Hi,

After reboot my Hypervisior host can not activate again in the cluster and failed with the following error :- 

Gluster command [<UNKNOWN>] failed on server...

Engine logs :- 

2014-11-24 18:05:28,397 INFO  [org.ovirt.engine.core.vdsbroker.gluster.GlusterVolumesListVDSCommand] (DefaultQuartzScheduler_Worker-64) START, GlusterVolumesListVDSCommand(HostName = Compute4, HostId = 33648a90-200c-45ca-89d5-1ce305d79a6a), log id: 5f251c90
2014-11-24 18:05:30,609 INFO  [org.ovirt.engine.core.vdsbroker.gluster.GlusterVolumesListVDSCommand] (DefaultQuartzScheduler_Worker-64) FINISH, GlusterVolumesListVDSCommand, return: {26ae1672-ee09-4a38-8fd2-72dd9974cc2b=org.ovirt.engine.core.common.businessentities.gluster.GlusterVolumeEntity@d95203e0}, log id: 5f251c90
2014-11-24 18:05:33,768 INFO  [org.ovirt.engine.core.bll.ActivateVdsCommand] (ajp--127.0.0.1-8702-8) [287d570d] Lock Acquired to object EngineLock [exclusiveLocks= key: 0bf6b00f-7947-4411-b55a-cc5eea2b381a value: VDS
, sharedLocks= ]
2014-11-24 18:05:33,795 INFO  [org.ovirt.engine.core.bll.ActivateVdsCommand] (org.ovirt.thread.pool-8-thread-45) [287d570d] Running command: ActivateVdsCommand internal: false. Entities affected :  ID: 0bf6b00f-7947-4411-b55a-cc5eea2b381a Type: VDSAction group MANIPULATE_HOST with role type ADMIN
2014-11-24 18:05:33,796 INFO  [org.ovirt.engine.core.bll.ActivateVdsCommand] (org.ovirt.thread.pool-8-thread-45) [287d570d] Before acquiring lock in order to prevent monitoring for host Compute5 from data-center SV_WTC
2014-11-24 18:05:33,797 INFO  [org.ovirt.engine.core.bll.ActivateVdsCommand] (org.ovirt.thread.pool-8-thread-45) [287d570d] Lock acquired, from now a monitoring of host will be skipped for host Compute5 from data-center SV_WTC
2014-11-24 18:05:33,817 INFO  [org.ovirt.engine.core.vdsbroker.SetVdsStatusVDSCommand] (org.ovirt.thread.pool-8-thread-45) [287d570d] START, SetVdsStatusVDSCommand(HostName = Compute5, HostId = 0bf6b00f-7947-4411-b55a-cc5eea2b381a, status=Unassigned, nonOperationalReason=NONE, stopSpmFailureLogged=false), log id: 1cbc7311
2014-11-24 18:05:33,820 INFO  [org.ovirt.engine.core.vdsbroker.SetVdsStatusVDSCommand] (org.ovirt.thread.pool-8-thread-45) [287d570d] FINISH, SetVdsStatusVDSCommand, log id: 1cbc7311
2014-11-24 18:05:34,086 INFO  [org.ovirt.engine.core.bll.ActivateVdsCommand] (org.ovirt.thread.pool-8-thread-45) Activate finished. Lock released. Monitoring can run now for host Compute5 from data-center SV_WTC
2014-11-24 18:05:34,088 INFO  [org.ovirt.engine.core.dal.dbbroker.auditloghandling.AuditLogDirector] (org.ovirt.thread.pool-8-thread-45) Correlation ID: 287d570d, Job ID: 5ef8e4d6-b2bc-469e-8e81-7ef74b2a001a, Call Stack: null, Custom Event ID: -1, Message: Host Compute5 was activated by admin.
2014-11-24 18:05:34,090 INFO  [org.ovirt.engine.core.bll.ActivateVdsCommand] (org.ovirt.thread.pool-8-thread-45) Lock freed to object EngineLock [exclusiveLocks= key: 0bf6b00f-7947-4411-b55a-cc5eea2b381a value: VDS
, sharedLocks= ]
2014-11-24 18:05:35,792 INFO  [org.ovirt.engine.core.vdsbroker.gluster.GlusterVolumesListVDSCommand] (DefaultQuartzScheduler_Worker-55) [3706e836] START, GlusterVolumesListVDSCommand(HostName = Compute4, HostId = 33648a90-200c-45ca-89d5-1ce305d79a6a), log id: 48a0c832
2014-11-24 18:05:37,064 INFO  [org.ovirt.engine.core.vdsbroker.vdsbroker.GetHardwareInfoVDSCommand] (DefaultQuartzScheduler_Worker-69) START, GetHardwareInfoVDSCommand(HostName = Compute5, HostId = 0bf6b00f-7947-4411-b55a-cc5eea2b381a, vds=Host[Compute5,0bf6b00f-7947-4411-b55a-cc5eea2b381a]), log id: 6d560cc2
2014-11-24 18:05:37,074 INFO  [org.ovirt.engine.core.vdsbroker.vdsbroker.GetHardwareInfoVDSCommand] (DefaultQuartzScheduler_Worker-69) FINISH, GetHardwareInfoVDSCommand, log id: 6d560cc2
2014-11-24 18:05:37,093 WARN  [org.ovirt.engine.core.vdsbroker.VdsManager] (DefaultQuartzScheduler_Worker-69) Host Compute5 is running with disabled SELinux.
2014-11-24 18:05:37,127 INFO  [org.ovirt.engine.core.bll.HandleVdsCpuFlagsOrClusterChangedCommand] (DefaultQuartzScheduler_Worker-69) [2b4a51cf] Running command: HandleVdsCpuFlagsOrClusterChangedCommand internal: true. Entities affected :  ID: 0bf6b00f-7947-4411-b55a-cc5eea2b381a Type: VDS
2014-11-24 18:05:37,147 INFO  [org.ovirt.engine.core.vdsbroker.gluster.GlusterServersListVDSCommand] (DefaultQuartzScheduler_Worker-69) [2b4a51cf] START, GlusterServersListVDSCommand(HostName = Compute5, HostId = 0bf6b00f-7947-4411-b55a-cc5eea2b381a), log id: 4faed87
2014-11-24 18:05:37,164 INFO  [org.ovirt.engine.core.vdsbroker.gluster.GlusterServersListVDSCommand] (DefaultQuartzScheduler_Worker-69) [2b4a51cf] FINISH, GlusterServersListVDSCommand, log id: 4faed87
2014-11-24 18:05:37,189 INFO  [org.ovirt.engine.core.bll.SetNonOperationalVdsCommand] (DefaultQuartzScheduler_Worker-69) [4a84c4e5] Running command: SetNonOperationalVdsCommand internal: true. Entities affected :  ID: 0bf6b00f-7947-4411-b55a-cc5eea2b381a Type: VDS
2014-11-24 18:05:37,206 INFO  [org.ovirt.engine.core.vdsbroker.SetVdsStatusVDSCommand] (DefaultQuartzScheduler_Worker-69) [4a84c4e5] START, SetVdsStatusVDSCommand(HostName = Compute5, HostId = 0bf6b00f-7947-4411-b55a-cc5eea2b381a, status=NonOperational, nonOperationalReason=GLUSTER_COMMAND_FAILED, stopSpmFailureLogged=false), log id: fed5617
2014-11-24 18:05:37,209 INFO  [org.ovirt.engine.core.vdsbroker.SetVdsStatusVDSCommand] (DefaultQuartzScheduler_Worker-69) [4a84c4e5] FINISH, SetVdsStatusVDSCommand, log id: fed5617
2014-11-24 18:05:37,223 ERROR [org.ovirt.engine.core.dal.dbbroker.auditloghandling.AuditLogDirector] (DefaultQuartzScheduler_Worker-69) [4a84c4e5] Correlation ID: 4a84c4e5, Job ID: 4bfd4a6d-c3ef-468f-a40e-a3a6ca13011b, Call Stack: null, Custom Event ID: -1, Message: Gluster command [<UNKNOWN>] failed on server Compute5.
2014-11-24 18:05:37,243 INFO  [org.ovirt.engine.core.dal.dbbroker.auditloghandling.AuditLogDirector] (DefaultQuartzScheduler_Worker-69) [4a84c4e5] Correlation ID: null, Call Stack: null, Custom Event ID: -1, Message: Status of host Compute5 was set to NonOperational.
2014-11-24 18:05:37,272 INFO  [org.ovirt.engine.core.bll.HandleVdsVersionCommand] (DefaultQuartzScheduler_Worker-69) [a0c8a7f] Running command: HandleVdsVersionCommand internal: true. Entities affected :  ID: 0bf6b00f-7947-4411-b55a-cc5eea2b381a Type: VDS
2014-11-24 18:05:37,274 INFO  [org.ovirt.engine.core.vdsbroker.VdsUpdateRunTimeInfo] (DefaultQuartzScheduler_Worker-69) [a0c8a7f] Host 0bf6b00f-7947-4411-b55a-cc5eea2b381a : Compute5 is already in NonOperational status for reason GLUSTER_COMMAND_FAILED. SetNonOperationalVds command is skipped.
2014-11-24 18:05:38,065 INFO  [org.ovirt.engine.core.vdsbroker.gluster.GlusterVolumesListVDSCommand] (DefaultQuartzScheduler_Worker-55) [3706e836] FINISH, GlusterVolumesListVDSCommand, return: {26ae1672-ee09-4a38-8fd2-72dd9974cc2b=org.ovirt.engine.core.common.businessentities.gluster.GlusterVolumeEntity@4e72a1b1}, log id: 48a0c832
2014-11-24 18:05:43,243 INFO  [org.ovirt.engine.core.vdsbroker.gluster.GlusterVolumesListVDSCommand] (DefaultQuartzScheduler_Worker-35) START, GlusterVolumesListVDSCommand(HostName = Compute4, HostId = 33648a90-200c-45ca-89d5-1ce305d79a6a), log id: 3ce13ebc
^C
[root@ccr01 ~]#

Thanks,
Punit