Nova cannot handle BadRequest or a Vendor Specific Exceptions

When a different process say neutron sends an exception to nova that Exception is not handled by nova and the error message is not relayed correctly to the cli.

For example;
I tried the following command failed due to a restriction:

"nova interface-attach vm --net <net-id>

Expected Result:
What was expected when this command failed was an error message as follows " VM with ports belonging to subnets across enter prises is not allowed in VSP"

Actual Result:
However, instead this message was relayed back to the cli "ERROR (ClientException): The server has either erred or is incapable of performing the requested operation. (HTTP 500) (Request-ID: req-fd69f004-591c-4ea8-b7b6-088a74cbe518)"

Nova-api logs:

The ERROR seen on nova-api is as follows:
2015-08-05 23:30:42.116 INFO oslo_messaging._drivers.impl_rabbit [req-fd69f004-591c-4ea8-b7b6-088a74cbe518 admin admin] Connected to AMQP server on 10.31.101.215:5672
2015-08-05 23:30:43.035 ERROR nova.api.openstack [req-fd69f004-591c-4ea8-b7b6-088a74cbe518 admin admin] Caught error: Remote error: BadRequest Bad request: VM with ports belonging to subnets across enter prises is not allowed in VSP
[u'Traceback (most recent call last):\n', u' File "/usr/local/lib/python2.7/dist-packages/oslo_messaging/rpc/dispatcher.py", line 142, in _dispatch_and_reply\n executor_callback))\n', u' File "/usr/
local/lib/python2.7/dist-packages/oslo_messaging/rpc/dispatcher.py", line 186, in _dispatch\n executor_callback)\n', u' File "/usr/local/lib/python2.7/dist-packages/oslo_messaging/rpc/dispatcher.py",
 line 130, in _do_dispatch\n result = func(ctxt, **new_args)\n', u' File "/opt/stack/nova/nova/compute/manager.py", line 6602, in attach_interface\n port_id, requested_ip)\n', u' File "/opt/stack
/nova/nova/compute/manager.py", line 443, in decorated_function\n return function(self, context, *args, **kwargs)\n', u' File "/opt/stack/nova/nova/exception.py", line 88, in wrapped\n payload)\n'
, u' File "/usr/local/lib/python2.7/dist-packages/oslo_utils/excutils.py", line 85, in __exit__\n ctxt.reraise = False\n', u' File "/opt/stack/nova/nova/exception.py", line 71, in wrapped\n retur
n f(self, context, *args, **kw)\n', u' File "/opt/stack/nova/nova/compute/manager.py", line 327, in decorated_function\n LOG.warning(msg, e, instance_uuid=instance_uuid)\n', u' File "/usr/local/lib/
python2.7/dist-packages/oslo_utils/excutils.py", line 85, in __exit__\n ctxt.reraise = False\n', u' File "/opt/stack/nova/nova/compute/manager.py", line 298, in decorated_function\n return function(self, context, *args, **kwargs)\n', u' File "/opt/stack/nova/nova/compute/manager.py", line 355, in decorated_function\n kwargs[\'instance\'], e, sys.exc_info())\n', u' File "/usr/local/lib/python2.7/dist-packages/oslo_utils/excutils.py", line 85, in __exit__\n ctxt.reraise = False\n', u' File "/opt/stack/nova/nova/compute/manager.py", line 343, in decorated_function\n return function(self, context, *args, **kwargs)\n', u' File "/opt/stack/nova/nova/compute/manager.py", line 5024, in attach_interface\n context, instance, port_id, network_id, requested_ip)\n', u' File "/opt/stack/nova/nova/network/neutronv2/api.py", line 705, in allocate_port_for_instance\n requested_networks=requested_networks)\n', u' File "/opt/stack/nova/nova/network/neutronv2/api.py", line 577, in allocate_for_instance\n self._delete_ports(neutron, instance, created_port_ids)\n', u' File "/usr/local/lib/python2.7/dist-packages/oslo_utils/excutils.py", line 85, in __exit__\n ctxt.reraise = False\n', u' File "/opt/stack/nova/nova/network/neutronv2/api.py", line 569, in allocate_for_instance\n security_group_ids, available_macs, dhcp_opts)\n', u' File "/opt/stack/nova/nova/network/neutronv2/api.py", line 331, in _create_port\n network_id, instance=instance)\n', u' File "/usr/local/lib/python2.7/dist-packages/oslo_utils/excutils.py", line 85, in __exit__\n ctxt.reraise = False\n', u' File "/opt/stack/nova/nova/network/neutronv2/api.py", line 304, in _create_port\n port_id = port_client.create_port(port_req_body)[\'port\'][\'id\']\n', u' File "/usr/local/lib/python2.7/dist-packages/neutronclient/v2_0/client.py", line 102, in with_params\n ret = self.function(instance, *args, **kwargs)\n', u' File "/usr/local/lib/python2.7/dist-packages/neutronclient/v2_0/client.py", line 544, in create_port\n return self.post(self.ports_path, body=body)\n', u' File "/usr/local/lib/python2.7/dist-packages/neutronclient/v2_0/client.py", line 298, in post\n headers=headers, params=params)\n', u' File "/usr/local/lib/python2.7/dist-packages/neutronclient/v2_0/client.py", line 211, in do_request\n self._handle_fault_response(status_code, replybody)\n', u' File "/usr/local/lib/python2.7/dist-packages/neutronclient/v2_0/client.py", line 185, in _handle_fault_response\n exception_handler_v20(status_code, des_error_body)\n', u' File "/usr/local/lib/python2.7/dist-packages/neutronclient/v2_0/client.py", line 70, in exception_handler_v20\n status_code=status_code)\n', u'BadRequest: Bad request: VM with ports belonging to subnets across enterprises is not allowed in VSP\n'].
2015-08-05 23:30:43.035 TRACE nova.api.openstack Traceback (most recent call last):
2015-08-05 23:30:43.035 TRACE nova.api.openstack File "/opt/stack/nova/nova/api/openstack/__init__.py", line 125, in __call__
2015-08-05 23:30:43.035 TRACE nova.api.openstack return req.get_response(self.application)
2015-08-05 23:30:43.035 TRACE nova.api.openstack File "/usr/local/lib/python2.7/dist-packages/webob/request.py", line 1317, in send
2015-08-05 23:30:43.035 TRACE nova.api.openstack application, catch_exc_info=False)
2015-08-05 23:30:43.035 TRACE nova.api.openstack File "/usr/local/lib/python2.7/dist-packages/webob/request.py", line 1281, in call_application
2015-08-05 23:30:43.035 TRACE nova.api.openstack app_iter = application(self.environ, start_response)
2015-08-05 23:30:43.035 TRACE nova.api.openstack File "/usr/local/lib/python2.7/dist-packages/webob/dec.py", line 144, in __call__
2015-08-05 23:30:43.035 TRACE nova.api.openstack return resp(environ, start_response)
2015-08-05 23:30:43.035 TRACE nova.api.openstack File "/usr/local/lib/python2.7/dist-packages/keystonemiddleware/auth_token/__init__.py", line 634, in __call__
2015-08-05 23:30:43.035 TRACE nova.api.openstack return self._call_app(env, start_response)
2015-08-05 23:30:43.035 TRACE nova.api.openstack File "/usr/local/lib/python2.7/dist-packages/keystonemiddleware/auth_token/__init__.py", line 554, in _call_app
2015-08-05 23:30:43.035 TRACE nova.api.openstack return self._app(env, _fake_start_response)
2015-08-05 23:30:43.035 TRACE nova.api.openstack File "/usr/local/lib/python2.7/dist-packages/webob/dec.py", line 144, in __call__
2015-08-05 23:30:43.035 TRACE nova.api.openstack return resp(environ, start_response)
2015-08-05 23:30:43.035 TRACE nova.api.openstack File "/usr/local/lib/python2.7/dist-packages/webob/dec.py", line 144, in __call__
2015-08-05 23:30:43.035 TRACE nova.api.openstack return resp(environ, start_response)
2015-08-05 23:30:43.035 TRACE nova.api.openstack File "/usr/local/lib/python2.7/dist-packages/routes/middleware.py", line 136, in __call__
2015-08-05 23:30:43.035 TRACE nova.api.openstack response = self.app(environ, start_response)
2015-08-05 23:30:43.035 TRACE nova.api.openstack File "/usr/local/lib/python2.7/dist-packages/webob/dec.py", line 144, in __call__
2015-08-05 23:30:43.035 TRACE nova.api.openstack return resp(environ, start_response)
2015-08-05 23:30:43.035 TRACE nova.api.openstack File "/usr/local/lib/python2.7/dist-packages/webob/dec.py", line 130, in __call__
2015-08-05 23:30:43.035 TRACE nova.api.openstack resp = self.call_func(req, *args, **self.kwargs)
2015-08-05 23:30:43.035 TRACE nova.api.openstack File "/usr/local/lib/python2.7/dist-packages/webob/dec.py", line 195, in call_func
2015-08-05 23:30:43.035 TRACE nova.api.openstack return self.func(req, *args, **kwargs)
2015-08-05 23:30:43.035 TRACE nova.api.openstack File "/opt/stack/nova/nova/api/openstack/wsgi.py", line 756, in __call__
2015-08-05 23:30:43.035 TRACE nova.api.openstack content_type, body, accept)
2015-08-05 23:30:43.035 TRACE nova.api.openstack File "/opt/stack/nova/nova/api/openstack/wsgi.py", line 821, in _process_stack
2015-08-05 23:30:43.035 TRACE nova.api.openstack action_result = self.dispatch(meth, request, action_args)
2015-08-05 23:30:43.035 TRACE nova.api.openstack File "/opt/stack/nova/nova/api/openstack/wsgi.py", line 911, in dispatch
2015-08-05 23:30:43.035 TRACE nova.api.openstack return method(req=request, **action_args)
2015-08-05 23:30:43.035 TRACE nova.api.openstack File "/opt/stack/nova/nova/api/openstack/compute/contrib/attach_interfaces.py", line 122, in create
2015-08-05 23:30:43.035 TRACE nova.api.openstack instance, network_id, port_id, req_ip)
2015-08-05 23:30:43.035 TRACE nova.api.openstack File "/opt/stack/nova/nova/compute/api.py", line 230, in wrapped
2015-08-05 23:30:43.035 TRACE nova.api.openstack return func(self, context, target, *args, **kwargs)
2015-08-05 23:30:43.035 TRACE nova.api.openstack File "/opt/stack/nova/nova/compute/api.py", line 219, in inner
2015-08-05 23:30:43.035 TRACE nova.api.openstack return function(self, context, instance, *args, **kwargs)
2015-08-05 23:30:43.035 TRACE nova.api.openstack File "/opt/stack/nova/nova/compute/api.py", line 200, in inner
2015-08-05 23:30:43.035 TRACE nova.api.openstack return f(self, context, instance, *args, **kw)
2015-08-05 23:30:43.035 TRACE nova.api.openstack File "/opt/stack/nova/nova/compute/api.py", line 3108, in attach_interface
2015-08-05 23:30:43.035 TRACE nova.api.openstack requested_ip=requested_ip)
2015-08-05 23:30:43.035 TRACE nova.api.openstack File "/opt/stack/nova/nova/compute/rpcapi.py", line 355, in attach_interface
2015-08-05 23:30:43.035 TRACE nova.api.openstack port_id=port_id, requested_ip=requested_ip)
2015-08-05 23:30:43.035 TRACE nova.api.openstack File "/usr/local/lib/python2.7/dist-packages/oslo_messaging/rpc/client.py", line 156, in call
2015-08-05 23:30:43.035 TRACE nova.api.openstack retry=self.retry)
2015-08-05 23:30:43.035 TRACE nova.api.openstack File "/usr/local/lib/python2.7/dist-packages/oslo_messaging/transport.py", line 90, in _send
2015-08-05 23:30:43.035 TRACE nova.api.openstack timeout=timeout, retry=retry)
2015-08-05 23:30:43.035 TRACE nova.api.openstack File "/usr/local/lib/python2.7/dist-packages/oslo_messaging/_drivers/amqpdriver.py", line 350, in send
2015-08-05 23:30:43.035 TRACE nova.api.openstack retry=retry)
2015-08-05 23:30:43.035 TRACE nova.api.openstack File "/usr/local/lib/python2.7/dist-packages/oslo_messaging/_drivers/amqpdriver.py", line 341, in _send
2015-08-05 23:30:43.035 TRACE nova.api.openstack raise result
2015-08-05 23:30:43.035 TRACE nova.api.openstack RemoteError: Remote error: BadRequest Bad request: VM with ports belonging to subnets across enterprises is not allowed in VSP
2015-08-05 23:30:43.035 TRACE nova.api.openstack [u'Traceback (most recent call last):\n', u' File "/usr/local/lib/python2.7/dist-packages/oslo_messaging/rpc/dispatcher.py", line 142, in _dispatch_and_reply\n executor_callback))\n', u' File "/usr/local/lib/python2.7/dist-packages/oslo_messaging/rpc/dispatcher.py", line 186, in _dispatch\n executor_callback)\n', u' File "/usr/local/lib/python2.7/dist-packages/oslo_messaging/rpc/dispatcher.py", line 130, in _do_dispatch\n result = func(ctxt, **new_args)\n', u' File "/opt/stack/nova/nova/compute/manager.py", line 6602, in attach_interface\n port_id, requested_ip)\n', u' File "/opt/stack/nova/nova/compute/manager.py", line 443, in decorated_function\n return function(self, context, *args, **kwargs)\n', u' File "/opt/stack/nova/nova/exception.py", line 88, in wrapped\n payload)\n', u' File "/usr/local/lib/python2.7/dist-packages/oslo_utils/excutils.py", line 85, in __exit__\n ctxt.reraise = False\n', u' File "/opt/stack/nova/nova/exception.py", line 71, in wrapped\n return f(self, context, *args, **kw)\n', u' File "/opt/stack/nova/nova/compute/manager.py", line 327, in decorated_function\n LOG.warning(msg, e, instance_uuid=instance_uuid)\n', u' File "/usr/local/lib/python2.7/dist-packages/oslo_utils/excutils.py", line 85, in __exit__\n ctxt.reraise = False\n', u' File "/opt/stack/nova/nova/compute/manager.py", line 298, in decorated_function\n return function(self, context, *args, **kwargs)\n', u' File "/opt/stack/nova/nova/compute/manager.py", line 355, in decorated_function\n kwargs[\'instance\'], e, sys.exc_info())\n', u' File "/usr/local/lib/python2.7/dist-packages/oslo_utils/excutils.py", line 85, in __exit__\n ctxt.reraise = False\n', u' File "/opt/stack/nova/nova/compute/manager.py", line 343, in decorated_function\n return function(self, context, *args, **kwargs)\n', u' File "/opt/stack/nova/nova/compute/manager.py", line 5024, in attach_interface\n context, instance, port_id, network_id, requested_ip)\n', u' File "/opt/stack/nova/nova/network/neutronv2/api.py", line 705, in allocate_port_for_instance\n requested_networks=requested_networks)\n', u' File "/opt/stack/nova/nova/network/neutronv2/api.py", line 577, in allocate_for_instance\n self._delete_ports(neutron, instance, created_port_ids)\n', u' File "/usr/local/lib/python2.7/dist-packages/oslo_utils/excutils.py", line 85, in __exit__\n ctxt.reraise = False\n', u' File "/opt/stack/nova/nova/network/neutronv2/api.py", line 569, in allocate_for_instance\n security_group_ids, available_macs, dhcp_opts)\n', u' File "/opt/stack/nova/nova/network/neutronv2/api.py", line 331, in _create_port\n network_id, instance=instance)\n', u' File "/usr/local/lib/python2.7/dist-packages/oslo_utils/excutils.py", line 85, in __exit__\n ctxt.reraise = False\n', u' File "/opt/stack/nova/nova/network/neutronv2/api.py", line 304, in _create_port\n port_id = port_client.create_port(port_req_body)[\'port\'][\'id\']\n', u' File "/usr/local/lib/python2.7/dist-packages/neutronclient/v2_0/client.py", line 102, in with_params\n ret = self.function(instance, *args, **kwargs)\n', u' File "/usr/local/lib/python2.7/dist-packages/neutronclient/v2_0/client.py", line 544, in create_port\n return self.post(self.ports_path, body=body)\n', u' File "/usr/local/lib/python2.7/dist-packages/neutronclient/v2_0/client.py", line 298, in post\n headers=headers, params=params)\n', u' File "/usr/local/lib/python2.7/dist-packages/neutronclient/v2_0/client.py", line 211, in do_request\n self._handle_fault_response(status_code, replybody)\n', u' File "/usr/local/lib/python2.7/dist-packages/neutronclient/v2_0/client.py", line 185, in _handle_fault_response\n exception_handler_v20(status_code, des_error_body)\n', u' File "/usr/local/lib/python2.7/dist-packages/neutronclient/v2_0/client.py", line 70, in exception_handler_v20\n status_code=status_code)\n', u'BadRequest: Bad request: VM with ports belonging to subnets across enterprises is not allowed in VSP\n'].