[jira] [Created] (KAFKA-5242) state task directory locked forever

["Lukas Gemela (JIRA)" <ji...@apache.org>]

Lukas Gemela created KAFKA-5242:
-----------------------------------

             Summary: state task directory locked forever
                 Key: KAFKA-5242
                 URL: https://issues.apache.org/jira/browse/KAFKA-5242
             Project: Kafka
          Issue Type: Bug
          Components: streams
    Affects Versions: 0.10.2.0
            Reporter: Lukas Gemela
         Attachments: clio_170511.log

From time to time, during relabance we are getting a lot of exceptions saying 

{code}
org.apache.kafka.streams.errors.LockException: task [0_0] Failed to lock the state directory: /app/db/clio/0_0
	at org.apache.kafka.streams.processor.internals.ProcessorStateManager.<init>(ProcessorStateManager.java:102) ~[kafka-streams-0.10.2.0.jar!/:?]
	at org.apache.kafka.streams.processor.internals.AbstractTask.<init>(AbstractTask.java:73) ~[kafka-streams-0.10.2.0.jar!/:?]
	at org.apache.kafka.streams.processor.internals.StreamTask.<init>(StreamTask.java:108) ~[kafka-streams-0.10.2.0.jar!/:?]
	at org.apache.kafka.streams.processor.internals.StreamThread.createStreamTask(StreamThread.java:834) ~[kafka-streams-0.10.2.0.jar!/:?]
	at org.apache.kafka.streams.processor.internals.StreamThread$TaskCreator.createTask(StreamThread.java:1207) ~[kafka-streams-0.10.2.0.jar!/:?]
	at org.apache.kafka.streams.processor.internals.StreamThread$AbstractTaskCreator.retryWithBackoff(StreamThread.java:1180) [kafka-streams-0.10.2.0.jar!/:?]
	at org.apache.kafka.streams.processor.internals.StreamThread.addStreamTasks(StreamThread.java:937) [kafka-streams-0.10.2.0.jar!/:?]
	at org.apache.kafka.streams.processor.internals.StreamThread.access$500(StreamThread.java:69) [kafka-streams-0.10.2.0.jar!/:?]
	at org.apache.kafka.streams.processor.internals.StreamThread$1.onPartitionsAssigned(StreamThread.java:236) [kafka-streams-0.10.2.0.jar!/:?]
	at org.apache.kafka.clients.consumer.internals.ConsumerCoordinator.onJoinComplete(ConsumerCoordinator.java:255) [kafka-clients-0.10.2.0.jar!/:?]
	at org.apache.kafka.clients.consumer.internals.AbstractCoordinator.joinGroupIfNeeded(AbstractCoordinator.java:339) [kafka-clients-0.10.2.0.jar!/:?]
	at org.apache.kafka.clients.consumer.internals.AbstractCoordinator.ensureActiveGroup(AbstractCoordinator.java:303) [kafka-clients-0.10.2.0.jar!/:?]
	at org.apache.kafka.clients.consumer.internals.ConsumerCoordinator.poll(ConsumerCoordinator.java:286) [kafka-clients-0.10.2.0.jar!/:?]
	at org.apache.kafka.clients.consumer.KafkaConsumer.pollOnce(KafkaConsumer.java:1030) [kafka-clients-0.10.2.0.jar!/:?]
	at org.apache.kafka.clients.consumer.KafkaConsumer.poll(KafkaConsumer.java:995) [kafka-clients-0.10.2.0.jar!/:?]
	at org.apache.kafka.streams.processor.internals.StreamThread.runLoop(StreamThread.java:582) [kafka-streams-0.10.2.0.jar!/:?]
	at org.apache.kafka.streams.processor.internals.StreamThread.run(StreamThread.java:368) [kafka-streams-0.10.2.0.jar!/:?]
{code}

(see attached logfile)

By looking at the code looks like the some old tasks are never being closed and the lock is never released.

Also, the backoff strategy in StreamThread$AbstractTaskCreator.retryWithBackoff can run endlessly - after 20 iterations it takes 6hours until the next attempt to start a task. 
I've noticed latest code contains check for rebalanceTimeoutMs, but that still does not solve the problem especially in case MAX_POLL_INTERVAL_MS_CONFIG is set to Integer.MAX_INT. 

I would personally make that backoffstrategy a bit more configurable with a number of retries that if it exceed a configured value it propagates the exception as any other exception to custom client exception handler.
(I can provide a patch)



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