nova-compute won't restart after libvirt spawn failure

Can you include some logs? The instance creation failure, and the failure to start nova-cmpute

Unfortunately, I don't have any logs around now. This bug is reproduced easily.
You can shut off kvm, e.g. by "chmod a-rwx /dev/kvm", then any instance creation will end with failure like "hvm virtualization is not available" or smth like that.
Then restart nova-compute, it won't start raising exception somewhere in LibvirtDriver.get_info like "dom is not found".

Sorry for such vague explanation, I can provide some logs later.

I encounter the similar error when restart nova-compute, the process can not be strated:

2013-01-17 15:49:40 INFO nova.compute.manager [req-33db31ad-0456-4c21-b0fd-742cf9771e13 None None] [instance: 10085d25-056c-4856-b5ac-0806ce70ead3] Rebooting instance after nova-compute restart.
2013-01-17 15:49:40 CRITICAL nova [-] [Errno 2] No such file or directory: '/var/lib/nova/instances/instance-00000002/libvirt.xml'
2013-01-17 15:49:40 TRACE nova Traceback (most recent call last):
2013-01-17 15:49:40 TRACE nova File "/usr/bin/nova-compute", line 48, in <module>
2013-01-17 15:49:40 TRACE nova service.wait()
2013-01-17 15:49:40 TRACE nova File "/usr/lib/python2.6/site-packages/nova/service.py", line 659, in wait
2013-01-17 15:49:40 TRACE nova _launcher.wait()
2013-01-17 15:49:40 TRACE nova File "/usr/lib/python2.6/site-packages/nova/service.py", line 192, in wait
2013-01-17 15:49:40 TRACE nova super(ServiceLauncher, self).wait()
2013-01-17 15:49:40 TRACE nova File "/usr/lib/python2.6/site-packages/nova/service.py", line 162, in wait
2013-01-17 15:49:40 TRACE nova service.wait()
2013-01-17 15:49:40 TRACE nova File "/usr/lib/python2.6/site-packages/eventlet/greenthread.py", line 166, in wait
2013-01-17 15:49:40 TRACE nova return self._exit_event.wait()
2013-01-17 15:49:40 TRACE nova File "/usr/lib/python2.6/site-packages/eventlet/event.py", line 116, in wait
2013-01-17 15:49:40 TRACE nova return hubs.get_hub().switch()
2013-01-17 15:49:40 TRACE nova File "/usr/lib/python2.6/site-packages/eventlet/hubs/hub.py", line 177, in switch
2013-01-17 15:49:40 TRACE nova return self.greenlet.switch()
2013-01-17 15:49:40 TRACE nova File "/usr/lib/python2.6/site-packages/eventlet/greenthread.py", line 192, in main
2013-01-17 15:49:40 TRACE nova result = function(*args, **kwargs)
2013-01-17 15:49:40 TRACE nova File "/usr/lib/python2.6/site-packages/nova/service.py", line 132, in run_server
2013-01-17 15:49:40 TRACE nova server.start()
2013-01-17 15:49:40 TRACE nova File "/usr/lib/python2.6/site-packages/nova/service.py", line 398, in start
2013-01-17 15:49:40 TRACE nova self.manager.init_host()
2013-01-17 15:49:40 TRACE nova File "/usr/lib/python2.6/site-packages/nova/compute/manager.py", line 313, in init_host
2013-01-17 15:49:40 TRACE nova block_device_info)
2013-01-17 15:49:40 TRACE nova File "/usr/lib/python2.6/site-packages/nova/exception.py", line 117, in wrapped
2013-01-17 15:49:40 TRACE nova temp_level, payload)
2013-01-17 15:49:40 TRACE nova File "/usr/lib64/python2.6/contextlib.py", line 23, in __exit__
2013-01-17 15:49:40 TRACE nova self.gen.next()
2013-01-17 15:49:40 TRACE nova File "/usr/lib/python2.6/site-packages/nova/exception.py", line 92, in wrapped
2013-01-17 15:49:40 TRACE nova return f(*args, **kw)
2013-01-17 15:49:40 TRACE nova File "/usr/lib/python2.6/site-packages/nova/virt/libvirt/driver.py", line 981, in resume_state_on_host_boot
2013-01-17 15:49:40 TRACE nova xml = self._get_domain_xml(instance)
2013-01-17 15:49:40 TRACE nova File "/usr/lib/python2.6/site-packages/nova/virt/libvirt/driver.py", line 685, in _get_domain_xml
2013-01-17 15:49:40 TRACE...

catch the Exception when run resume_state_on_host_boot to avoid compute process exist

vish already fixed it in https://review.openstack.org/#/c/19856/