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Date: Thu, 10 Aug 2017 23:50:00 +0000 (UTC)
From: "Michael Han (JIRA)" <jira@apache.org>
To: dev@zookeeper.apache.org
Message-ID: <JIRA.13092638.1501891132000.5619.1502409000183@Atlassian.JIRA>
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Subject: [jira] [Commented] (ZOOKEEPER-2867) an expired ZK session can be
 re-established
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archived-at: Thu, 10 Aug 2017 23:50:05 -0000


    [ https://issues.apache.org/jira/browse/ZOOKEEPER-2867?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16122553#comment-16122553 ] 

Michael Han commented on ZOOKEEPER-2867:
----------------------------------------

bq. If the pinging stops, ZK server should expire that session after the session timeout, right?

Correct. If the client dies ZK server should expire the session, eventually. 

bq. Did the session 0x25cd1e82c110001 ever get closed?

Based on what's discussed so far, I don't think this session is closed, because:
* There is no evidence that closing session proposal was committed.
* The ephemeral nodes associated with the session were not deleted. That is why later attempts to recreate same node get error {{-110}}, which means nodes already exist: {{DEBUG	org.apache.zookeeper.server.DataTree	Adjusting parent cversion for Txn: 1 path:/cp15/brokers/ids/0 err: -110}}.


> 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}


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