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Jun Rao edited comment on ZOOKEEPER-2867 at 8/7/17 11:50 PM: ------------------------------------------------------------- [~hanm], thanks for the reply. I am attaching the log of 2 of the 3 ZK servers around that time. During that window, there was some potential network issue that may prevent ZK servers from talking to each other. The network issue seems to be gone after 22:05:20, when the ZK cluster stabilized again. Assuming that session 25cd1e82c110001 didn't really get expired at that point, I got a followup question. A month later, the whole ZK cluster was done and was restarted. On restarting, I saw the following logging in ZK server about deleting an ephemeral in that session. {code:java} August 2nd 2017, 23:41:55.076 DEBUG org.apache.zookeeper.server.DataTree Deleting ephemeral node /cp15/brokers/ids/0 for session 0x25cd1e82c110001 {code} I assume that's because ZK server thinks that session is expired? However, in ZK server's commit log, I didn't find any entry about closing that session. Is that normal? Thanks, was (Author: junrao): [~hanm], thanks for the reply. I am attaching the log of 2 of the 3 ZK servers around that time. During that window, there was some potential network issue that may prevent ZK servers from talking to each other. The network issue seems to be gone after 22:05:20, when the ZK cluster stabilized again. Assuming that session 25cd1e82c110001 didn't really get expired at that point, I got a followup question. A month later, the whole ZK cluster was done and was restarted. On restarting, I saw the following logging in ZK server about deleting an ephemeral in that session. August 2nd 2017, 23:41:55.076 DEBUG org.apache.zookeeper.server.DataTree Deleting ephemeral node /cp15/brokers/ids/0 for session 0x25cd1e82c110001 I assume that's because ZK server thinks that session is expired? However, in ZK server's commit log, I didn't find any entry about closing that session. Is that normal? Thanks, > an expired ZK session can be re-established > ------------------------------------------- > > Key: ZOOKEEPER-2867 > URL: https://issues.apache.org/jira/browse/ZOOKEEPER-2867 > Project: ZooKeeper > Issue Type: Bug > Affects Versions: 3.4.10 > Reporter: Jun Rao > Attachments: zk.0.formatted, zk.1.formatted > > > 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. > {code:java} > 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 > {code} > From ZK client's log, it was able to renew the expired session on 22:05:20. > {code:java} > 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 > {code} -- This message was sent by Atlassian JIRA (v6.4.14#64029)