[ZOOKEEPER-2867] an expired ZK session can be re-established

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 3.4.10
• Assignee: Michael Han
• Reporter: Jun Rao
• Created: 04/Aug/17 23:58
• Updated: 07/Dec/23 17:57

Description

Not sure if this is a real bug, but I found an instance when a ZK client seems to be able to renew a session already expired by the ZK server.

From ZK server log, session 25cd1e82c110001 was expired at 22:04:39.

June 27th 2017, 22:04:39.000	INFO	org.apache.zookeeper.server.ZooKeeperServer	Expiring session 0x25cd1e82c110001, timeout of 12000ms exceeded
June 27th 2017, 22:04:39.001	DEBUG	org.apache.zookeeper.server.quorum.Leader	Proposing:: sessionid:0x25cd1e82c110001 type:closeSession cxid:0x0 zxid:0x200000fc4 txntype:-11 reqpath:n/a
June 27th 2017, 22:04:39.001	INFO	org.apache.zookeeper.server.PrepRequestProcessor	Processed session termination for sessionid: 0x25cd1e82c110001
June 27th 2017, 22:04:39.001	DEBUG	org.apache.zookeeper.server.quorum.CommitProcessor	Processing request:: sessionid:0x25cd1e82c110001 type:closeSession cxid:0x0 zxid:0x200000fc4 txntype:-11 reqpath:n/a
June 27th 2017, 22:05:20.324	INFO	org.apache.zookeeper.server.quorum.Learner	Revalidating client: 0x25cd1e82c110001
June 27th 2017, 22:05:20.324	INFO	org.apache.zookeeper.server.ZooKeeperServer	Client attempting to renew session 0x25cd1e82c110001 at /100.96.5.6:47618
June 27th 2017, 22:05:20.325	INFO	org.apache.zookeeper.server.ZooKeeperServer	Established session 0x25cd1e82c110001 with negotiated timeout 12000 for client /100.96.5.6:47618

From ZK client's log, it was able to renew the expired session on 22:05:20.

June 27th 2017, 22:05:18.590	INFO	org.apache.zookeeper.ClientCnxn	Client session timed out, have not heard from server in 4485ms for sessionid 0x25cd1e82c110001, closing socket connection and attempting reconnect	0
June 27th 2017, 22:05:18.590	WARN	org.apache.zookeeper.ClientCnxn	Client session timed out, have not heard from server in 4485ms for sessionid 0x25cd1e82c110001	0
June 27th 2017, 22:05:19.325	WARN	org.apache.zookeeper.ClientCnxn	SASL configuration failed: javax.security.auth.login.LoginException: No JAAS configuration section named 'Client' was found in specified JAAS configuration file: '/opt/confluent/etc/kafka/server_jaas.conf'. Will continue connection to Zookeeper server without SASL authentication, if Zookeeper server allows it.	0
June 27th 2017, 22:05:19.326	INFO	org.apache.zookeeper.ClientCnxn	Opening socket connection to server 100.65.188.168/100.65.188.168:2181	0
June 27th 2017, 22:05:20.324	INFO	org.apache.zookeeper.ClientCnxn	Socket connection established to 100.65.188.168/100.65.188.168:2181, initiating session	0
June 27th 2017, 22:05:20.327	INFO	org.apache.zookeeper.ClientCnxn	Session establishment complete on server 100.65.188.168/100.65.188.168:2181, sessionid = 0x25cd1e82c110001, negotiated timeout = 12000	0

Issue Links

• relates to: KAFKA-15844 Broker doesn't re-register after losing ZK session