[ovirt-users] VMs changing to unknown state

I have an ovirt host running ovirt 4.0 which keeps putting the VMs running on that host into an unknown state. I checked the vdsm logs and there are several errors similar to below. Mar 20 10:16:11 ovirt-node-production3.example.com vdsm[17123]: vdsm root ERROR Unhandled exception Traceback (most recent call last): File "/usr/lib/python2.7/site-packages/vdsm/utils.py", line 372, in wrapper return f(*a, **kw) File "/usr/share/vdsm/virt/migration.py", line 624, in run self.monitor_migration() File "/usr/share/vdsm/virt/migration.py", line 657, in monitor_migration job_stats = self._vm._dom.jobStats() File "/usr/lib/python2.7/site-packages/vdsm/virt/virdomain.py", line 69, in f ret = attr(*args, **kwargs) File "/usr/lib/python2.7/site-packages/vdsm/libvirtconnection.py", line 123, in wrapper ret = f(*args, **kwargs) File "/usr/lib/python2.7/site-packages/vdsm/utils.py", line 917, in wrapper return func(inst, *args, **kwargs) File "/usr/lib64/python2.7/site-packages/libvirt.py", line 1387, in jobStats if ret is None: raise libvirtError ('virDomainGetJobStats() failed', dom=self) libvirtError: Requested operation is not valid: domain is not running Restarting vdsmd resolves the issue however I would like to resolve the issue permanently. Does anybody know what would cause this?