Hi Ruifang, It is not clear to me if you verified that leader1 restarted correctly. Was it able to join the ensemble by following leader2?-FlavioOn Nov 1, 2010, at 8:09 PM, Ruifang Ge wrote:Hi,I started a 5-node zookeeper cluster, then killed the leader (leader1). One of the other server became the new leader(leader2). After that, I restarted the former leader (leader1), and it failed to be connected from zkCli. Does anyone have some idea about this?Leader1:2010-10-30 07:34:08,546 [QuorumPeer:/0.0.0.0:5001] INFO QuorumPeer:620 - LOOKING2010-10-30 07:34:08,547 [QuorumPeer:/0.0.0.0:5001] INFO FastLeaderElection:649 - New election. My id = 4, Proposed zxid = 02010-10-30 07:34:08,550 [QuorumPeer:/0.0.0.0:5001] INFO FastLeaderElection:689 - Notification: 3, 0, 1, 4, LOOKING, LOOKING, 32010-10-30 07:34:08,551 [QuorumPeer:/0.0.0.0:5001] INFO FastLeaderElection:689 - Notification: 4, 0, 1, 4, LOOKING, LOOKING, 42010-10-30 07:34:08,552 [QuorumPeer:/0.0.0.0:5001] INFO FastLeaderElection:689 - Notification: 2, 0, 1, 4, LOOKING, LOOKING, 22010-10-30 07:34:08,553 [QuorumPeer:/0.0.0.0:5001] INFO FastLeaderElection:689 - Notification: 3, 0, 1, 4, LOOKING, LOOKING, 22010-10-30 07:34:08,553 [QuorumPeer:/0.0.0.0:5001] INFO FastLeaderElection:689 - Notification: 4, 0, 1, 4, LOOKING, LOOKING, 32010-10-30 07:34:08,554 [QuorumPeer:/0.0.0.0:5001] INFO FastLeaderElection:689 - Notification: 4, 0, 1, 4, LOOKING, LOOKING, 22010-10-30 07:34:08,805 [QuorumPeer:/0.0.0.0:5001] INFO QuorumPeer:654 - LEADING... kill it, restart it ...2010-10-30 08:01:29,868 [main] INFO QuorumPeerConfig:90 - Reading configuration from: /var/ zoo.cfg2010-10-30 08:01:29,876 [main] INFO QuorumPeerConfig:287 - Defaulting to majority quorums...2010-10-30 08:01:30,101 [QuorumPeer:/0.0.0.0:5001] INFO QuorumPeer:620 - LOOKING2010-10-30 08:01:30,120 [QuorumPeer:/0.0.0.0:5001] INFO QuorumPeer:654 - LEADING (chosen as leader again)Leader2:2010-10-30 07:34:08,531 [QuorumPeer:/0.0.0.0:5001] INFO QuorumPeer:620 - LOOKING2010-10-30 07:34:08,550 [QuorumPeer:/0.0.0.0:5001] INFO QuorumPeer:642 - FOLLOWING2010-10-30 07:58:58,064 [QuorumPeer:/0.0.0.0:5001] INFO QuorumPeer:620 - LOOKING2010-10-30 07:58:58,389 [QuorumPeer:/0.0.0.0:5001] INFO QuorumPeer:654 - LEADING (becomes the new leader)Thanks,Ruifang flaviojunqueiraresearch scientistf...@yahoo-inc.comdirect +34 93-183-8828avinguda diagonal 177, 8th floor, barcelona, 08018, esphone (408) 349 3300fax (408) 349 3301