I got an error when trying to migrate a VM.
On the "events" tab on the bottom it said.
In the engine log it says the following.
2013-02-05 22:09:24,606 ERROR [org.ovirt.engine.core.vdsbroker.VdsUpdateRunTimeInfo] (QuartzScheduler_Worker-66) Rerun vm 6a9178cc-56cf-42f3-8a4c-098095d737f9. Called from vds VR2
2013-02-05 22:09:24,611 INFO [org.ovirt.engine.core.vdsbroker.vdsbroker.MigrateStatusVDSCommand] (pool-3-thread-48) START, MigrateStatusVDSCommand(HostName = VR2, HostId = 153b2742-6f2f-11e2-a248-52540038c812, vmId=6a9178cc-56cf-42f3-8a4c-098095d737f9), log id: 38675c5e
2013-02-05 22:09:24,656 ERROR [org.ovirt.engine.core.vdsbroker.vdsbroker.BrokerCommandBase] (pool-3-thread-48) Failed in MigrateStatusVDS method
2013-02-05 22:09:24,657 ERROR [org.ovirt.engine.core.vdsbroker.vdsbroker.BrokerCommandBase] (pool-3-thread-48) Error code noConPeer and error message VDSGenericException: VDSErrorException: Failed to MigrateStatusVDS, error = Could not connect to peer VDS
2013-02-05 22:09:24,662 INFO [org.ovirt.engine.core.vdsbroker.vdsbroker.BrokerCommandBase] (pool-3-thread-48) Command org.ovirt.engine.core.vdsbroker.vdsbroker.MigrateStatusVDSCommand return value
Class Name: org.ovirt.engine.core.vdsbroker.vdsbroker.StatusOnlyReturnForXmlRpc
mStatus Class Name: org.ovirt.engine.core.vdsbroker.vdsbroker.StatusForXmlRpc
mMessage Could not connect to peer VDS
2013-02-05 22:09:24,663 INFO [org.ovirt.engine.core.vdsbroker.vdsbroker.BrokerCommandBase] (pool-3-thread-48) HostName = VR2
2013-02-05 22:09:24,664 ERROR [org.ovirt.engine.core.vdsbroker.VDSCommandBase] (pool-3-thread-48) Command MigrateStatusVDS execution failed. Exception: VDSErrorException: VDSGenericException: VDSErrorException: Failed to MigrateStatusVDS, error = Could not connect to peer VDS
2013-02-05 22:09:24,664 INFO [org.ovirt.engine.core.vdsbroker.vdsbroker.MigrateStatusVDSCommand] (pool-3-thread-48) FINISH, MigrateStatusVDSCommand, log id: 38675c5e