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https://issues.apache.org/jira/browse/KAFKA-589?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14148726#comment-14148726
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Neha Narkhede commented on KAFKA-589:
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Thanks for fixing a longstanding bug! +1 on the patch.
> Clean shutdown after startup connection failure
> -----------------------------------------------
>
> Key: KAFKA-589
> URL: https://issues.apache.org/jira/browse/KAFKA-589
> Project: Kafka
> Issue Type: Bug
> Components: core
> Affects Versions: 0.7.2, 0.8.0
> Reporter: Jason Rosenberg
> Assignee: Swapnil Ghike
> Priority: Minor
> Labels: bugs, newbie
> Attachments: KAFKA-589-v1.patch
>
>
> Hi,
> I'm embedding the kafka server (0.7.2) in an application container. I've
> noticed that if I try to start the server without zookeeper being available,
> by default it gets a zk connection timeout after 6 seconds, and then throws
> an Exception out of KafkaServer.startup()....E.g., I see this stack trace:
> Exception in thread "main" org.I0Itec.zkclient.exception.ZkTimeoutException:
> Unable to connect to zookeeper server within timeout: 6000
> at org.I0Itec.zkclient.ZkClient.connect(ZkClient.java:876)
> at org.I0Itec.zkclient.ZkClient.<init>(ZkClient.java:98)
> at org.I0Itec.zkclient.ZkClient.<init>(ZkClient.java:84)
> at kafka.server.KafkaZooKeeper.startup(KafkaZooKeeper.scala:44)
> at kafka.log.LogManager.<init>(LogManager.scala:93)
> at kafka.server.KafkaServer.startup(KafkaServer.scala:58)
> ....
> ....
> So that's ok, I can catch the exception, and then shut everything down
> gracefully, in this case. However, when I do this, it seems there is a
> daemon thread still around, which doesn't quit, and so the server never
> actually exits the jvm. Specifically, this thread seems to hang around:
> "kafka-logcleaner-0" prio=5 tid=7fd9b48b1000 nid=0x112c08000 waiting on
> condition [112c07000]
> java.lang.Thread.State: TIMED_WAITING (parking)
> at sun.misc.Unsafe.park(Native Method)
> - parking to wait for <7f40d4be8> (a
> java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
> at
> java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:196)
> at
> java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2025)
> at java.util.concurrent.DelayQueue.take(DelayQueue.java:164)
> at
> java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:609)
> at
> java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:602)
> at
> java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:947)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:907)
> at java.lang.Thread.run(Thread.java:680)
> Looking at the code in kafka.log.LogManager(), it does seem like it starts up
> the scheduler to clean logs, before then trying to connect to zk (and in this
> case fail):
> /* Schedule the cleanup task to delete old logs */
> if(scheduler != null) {
> info("starting log cleaner every " + logCleanupIntervalMs + " ms")
> scheduler.scheduleWithRate(cleanupLogs, 60 * 1000, logCleanupIntervalMs)
> }
> So this scheduler does not appear to be stopped if startup fails. However,
> if I catch the above RuntimeException, and then call KafkaServer.shutdown(),
> then it will stop the scheduler, and all is good.
> However, it seems odd that if I get an exception when calling
> KafkaServer.startup(), that I should still have to do a
> KafkaServer.shutdown(). Rather, wouldn't it be better to have it internally
> cleanup after itself if startup() gets an exception? I'm not sure I can
> reliably call shutdown() after a failed startup()....
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