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https://issues.apache.org/jira/browse/FLINK-10052?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17330858#comment-17330858
]
Chen Qin commented on FLINK-10052:
----------------------------------
run load testing on pr, found following exception when job restarts.
{code:java}
2021-04-21 18:24:44,639 ERROR
org.apache.flink.runtime.taskexecutor.TaskExecutor - Fatal error
occurred in TaskExecutor akka.tcp://flink@xxx:33435/user/rpc/taskmanager_0.
org.apache.flink.util.FlinkException: Unhandled error in
ZooKeeperLeaderRetrievalService:Background operation retry gave up
at
org.apache.flink.runtime.leaderretrieval.ZooKeeperLeaderRetrievalService.unhandledError(ZooKeeperLeaderRetrievalService.java:208)
at
org.apache.flink.shaded.curator4.org.apache.curator.framework.imps.CuratorFrameworkImpl$6.apply(CuratorFrameworkImpl.java:713)
at
org.apache.flink.shaded.curator4.org.apache.curator.framework.imps.CuratorFrameworkImpl$6.apply(CuratorFrameworkImpl.java:709)
at
org.apache.flink.shaded.curator4.org.apache.curator.framework.listen.ListenerContainer$1.run(ListenerContainer.java:100)
at
org.apache.flink.shaded.curator4.org.apache.curator.shaded.com.google.common.util.concurrent.DirectExecutor.execute(DirectExecutor.java:30)
at
org.apache.flink.shaded.curator4.org.apache.curator.framework.listen.ListenerContainer.forEach(ListenerContainer.java:92)
at
org.apache.flink.shaded.curator4.org.apache.curator.framework.imps.CuratorFrameworkImpl.logError(CuratorFrameworkImpl.java:708)
at
org.apache.flink.shaded.curator4.org.apache.curator.framework.imps.CuratorFrameworkImpl.checkBackgroundRetry(CuratorFrameworkImpl.java:874)
at
org.apache.flink.shaded.curator4.org.apache.curator.framework.imps.CuratorFrameworkImpl.performBackgroundOperation(CuratorFrameworkImpl.java:990)
at
org.apache.flink.shaded.curator4.org.apache.curator.framework.imps.CuratorFrameworkImpl.backgroundOperationsLoop(CuratorFrameworkImpl.java:943)
at
org.apache.flink.shaded.curator4.org.apache.curator.framework.imps.CuratorFrameworkImpl.access$300(CuratorFrameworkImpl.java:66)
at
org.apache.flink.shaded.curator4.org.apache.curator.framework.imps.CuratorFrameworkImpl$4.call(CuratorFrameworkImpl.java:346)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at
java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180)
at
java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293)
at
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
Caused by:
org.apache.flink.shaded.zookeeper3.org.apache.zookeeper.KeeperException$ConnectionLossException:
KeeperErrorCode = ConnectionLoss
at
org.apache.flink.shaded.zookeeper3.org.apache.zookeeper.KeeperException.create(KeeperException.java:102)
at
org.apache.flink.shaded.curator4.org.apache.curator.framework.imps.CuratorFrameworkImpl.checkBackgroundRetry(CuratorFrameworkImpl.java:862)
... 10 more
{code}
> 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, 1.8.1
> Reporter: Till Rohrmann
> Assignee: Zili Chen
> Priority: Major
> Labels: pull-request-available, stale-assigned
> Fix For: 1.13.0
>
> Time Spent: 50m
> Remaining Estimate: 0h
>
> 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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