Hi team, This exception occurs regularly on our brokers. When it occurs, a broker will lose its leader role but still in ISR. And running preferred-leader-election script may rebalance the leadership but in some cases it does not help.
[2013-11-14 08:04:40,001] INFO Processed session termination for sessionid: 0x34250e8160b0360 (org.apache.zookee per.server.PrepRequestProcessor) [2013-11-14 08:04:40,001] INFO Processed session termination for sessionid: 0x24250e816b00341 (org.apache.zookee per.server.PrepRequestProcessor) [2013-11-14 08:04:41,909] ERROR Unexpected exception causing shutdown while sock still open (org.apache.zookeepe r.server.quorum.LearnerHandler) java.io.EOFException at java.io.DataInputStream.readInt(DataInputStream.java:392) at org.apache.jute.BinaryInputArchive.readInt(BinaryInputArchive.java:63) at org.apache.zookeeper.server.quorum.QuorumPacket.deserialize(QuorumPacket.java:84) at org.apache.jute.BinaryInputArchive.readRecord(BinaryInputArchive.java:108) at org.apache.zookeeper.server.quorum.LearnerHandler.run(LearnerHandler.java:413) [2013-11-14 08:04:41,917] WARN ******* GOODBYE /xxx.xxx.xx.xx:59352 ******** (org.apache.zookeeper.server.quorum.LearnerHandler) [2013-11-14 08:04:41,926] INFO Got user-level KeeperException when processing sessionid:0x24250e816b00348 type:setData cxid:0x7e4 zxid:0xfffffffffffffffe txntype:unknown reqpath:/consumers/myusergroup/offsets/mytopic/1 Error Path:null Error:KeeperErrorCode = Session expired (org.apache.zookeeper.server.PrepRequestProcessor) [2013-11-14 08:04:42,000] INFO Expiring session 0x24242764c0b0000, timeout of 10000ms exceeded (org.apache.zookeeper.server.ZooKeeperServer) [2013-11-14 08:04:42,001] INFO Processed session termination for sessionid: 0x24242764c0b0000 (org.apache.zookeeper.server.PrepRequestProcessor) [2013-11-14 08:04:42,002] INFO Closed socket connection for client /xxx.xxx.xx.xx:41654 which had sessionid 0x24242764c0b0000 (org.apache.zookeeper.server.NIOServerCnxn) [2013-11-14 08:04:42,064] INFO Got user-level KeeperException when processing sessionid:0x14250e816040000 type:create cxid:0x11 zxid:0xfffffffffffffffe txntype:unknown reqpath:n/a Error Path:/controller Error:KeeperErrorCode = NodeExists for /controller (org.apache.zookeeper.server.PrepRequestProcessor) [2013-11-14 08:04:42,065] INFO conflict in /controller data: 3 stored data: 2 (kafka.utils.ZkUtils$) [2013-11-14 08:04:42,067] INFO New leader is 2 (kafka.server.ZookeeperLeaderElector$LeaderChangeListener) Regards, Libo