2012-02-13 15:47:06,564 CRITICAL nova [-] Unknown connection type "None"
(nova): TRACE: Traceback (most recent call last):
(nova): TRACE:   File "/usr/bin/nova-compute", line 47, in <module>
(nova): TRACE:     server = service.Service.create(binary='nova-compute')
(nova): TRACE:   File "/usr/lib/python2.7/dist-packages/nova/service.py", line 227, in create
(nova): TRACE:     report_interval, periodic_interval)
(nova): TRACE:   File "/usr/lib/python2.7/dist-packages/nova/service.py", line 137, in __init__
(nova): TRACE:     self.manager = manager_class(host=self.host, *args, **kwargs)
(nova): TRACE:   File "/usr/lib/python2.7/dist-packages/nova/compute/manager.py", line 172, in __init__
(nova): TRACE:     utils.import_object(compute_driver),
(nova): TRACE:   File "/usr/lib/python2.7/dist-packages/nova/utils.py", line 77, in import_object
(nova): TRACE:     return cls()
(nova): TRACE:   File "/usr/lib/python2.7/dist-packages/nova/virt/connection.py", line 75, in get_connection
(nova): TRACE:     raise Exception('Unknown connection type "%s"' % t)
(nova): TRACE: Exception: Unknown connection type "None"
(nova): TRACE: