrapper
2016-04-07 12:38:26.410 TRACE nova.api.openstack.extensions     return func(*args, **kwargs)
2016-04-07 12:38:26.410 TRACE nova.api.openstack.extensions   File "/opt/stack/nova/nova/api/validation/__init__.py", line 73, in wrapper
2016-04-07 12:38:26.410 TRACE nova.api.openstack.extensions     return func(*args, **kwargs)
2016-04-07 12:38:26.410 TRACE nova.api.openstack.extensions   File "/opt/stack/nova/nova/api/openstack/compute/servers.py", line 629, in create
2016-04-07 12:38:26.410 TRACE nova.api.openstack.extensions     **create_kwargs)
2016-04-07 12:38:26.410 TRACE nova.api.openstack.extensions   File "/opt/stack/nova/nova/hooks.py", line 154, in inner
2016-04-07 12:38:26.410 TRACE nova.api.openstack.extensions     rv = f(*args, **kwargs)
2016-04-07 12:38:26.410 TRACE nova.api.openstack.extensions   File "/opt/stack/nova/nova/compute/api.py", line 1556, in create
2016-04-07 12:38:26.410 TRACE nova.api.openstack.extensions     check_server_group_quota=check_server_group_quota)
2016-04-07 12:38:26.410 TRACE nova.api.openstack.extensions   File "/opt/stack/nova/nova/compute/api.py", line 1155, in _create_instance
2016-04-07 12:38:26.410 TRACE nova.api.openstack.extensions     block_device_mapping, legacy_bdm)
2016-04-07 12:38:26.410 TRACE nova.api.openstack.extensions   File "/opt/stack/nova/nova/compute/api.py", line 782, in _check_and_transform_bdm
2016-04-07 12:38:26.410 TRACE nova.api.openstack.extensions     context, block_device_mapping)
2016-04-07 12:38:26.410 TRACE nova.api.openstack.extensions   File "/opt/stack/nova/nova/objects/block_device.py", line 382, in block_device_make_list_from_dicts
2016-04-07 12:38:26.410 TRACE nova.api.openstack.extensions     for bdm in bdm_dicts_list]
2016-04-07 12:38:26.410 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/oslo_versionedobjects/base.py", line 304, in __init__
2016-04-07 12:38:26.410 TRACE nova.api.openstack.extensions     setattr(self, key, kwargs[key])
2016-04-07 12:38:26.410 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/oslo_versionedobjects/base.py", line 72, in setter
2016-04-07 12:38:26.410 TRACE nova.api.openstack.extensions     field_value = field.coerce(self, name, value)
2016-04-07 12:38:26.410 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/oslo_versionedobjects/fields.py", line 192, in coerce
2016-04-07 12:38:26.410 TRACE nova.api.openstack.extensions     return self._type.coerce(obj, attr, value)
2016-04-07 12:38:26.410 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/oslo_versionedobjects/fields.py", line 297, in coerce
2016-04-07 12:38:26.410 TRACE nova.api.openstack.extensions     raise ValueError(msg)
2016-04-07 12:38:26.410 TRACE nova.api.openstack.extensions ValueError: Field value volumef51271c3-068b-44c3-b6c4-2b1e13b303a0 is invalid
2016-04-07 12:38:26.410 TRACE nova.api.openstack.extensions 
2016-04-07 12:38:26.412 INFO nova.api.openstack.wsgi [req-62c3900e-926c-44ec-a9d0-d3aafa68359d admin demo] HTTP exception thrown: Unexpected API Error. Please report this at http://bugs.launchpad.net/nova/ and attach the Nov$
<type 'exceptions.ValueError'>