ERROR: Failed to attach interface (HTTP 500) (Request-ID: req-XXXX)

Question

I have launched an instance with only one interface.When I tried to attach an additional interface to running instance I'm getting this error. Any idea?

I'm using Neutron network. Also Additional interface and existing interface are on different network. I'm using Icehouse on Ubuntu 14.

nova interface-attach --net-id XXXX 
--fixed-ip 192.168.1.246 Test_a5

ERROR: Failed to attach interface (HTTP 500) (Request-ID: req-XXX)

I got this error form nova-compute.log

ERROR nova.virt.libvirt.driver [req-XXXX XXXX] [instance: XXXX] 
attaching network adapter failed.



ERROR oslo.messaging.rpc.dispatcher [-] Exception during message handling: <nova.objects.instance.Instance object at 0x7f0b40525850>
TRACE oslo.messaging.rpc.dispatcher Traceback (most recent call last):
TRACE oslo.messaging.rpc.dispatcher   File "/usr/lib/python2.7/dist-packages/oslo/messaging/rpc/dispatcher.py", line 133, in _dispatch_and_reply
TRACE oslo.messaging.rpc.dispatcher     incoming.message))
TRACE oslo.messaging.rpc.dispatcher   File "/usr/lib/python2.7/dist-packages/oslo/messaging/rpc/dispatcher.py", line 176, in _dispatch
TRACE oslo.messaging.rpc.dispatcher     return self._do_dispatch(endpoint, method, ctxt, args)
TRACE oslo.messaging.rpc.dispatcher   File "/usr/lib/python2.7/dist-packages/oslo/messaging/rpc/dispatcher.py", line 122, in _do_dispatch
TRACE oslo.messaging.rpc.dispatcher     result = getattr(endpoint, method)(ctxt, **new_args)
TRACE oslo.messaging.rpc.dispatcher   File "/usr/lib/python2.7/dist-packages/nova/compute/manager.py", line 399, in decorated_function
TRACE oslo.messaging.rpc.dispatcher     return function(self, context, *args, **kwargs)
TRACE oslo.messaging.rpc.dispatcher   File "/usr/lib/python2.7/dist-packages/nova/compute/manager.py", line 4356, in attach_interface
TRACE oslo.messaging.rpc.dispatcher     self.driver.attach_interface(instance, image_meta, network_info[0])
TRACE oslo.messaging.rpc.dispatcher   File "/usr/lib/python2.7/dist-packages/nova/virt/libvirt/driver.py", line 1410, in attach_interface
TRACE oslo.messaging.rpc.dispatcher     raise exception.InterfaceAttachFailed(instance)
TRACE oslo.messaging.rpc.dispatcher InterfaceAttachFailed: <nova.objects.instance.Instance object at 0x7f0b40525850>
TRACE oslo.messaging.rpc.dispatcher 
ERROR oslo.messaging._drivers.common [-] Returning exception <nova.objects.instance.Instance object at 0x7f0b40525850> to caller
ERROR oslo.messaging._drivers.common [-] ['Traceback (most 

---

`recent call last):\n', '  File "/usr/lib/python2.7/dist-packages/oslo/messaging/rpc/dispatcher.py", line 133, in _dispatch_and_reply\n  
incoming.message))\n', '  File "/usr/lib/python2.7/dist-packages/oslo/messaging/rpc/dispatcher.py", line 176, in _dispatch\n    
return self._do_dispatch(endpoint, method, ctxt, args)\n', '  File "/usr/lib/python2.7/dist-packages/oslo/messaging/rpc/dispatcher.py", line 122, in _do_dispatch\n    
result = getattr(endpoint, method)(ctxt, **new_args)\n', '  File "/usr/lib/python2.7/dist-packages/nova/compute/manager.py", line 399, in decorated_function\n 
return function(self, context, *args, **kwargs)\n', '  File "/usr/lib/python2.7/dist-packages/nova/compute/manager.py", line 4356, in attach_interface\n  
self.driver.attach_interface(instance, image_meta, network_info[0])\n',
'  File` "/usr/lib/python2.7/dist-packages/nova/virt/libvirt/driver.py", line 1410, in attach_interface\n    raise exception.InterfaceAttachFailed(instance)\n',
'InterfaceAttachFailed: <nova.objects.instance.Instance object at 0x7f0b40525850>\n']