[jira] [Updated] (KAFKA-589) Clean shutdown after startup connection failure

["Ewen Cheslack-Postava (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/KAFKA-589?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Ewen Cheslack-Postava updated KAFKA-589:
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    Status: Patch Available  (was: Open)

This patch makes KafkaServer clean up after itself, but still rethrow any caught exceptions. This keeps the existing interface the same, should still work if the caller does cleanup themselves by catching exceptions and calling shutdown, but also cleans up if they don't so the leftover thread won't cause a hang. Also adds a test of this behavior.

> 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: 0.8.0, 0.7.2
>            Reporter: Jason Rosenberg
>            Assignee: Swapnil Ghike
>            Priority: Minor
>              Labels: bugs, newbie
>
> 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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