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https://issues.apache.org/jira/browse/ZOOKEEPER-2867?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16134630#comment-16134630
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Michael Han commented on ZOOKEEPER-2867:
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bq. the old ZK session for broker 0 (25cd1e82c110001) should be expired after
the ZK servers were restarted (but it didn't seem to happen).
The expected behavior in this case is actually opposite: when ZK servers
restarts, as long as clients, including broker 0 can reconnect to ZK within the
configured time limits, the session will be renewed. This is because when ZK
server restarts (or when it loses quorum during LE), the clock used for session
timeout stops ticking until a new quorum is formed. In this case the ZK servers
were down (23:16) before broker 0 is down (23:17) so it's totally possible for
broker 0 to renew the session.
bq. In ZK server 1's commit log, I saw the following, which indicates that
session 25cd1e82c110001 was closed.
Could you please point to me the file name of the attached log that appertains
to this? I don't find the file (the latest attached log file has dates as 8/02
instead of 6/27).
> 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.0.08-02, zk.0.08-02, zk.0.formatted, zk.1.08-02,
> zk.1.08-02, zk.1.formatted, zk.2.08-02, zk.2.08-02
>
>
> 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}
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