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https://issues.apache.org/jira/browse/KAFKA-8185?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Dhruvil Shah resolved KAFKA-8185.
---------------------------------
Resolution: Not A Problem
This is not a typically expected scenario and would only happen when the topic
znode is deleted directly from ZK.
> Controller becomes stale and not able to failover the leadership for the
> partitions
> -----------------------------------------------------------------------------------
>
> Key: KAFKA-8185
> URL: https://issues.apache.org/jira/browse/KAFKA-8185
> Project: Kafka
> Issue Type: Bug
> Components: controller
> Affects Versions: 1.1.1
> Reporter: Kang H Lee
> Priority: Critical
> Attachments: broker12.zip, broker9.zip, zookeeper.zip
>
>
> Description:
> After broker 9 went offline, all partitions led by it went offline. The
> controller attempted to move leadership but ran into an exception while doing
> so:
> {code:java}
> // [2019-03-26 01:23:34,114] ERROR [PartitionStateMachine controllerId=12]
> Error while moving some partitions to OnlinePartition state
> (kafka.controller.PartitionStateMachine)
> java.util.NoSuchElementException: key not found: me-test-1
> at scala.collection.MapLike$class.default(MapLike.scala:228)
> at scala.collection.AbstractMap.default(Map.scala:59)
> at scala.collection.mutable.HashMap.apply(HashMap.scala:65)
> at
> kafka.controller.PartitionStateMachine$$anonfun$14.apply(PartitionStateMachine.scala:202)
> at
> kafka.controller.PartitionStateMachine$$anonfun$14.apply(PartitionStateMachine.scala:202)
> at
> scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:234)
> at
> scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:234)
> at
> scala.collection.mutable.ResizableArray$class.foreach(ResizableArray.scala:59)
> at scala.collection.mutable.ArrayBuffer.foreach(ArrayBuffer.scala:48)
> at scala.collection.TraversableLike$class.map(TraversableLike.scala:234)
> at scala.collection.AbstractTraversable.map(Traversable.scala:104)
> at
> kafka.controller.PartitionStateMachine.initializeLeaderAndIsrForPartitions(PartitionStateMachine.scala:202)
> at
> kafka.controller.PartitionStateMachine.doHandleStateChanges(PartitionStateMachine.scala:167)
> at
> kafka.controller.PartitionStateMachine.handleStateChanges(PartitionStateMachine.scala:116)
> at
> kafka.controller.PartitionStateMachine.triggerOnlinePartitionStateChange(PartitionStateMachine.scala:106)
> at
> kafka.controller.KafkaController.kafka$controller$KafkaController$$onReplicasBecomeOffline(KafkaController.scala:437)
> at
> kafka.controller.KafkaController.kafka$controller$KafkaController$$onBrokerFailure(KafkaController.scala:405)
> at
> kafka.controller.KafkaController$BrokerChange$.process(KafkaController.scala:1246)
> at
> kafka.controller.ControllerEventManager$ControllerEventThread$$anonfun$doWork$1.apply$mcV$sp(ControllerEventManager.scala:69)
> at
> kafka.controller.ControllerEventManager$ControllerEventThread$$anonfun$doWork$1.apply(ControllerEventManager.scala:69)
> at
> kafka.controller.ControllerEventManager$ControllerEventThread$$anonfun$doWork$1.apply(ControllerEventManager.scala:69)
> at kafka.metrics.KafkaTimer.time(KafkaTimer.scala:31)
> at
> kafka.controller.ControllerEventManager$ControllerEventThread.doWork(ControllerEventManager.scala:68)
> at kafka.utils.ShutdownableThread.run(ShutdownableThread.scala:82)
> {code}
> The controller was unable to move leadership of partitions led by broker 9 as
> a result. It's worth noting that the controller ran into the same exception
> when the broker came back up online. The controller thinks `me-test-1` is a
> new partition and when attempting to transition it to an online partition, it
> is unable to retrieve its replica assignment from
> ControllerContext#partitionReplicaAssignment. I need to look through the code
> to figure out if there's a race condition or situations where we remove the
> partition from ControllerContext#partitionReplicaAssignment but might still
> leave it in PartitionStateMachine#partitionState.
> They had to change the controller to recover from the offline status.
> Sequential event:
> * Broker 9 got restated in between : 2019-03-26 01:22:54,236 - 2019-03-26
> 01:27:30,967: This was unclean shutdown.
> * From 2019-03-26 01:27:30,967, broker 9 was rebuilding indexes. Broker 9
> wasn't able to process data at this moment.
> * At 2019-03-26 01:29:36,741, broker 9 was starting to load replica.
> * [2019-03-26 01:29:36,202] ERROR [KafkaApi-9] Number of alive brokers '0'
> does not meet the required replication factor '3' for the offsets topic
> (configured via 'offsets.topic.replication.factor'). This error can be
> ignored if the cluster is starting up and not all brokers are up yet.
> (kafka.server.KafkaApis)
> * At 2019-03-26 01:29:37,270, broker 9 started report offline partitions.
>
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