[...]
2011-12-05 13:57:56,644 DEBUG nova.virt.libvirt.firewall [-] The nwfilter(nova-instance-instance-00000006-secgroup) for instance-0000000
6 is not found. from (pid=853) unfilter_instance /usr/lib/python2.7/dist-packages/nova/virt/libvirt/firewall.py:320
2011-12-05 13:57:56,645 INFO nova.virt.libvirt_conn [-] instance instance-00000006: deleting instance files /var/lib/nova/instances/instance-00000006
2011-12-05 13:57:56,646 DEBUG nova.utils [-] Running cmd (subprocess): sudo mount from (pid=853) execute /usr/lib/python2.7/dist-packages/nova/utils.py:168
2011-12-05 13:57:56,664 DEBUG nova.utils [-] Running cmd (subprocess): sudo umount /var/lib/nova/instances/instance-00000006/rootfs from (pid=853) execute /usr/lib/python2.7/dist-packages/nova/utils.py:168
2011-12-05 13:57:56,691 DEBUG nova.utils [-] Running cmd (subprocess): sudo qemu-nbd -d /dev/nbd15 from (pid=853) execute /usr/lib/python2.7/dist-packages/nova/utils.py:168
2011-12-05 13:57:56,765 ERROR nova.exception [-] Uncaught exception
(nova.exception): TRACE: Traceback (most recent call last):
(nova.exception): TRACE:   File "/usr/lib/python2.7/dist-packages/nova/exception.py", line 98, in wrapped
(nova.exception): TRACE:     return f(*args, **kw)
(nova.exception): TRACE:   File "/usr/lib/python2.7/dist-packages/nova/compute/manager.py", line 117, in decorated_function
(nova.exception): TRACE:     function(self, context, instance_id, *args, **kwargs)
(nova.exception): TRACE:   File "/usr/lib/python2.7/dist-packages/nova/compute/manager.py", line 493, in terminate_instance
(nova.exception): TRACE:     self._shutdown_instance(context, instance_id, 'Terminating')
(nova.exception): TRACE:   File "/usr/lib/python2.7/dist-packages/nova/compute/manager.py", line 484, in _shutdown_instance
(nova.exception): TRACE:     self.driver.destroy(instance, network_info)
(nova.exception): TRACE:   File "/usr/lib/python2.7/dist-packages/nova/virt/libvirt/connection.py", line 401, in destroy
(nova.exception): TRACE:     self._cleanup(instance)
(nova.exception): TRACE:   File "/usr/lib/python2.7/dist-packages/nova/virt/libvirt/connection.py", line 414, in _cleanup
(nova.exception): TRACE:     shutil.rmtree(target)
(nova.exception): TRACE:   File "/usr/lib/python2.7/shutil.py", line 244, in rmtree
(nova.exception): TRACE:     rmtree(fullname, ignore_errors, onerror)
(nova.exception): TRACE:   File "/usr/lib/python2.7/shutil.py", line 253, in rmtree
(nova.exception): TRACE:     onerror(os.rmdir, path, sys.exc_info())
(nova.exception): TRACE:   File "/usr/lib/python2.7/shutil.py", line 251, in rmtree
(nova.exception): TRACE:     os.rmdir(path)
(nova.exception): TRACE: OSError: [Errno 16] Device or resource busy: '/var/lib/nova/instances/instance-00000006/rootfs'
(nova.exception): TRACE: 
2011-12-05 13:57:56,766 ERROR nova.rpc [-] Exception during message handling
(nova.rpc): TRACE: Traceback (most recent call last):
(nova.rpc): TRACE:   File "/usr/lib/python2.7/dist-packages/nova/rpc/impl_kombu.py", line 620, in _process_data
(nova.rpc): TRACE:     rval = node_func(context=ctxt, **node_args)
(nova.rpc): TRACE:   File "/usr/lib/python2.7/dist-packages/nova/exception.py", line 129, in wrapped
(nova.rpc): TRACE:     raise Error(str(e))
(nova.rpc): TRACE: Error: [Errno 16] Device or resource busy: '/var/lib/nova/instances/instance-00000006/rootfs'
(nova.rpc): TRACE: 
[...]