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https://issues.apache.org/jira/browse/FLINK-10052?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16882859#comment-16882859
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lamber-ken commented on FLINK-10052:
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Hi, all, I'm glad to fix this issue, when more and more jobs are deployed in
cluster, the impact will be very large. My thoughts are as follows :
1. If we upgrade curator dependency to 3.x or 4.x, because they just compatible
with ZooKeeper 3.5.x, so it needs user upgrade zookeeper cluster version too.
It is not very good to do that.
2. So, I think may by it's better to rewrite +LeaderLatch#handleStateChange+ at
flink-shaded-curator module.
> Tolerate temporarily suspended ZooKeeper connections
> ----------------------------------------------------
>
> Key: FLINK-10052
> URL: https://issues.apache.org/jira/browse/FLINK-10052
> Project: Flink
> Issue Type: Improvement
> Components: Runtime / Coordination
> Affects Versions: 1.4.2, 1.5.2, 1.6.0
> Reporter: Till Rohrmann
> Assignee: Dominik Wosiński
> Priority: Major
>
> This issue results from FLINK-10011 which uncovered a problem with Flink's HA
> recovery and proposed the following solution to harden Flink:
> The {{ZooKeeperLeaderElectionService}} uses the {{LeaderLatch}} Curator
> recipe for leader election. The leader latch revokes leadership in case of a
> suspended ZooKeeper connection. This can be premature in case that the system
> can reconnect to ZooKeeper before its session expires. The effect of the lost
> leadership is that all jobs will be canceled and directly restarted after
> regaining the leadership.
> Instead of directly revoking the leadership upon a SUSPENDED ZooKeeper
> connection, it would be better to wait until the ZooKeeper connection is
> LOST. That way we would allow the system to reconnect and not lose the
> leadership. This could be achievable by using Curator's {{LeaderSelector}}
> instead of the {{LeaderLatch}}.
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