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https://issues.apache.org/jira/browse/KAFKA-1305?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14361666#comment-14361666
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Jiangjie Qin commented on KAFKA-1305:
-------------------------------------
I see. The risk of this approach is that controller or broker could potentially
be in a inconsistent state. Because it is not necessarily the case that timeout
occurs on broker shutdown. In that case, some controller to broker messages are
sent while some might not.
I think the key problem of current approach is that we mix the data plain and
control plain, i.e. the controller message and user data are handled by same
request handlers on Kafka server. So controller messages usually sitting in the
queue behind many user requests. That could cause the handling of controller
messages to delay for almost arbitrary time (the more leader a broker has, the
worse the situation will be). The right solution is probably having a separate
thread handling controller message or prioritize controller message handling.
Giving priority to controller message probably has less change because we just
need to insert the controller message to the head of the queue instead of the
tail.
> Controller can hang on controlled shutdown with auto leader balance enabled
> ---------------------------------------------------------------------------
>
> Key: KAFKA-1305
> URL: https://issues.apache.org/jira/browse/KAFKA-1305
> Project: Kafka
> Issue Type: Bug
> Reporter: Joel Koshy
> Assignee: Sriharsha Chintalapani
> Priority: Blocker
> Fix For: 0.8.2.0, 0.9.0
>
> Attachments: KAFKA-1305.patch, KAFKA-1305.patch,
> KAFKA-1305_2014-10-13_07:30:45.patch
>
>
> This is relatively easy to reproduce especially when doing a rolling bounce.
> What happened here is as follows:
> 1. The previous controller was bounced and broker 265 became the new
> controller.
> 2. I went on to do a controlled shutdown of broker 265 (the new controller).
> 3. In the mean time the automatically scheduled preferred replica leader
> election process started doing its thing and starts sending
> LeaderAndIsrRequests/UpdateMetadataRequests to itself (and other brokers).
> (t@113 below).
> 4. While that's happening, the controlled shutdown process on 265 succeeds
> and proceeds to deregister itself from ZooKeeper and shuts down the socket
> server.
> 5. (ReplicaStateMachine actually removes deregistered brokers from the
> controller channel manager's list of brokers to send requests to. However,
> that removal cannot take place (t@18 below) because preferred replica leader
> election task owns the controller lock.)
> 6. So the request thread to broker 265 gets into infinite retries.
> 7. The entire broker shutdown process is blocked on controller shutdown for
> the same reason (it needs to acquire the controller lock).
> Relevant portions from the thread-dump:
> "Controller-265-to-broker-265-send-thread" - Thread t@113
> java.lang.Thread.State: TIMED_WAITING
> at java.lang.Thread.sleep(Native Method)
> at
> kafka.controller.RequestSendThread$$anonfun$liftedTree1$1$1.apply$mcV$sp(ControllerChannelManager.scala:143)
> at kafka.utils.Utils$.swallow(Utils.scala:167)
> at kafka.utils.Logging$class.swallowWarn(Logging.scala:92)
> at kafka.utils.Utils$.swallowWarn(Utils.scala:46)
> at kafka.utils.Logging$class.swallow(Logging.scala:94)
> at kafka.utils.Utils$.swallow(Utils.scala:46)
> at
> kafka.controller.RequestSendThread.liftedTree1$1(ControllerChannelManager.scala:143)
> at
> kafka.controller.RequestSendThread.doWork(ControllerChannelManager.scala:131)
> - locked java.lang.Object@6dbf14a7
> at kafka.utils.ShutdownableThread.run(ShutdownableThread.scala:51)
> Locked ownable synchronizers:
> - None
> ...
> "Thread-4" - Thread t@17
> java.lang.Thread.State: WAITING on
> java.util.concurrent.locks.ReentrantLock$NonfairSync@4836840 owned by:
> kafka-scheduler-0
> at sun.misc.Unsafe.park(Native Method)
> at java.util.concurrent.locks.LockSupport.park(LockSupport.java:156)
> at
> java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:811)
> at
> java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireQueued(AbstractQueuedSynchronizer.java:842)
> at
> java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(AbstractQueuedSynchronizer.java:1178)
> at
> java.util.concurrent.locks.ReentrantLock$NonfairSync.lock(ReentrantLock.java:186)
> at java.util.concurrent.locks.ReentrantLock.lock(ReentrantLock.java:262)
> at kafka.utils.Utils$.inLock(Utils.scala:536)
> at kafka.controller.KafkaController.shutdown(KafkaController.scala:642)
> at
> kafka.server.KafkaServer$$anonfun$shutdown$9.apply$mcV$sp(KafkaServer.scala:242)
> at kafka.utils.Utils$.swallow(Utils.scala:167)
> at kafka.utils.Logging$class.swallowWarn(Logging.scala:92)
> at kafka.utils.Utils$.swallowWarn(Utils.scala:46)
> at kafka.utils.Logging$class.swallow(Logging.scala:94)
> at kafka.utils.Utils$.swallow(Utils.scala:46)
> at kafka.server.KafkaServer.shutdown(KafkaServer.scala:242)
> at
> kafka.server.KafkaServerStartable.shutdown(KafkaServerStartable.scala:46)
> at kafka.Kafka$$anon$1.run(Kafka.scala:42)
> ...
> "kafka-scheduler-0" - Thread t@117
> java.lang.Thread.State: WAITING on
> java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject@1dc407fc
> at sun.misc.Unsafe.park(Native Method)
> at java.util.concurrent.locks.LockSupport.park(LockSupport.java:156)
> at
> java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:1987)
> at
> java.util.concurrent.LinkedBlockingQueue.put(LinkedBlockingQueue.java:306)
> at
> kafka.controller.ControllerChannelManager.sendRequest(ControllerChannelManager.scala:57)
> - locked java.lang.Object@578b748f
> at
> kafka.controller.KafkaController.sendRequest(KafkaController.scala:657)
> at
> kafka.controller.ControllerBrokerRequestBatch$$anonfun$sendRequestsToBrokers$2.apply(ControllerChannelManager.scala:290)
> at
> kafka.controller.ControllerBrokerRequestBatch$$anonfun$sendRequestsToBrokers$2.apply(ControllerChannelManager.scala:282)
> at
> scala.collection.mutable.HashMap$$anonfun$foreach$1.apply(HashMap.scala:80)
> at
> scala.collection.mutable.HashMap$$anonfun$foreach$1.apply(HashMap.scala:80)
> at scala.collection.Iterator$class.foreach(Iterator.scala:631)
> at
> scala.collection.mutable.HashTable$$anon$1.foreach(HashTable.scala:161)
> at
> scala.collection.mutable.HashTable$class.foreachEntry(HashTable.scala:194)
> at scala.collection.mutable.HashMap.foreachEntry(HashMap.scala:39)
> at scala.collection.mutable.HashMap.foreach(HashMap.scala:80)
> at
> kafka.controller.ControllerBrokerRequestBatch.sendRequestsToBrokers(ControllerChannelManager.scala:282)
> at
> kafka.controller.PartitionStateMachine.handleStateChanges(PartitionStateMachine.scala:126)
> at
> kafka.controller.KafkaController.onPreferredReplicaElection(KafkaController.scala:612)
> at
> kafka.controller.KafkaController$$anonfun$kafka$controller$KafkaController$$checkAndTriggerPartitionRebalance$4$$anonfun$apply$17$$anonfun$apply$5.apply$mcV$sp(KafkaController.scala:1119)
> at
> kafka.controller.KafkaController$$anonfun$kafka$controller$KafkaController$$checkAndTriggerPartitionRebalance$4$$anonfun$apply$17$$anonfun$apply$5.apply(KafkaController.scala:1114)
> at
> kafka.controller.KafkaController$$anonfun$kafka$controller$KafkaController$$checkAndTriggerPartitionRebalance$4$$anonfun$apply$17$$anonfun$apply$5.apply(KafkaController.scala:1114)
> at kafka.utils.Utils$.inLock(Utils.scala:538)
> at
> kafka.controller.KafkaController$$anonfun$kafka$controller$KafkaController$$checkAndTriggerPartitionRebalance$4$$anonfun$apply$17.apply(KafkaController.scala:1111)
> at
> kafka.controller.KafkaController$$anonfun$kafka$controller$KafkaController$$checkAndTriggerPartitionRebalance$4$$anonfun$apply$17.apply(KafkaController.scala:1109)
> at
> scala.collection.mutable.HashMap$$anonfun$foreach$1.apply(HashMap.scala:80)
> at
> scala.collection.mutable.HashMap$$anonfun$foreach$1.apply(HashMap.scala:80)
> at scala.collection.Iterator$class.foreach(Iterator.scala:631)
> at
> scala.collection.mutable.HashTable$$anon$1.foreach(HashTable.scala:161)
> at
> scala.collection.mutable.HashTable$class.foreachEntry(HashTable.scala:194)
> at scala.collection.mutable.HashMap.foreachEntry(HashMap.scala:39)
> at scala.collection.mutable.HashMap.foreach(HashMap.scala:80)
> at
> kafka.controller.KafkaController$$anonfun$kafka$controller$KafkaController$$checkAndTriggerPartitionRebalance$4.apply(KafkaController.scala:1109)
> at
> kafka.controller.KafkaController$$anonfun$kafka$controller$KafkaController$$checkAndTriggerPartitionRebalance$4.apply(KafkaController.scala:1088)
> at
> scala.collection.immutable.HashMap$HashMap1.foreach(HashMap.scala:125)
> at
> scala.collection.immutable.HashMap$HashTrieMap.foreach(HashMap.scala:344)
> at
> kafka.controller.KafkaController.kafka$controller$KafkaController$$checkAndTriggerPartitionRebalance(KafkaController.scala:1088)
> at
> kafka.controller.KafkaController$$anonfun$onControllerFailover$1.apply$mcV$sp(KafkaController.scala:323)
> at kafka.utils.KafkaScheduler$$anon$1.run(KafkaScheduler.scala:100)
> at
> java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
> at
> java.util.concurrent.FutureTask$Sync.innerRunAndReset(FutureTask.java:317)
> at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:150)
> at
> java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$101(ScheduledThreadPoolExecutor.java:98)
> at
> java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.runPeriodic(ScheduledThreadPoolExecutor.java:180)
> at
> java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:204)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
> at java.lang.Thread.run(Thread.java:662)
> Locked ownable synchronizers:
> - locked java.util.concurrent.locks.ReentrantLock$NonfairSync@4836840
> - locked java.util.concurrent.locks.ReentrantLock$NonfairSync@4918530
> ...
> "ZkClient-EventThread-18-/kafka-shadow" - Thread t@18
> java.lang.Thread.State: WAITING on
> java.util.concurrent.locks.ReentrantLock$NonfairSync@4836840 owned by:
> kafka-scheduler-0
> at sun.misc.Unsafe.park(Native Method)
> at java.util.concurrent.locks.LockSupport.park(LockSupport.java:156)
> at
> java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:811)
> at
> java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireQueued(AbstractQueuedSynchronizer.java:842)
> at
> java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(AbstractQueuedSynchronizer.java:1178)
> at
> java.util.concurrent.locks.ReentrantLock$NonfairSync.lock(ReentrantLock.java:186)
> at java.util.concurrent.locks.ReentrantLock.lock(ReentrantLock.java:262)
> at kafka.utils.Utils$.inLock(Utils.scala:536)
> at
> kafka.controller.ReplicaStateMachine$BrokerChangeListener.handleChildChange(ReplicaStateMachine.scala:328)
> at org.I0Itec.zkclient.ZkClient$7.run(ZkClient.java:568)
> at org.I0Itec.zkclient.ZkEventThread.run(ZkEventThread.java:71)
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