[jira] Commented: (ZOOKEEPER-131) Old leader election can elect a dead leader over and over again
[ https://issues.apache.org/jira/browse/ZOOKEEPER-131?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12632933#action_12632933 ] Hudson commented on ZOOKEEPER-131: -- Integrated in ZooKeeper-trunk #89 (See [http://hudson.zones.apache.org/hudson/job/ZooKeeper-trunk/89/]) > Old leader election can elect a dead leader over and over again > --- > > Key: ZOOKEEPER-131 > URL: https://issues.apache.org/jira/browse/ZOOKEEPER-131 > Project: Zookeeper > Issue Type: Bug > Components: leaderElection >Reporter: Benjamin Reed >Assignee: Benjamin Reed > Fix For: 3.0.0 > > Attachments: ZOOKEEPER-131.patch, ZOOKEEPER-131.patch, > ZOOKEEPER-131.patch > > > I think there is a race condition that is probably easy to get into with the > old leader election and a large number of servers: > 1) Leader dies > 2) Followers start looking for a new leader before all Followers have > abandoned the Leader > 3) The Followers looking for a new leader see votes of Followers still > following the (now dead) Leader and start voting for the dead Leader > 4) The dead Leader gets reelected. > For the old leader election a server should not vote for another server that > is not nominating himself. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-131) Old leader election can elect a dead leader over and over again
[ https://issues.apache.org/jira/browse/ZOOKEEPER-131?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12632120#action_12632120 ] Austin Shoemaker commented on ZOOKEEPER-131: This patch appears to solve the problem for algorithm 0- our unit test completed successfully 16 times. > Old leader election can elect a dead leader over and over again > --- > > Key: ZOOKEEPER-131 > URL: https://issues.apache.org/jira/browse/ZOOKEEPER-131 > Project: Zookeeper > Issue Type: Bug > Components: leaderElection >Reporter: Benjamin Reed >Assignee: Benjamin Reed > Attachments: ZOOKEEPER-131.patch > > > I think there is a race condition that is probably easy to get into with the > old leader election and a large number of servers: > 1) Leader dies > 2) Followers start looking for a new leader before all Followers have > abandoned the Leader > 3) The Followers looking for a new leader see votes of Followers still > following the (now dead) Leader and start voting for the dead Leader > 4) The dead Leader gets reelected. > For the old leader election a server should not vote for another server that > is not nominating himself. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (ZOOKEEPER-131) Old leader election can elect a dead leader over and over again
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https://issues.apache.org/jira/browse/ZOOKEEPER-131?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12632016#action_12632016
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Flavio Paiva Junqueira commented on ZOOKEEPER-131:
--
+1 for the patch. The only suggestion I have is to replace e.printStackTrace()
statements with LOG("msg", e) statements. I received this comment on another
patch, so I'm just passing the message along. :-)
> Old leader election can elect a dead leader over and over again
> ---
>
> Key: ZOOKEEPER-131
> URL: https://issues.apache.org/jira/browse/ZOOKEEPER-131
> Project: Zookeeper
> Issue Type: Bug
> Components: leaderElection
>Reporter: Benjamin Reed
>Assignee: Benjamin Reed
> Attachments: ZOOKEEPER-131.patch
>
>
> I think there is a race condition that is probably easy to get into with the
> old leader election and a large number of servers:
> 1) Leader dies
> 2) Followers start looking for a new leader before all Followers have
> abandoned the Leader
> 3) The Followers looking for a new leader see votes of Followers still
> following the (now dead) Leader and start voting for the dead Leader
> 4) The dead Leader gets reelected.
> For the old leader election a server should not vote for another server that
> is not nominating himself.
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