Hello! 1 engine- not hosted FC 19 + ovirt 3.5 ; 3 nodes - F20 and ovirt 3.5 patternfly due to high vdsm memory usage. All theree nodes serves as glusterfs server - 3 replicated bricks. After putting DC in maintenance - all VM shutdown, storages in maintenance (ISO, Data, Export) , stop gluster volume and finally hosts in maintenance , runned "yum update" on all nodes, reboot them, "Confirm host has been rebooted" but trying to activate them raise "Gluster command [<UNKNOWN>] failed on server....." and hosts goes in non operational. vdsm log goes like: Thread-15::ERROR::2014-12-18 10:17:53,439::__init__::493::jsonrpc.JsonRpcServer::(_serveRequest) Internal server error Traceback (most recent call last): File "/usr/lib/python2.7/site-packages/yajsonrpc/__init__.py", line 488, in _serveRequest res = method(**params) File "/usr/share/vdsm/rpc/Bridge.py", line 264, in _dynamicMethod result = fn(*methodArgs) File "/usr/share/vdsm/gluster/apiwrapper.py", line 79, in list return self._gluster.hostsList() File "/usr/share/vdsm/gluster/api.py", line 54, in wrapper rv = func(*args, **kwargs) File "/usr/share/vdsm/gluster/api.py", line 251, in hostsList return {'hosts': self.svdsmProxy.glusterPeerStatus()} File "/usr/share/vdsm/supervdsm.py", line 50, in __call__ return callMethod() File "/usr/share/vdsm/supervdsm.py", line 48, in <lambda> **kwargs) File "<string>", line 2, in glusterPeerStatus File "/usr/lib64/python2.7/multiprocessing/managers.py", line 773, in _callmethod raise convert_to_error(kind, result) GlusterCmdExecFailedException: Command execution failed error: Connection failed. Please check if gluster daemon is operational. return code: 1 *NB* *Reinstalling all host after moving in Maintenance from Non-op avtivates them and I am able to start gluster volume, activate stoarage domains and so on.......* <https://bugzilla.redhat.com/show_bug.cgi?id=1142647>