Hi Jun, Thanks for responding...
I am using Kafka 2.9.2-0.8.1.1 I looked through the controller logs on a couple of nodes and did not find any exceptions or error. However in the state change log I see a bunch of the following exceptions - [2014-10-13 14:39:12,475] TRACE Controller 3 epoch 116 started leader election for partition [wordcount,1] (state.change.logger) [2014-10-13 14:39:12,479] ERROR Controller 3 epoch 116 initiated state change for partition [wordcount,1] from OfflinePartition to OnlinePartition failed (state.change.logger) kafka.common.NoReplicaOnlineException: No replica for partition [wordcount,1] is alive. Live brokers are: [Set()], Assigned replicas are: [List(8, 7, 1)] at kafka.controller.OfflinePartitionLeaderSelector.selectLeader(PartitionLeaderSelector.scala:61) at kafka.controller.PartitionStateMachine.electLeaderForPartition(PartitionStateMachine.scala:336) at kafka.controller.PartitionStateMachine.kafka$controller$PartitionStateMachine$$handleStateChange(PartitionStateMachine.scala:185) at kafka.controller.PartitionStateMachine$$anonfun$triggerOnlinePartitionStateChange$3.apply(PartitionStateMachine.scala:99) at kafka.controller.PartitionStateMachine$$anonfun$triggerOnlinePartitionStateChange$3.apply(PartitionStateMachine.scala:96) at scala.collection.TraversableLike$WithFilter$$anonfun$foreach$1.apply(TraversableLike.scala:743) at scala.collection.mutable.HashMap$$anonfun$foreach$1.apply(HashMap.scala:95) at scala.collection.mutable.HashMap$$anonfun$foreach$1.apply(HashMap.scala:95) at scala.collection.Iterator$class.foreach(Iterator.scala:772) at scala.collection.mutable.HashTable$$anon$1.foreach(HashTable.scala:157) at scala.collection.mutable.HashTable$class.foreachEntry(HashTable.scala:190) at scala.collection.mutable.HashMap.foreachEntry(HashMap.scala:45) at scala.collection.mutable.HashMap.foreach(HashMap.scala:95) at scala.collection.TraversableLike$WithFilter.foreach(TraversableLike.scala:742) at kafka.controller.PartitionStateMachine.triggerOnlinePartitionStateChange(PartitionStateMachine.scala:96) at kafka.controller.PartitionStateMachine.startup(PartitionStateMachine.scala:68) at kafka.controller.KafkaController.onControllerFailover(KafkaController.scala:312) at kafka.controller.KafkaController$$anonfun$1.apply$mcV$sp(KafkaController.scala:162) at kafka.server.ZookeeperLeaderElector.elect(ZookeeperLeaderElector.scala:63) at kafka.server.ZookeeperLeaderElector$LeaderChangeListener$$anonfun$handleDataDeleted$1.apply$mcZ$sp(ZookeeperLeaderElector.scala:123) at kafka.server.ZookeeperLeaderElector$LeaderChangeListener$$anonfun$handleDataDeleted$1.apply(ZookeeperLeaderElector.scala:118) at kafka.server.ZookeeperLeaderElector$LeaderChangeListener$$anonfun$handleDataDeleted$1.apply(ZookeeperLeaderElector.scala:118) at kafka.utils.Utils$.inLock(Utils.scala:538) at kafka.server.ZookeeperLeaderElector$LeaderChangeListener.handleDataDeleted(ZookeeperLeaderElector.scala:118) at org.I0Itec.zkclient.ZkClient$6.run(ZkClient.java:549) at org.I0Itec.zkclient.ZkEventThread.run(ZkEventThread.java:71) Anyways, this morning after sending out the email, I set out to restart all the brokers. I found that 3 brokers were in a hung state. I tried to use the bin/kafka-server-stop.sh script (which is nothing but sending a SIGINT signal), the java process running kafka would not terminate, I then issued a 'kill -SIGTERM xxxxx' for the java process running Kafka, yet the process would not terminate. This happened only on 3 nodes (1 node is running only 1 broker). For the other nodes kafka-server-stop.sh successfully bought down the java process running Kafka. For the three brokers that was not responding to either SIGINT and SIGTERM signal I issued a SIGKILL instead and this, for sure brought down the process. I then restarted brokers on all nodes. After that I again ran the describe topic script. bin/kafka-topics.sh --describe --zookeeper tr-pan-hclstr-08.amers1b. ciscloud:2181/kafka/kafka-clstr-01 --topic wordcount Topic:wordcount PartitionCount:8 ReplicationFactor:3 Configs: Topic: wordcount Partition: 0 Leader: 7 Replicas: 7,6,8 Isr: 6,7,8 Topic: wordcount Partition: 1 Leader: 8 Replicas: 8,7,1 Isr: 1,7,8 Topic: wordcount Partition: 2 Leader: 1 Replicas: 1,8,2 Isr: 1,2,8 Topic: wordcount Partition: 3 Leader: 2 Replicas: 2,1,3 Isr: 1,2,3 Topic: wordcount Partition: 4 Leader: 3 Replicas: 3,2,4 Isr: 2,3,4 Topic: wordcount Partition: 5 Leader: 4 Replicas: 4,3,5 Isr: 3,4,5 Topic: wordcount Partition: 6 Leader: 5 Replicas: 5,4,6 Isr: 4,5,6 Topic: wordcount Partition: 7 Leader: 6 Replicas: 6,5,7 Isr: 5,6,7 Since then it is been running fine. My conclusion is that for some reason (which I don't really understand), 3 brokers were effectively in a hung state and probably caused the broken cluster. Regards, -Jacob On Tue, Oct 14, 2014 at 5:39 PM, Jun Rao <jun...@gmail.com> wrote: > Also, which version of Kafka are you using? > > Thanks, > > Jun > > On Tue, Oct 14, 2014 at 5:31 PM, Jun Rao <jun...@gmail.com> wrote: > > > The following is a bit weird. It indicates no leader for partition 4, > > which is inconsistent with what describe-topic shows. > > > > 2014-10-13 19:02:32,611 WARN [main] kafka.producer.BrokerPartitionInfo: > > Error while fetching metadata partition 4 leader: none > replicas: 3 > > (tr-pan-hclstr-13.amers1b.ciscloud:9092),2 > > (tr-pan-hclstr-12.amers1b.ciscloud:9092),4 > > (tr-pan-hclstr-14.amers1b.ciscloud:9092) isr: isUnderReplicated: > > true for topic partition [wordcount,4]: [class > > kafka.common.LeaderNotAvailableException] > > > > Any error in the controller and the state-change log? Do you see broker 3 > > marked as dead in the controller log? Also, could you check if the broker > > registration in ZK ( > > > https://cwiki.apache.org/confluence/display/KAFKA/Kafka+data+structures+in+Zookeeper > ) > > has the correct host/port? > > > > Thanks, > > > > Jun > > > > On Mon, Oct 13, 2014 at 5:35 PM, Abraham Jacob <abe.jac...@gmail.com> > > wrote: > > > >> Hi All, > >> > >> I have a 8 node Kafka cluster (broker.id - 1..8). On this cluster I > have > >> a > >> topic "wordcount", which was 8 partitions with a replication factor of > 3. > >> > >> So a describe of topic wordcount > >> # bin/kafka-topics.sh --describe --zookeeper > >> tr-pan-hclstr-08.amers1b.ciscloud:2181/kafka/kafka-clstr-01 --topic > >> wordcount > >> > >> > >> Topic:wordcount PartitionCount:8 ReplicationFactor:3 Configs: > >> Topic: wordcount Partition: 0 Leader: 6 Replicas: 7,6,8 > >> Isr: 6,7,8 > >> Topic: wordcount Partition: 1 Leader: 7 Replicas: 8,7,1 > >> Isr: 7 > >> Topic: wordcount Partition: 2 Leader: 8 Replicas: 1,8,2 > >> Isr: 8 > >> Topic: wordcount Partition: 3 Leader: 3 Replicas: 2,1,3 > >> Isr: 3 > >> Topic: wordcount Partition: 4 Leader: 3 Replicas: 3,2,4 > >> Isr: 3,2,4 > >> Topic: wordcount Partition: 5 Leader: 3 Replicas: 4,3,5 > >> Isr: 3,5 > >> Topic: wordcount Partition: 6 Leader: 6 Replicas: 5,4,6 > >> Isr: 6,5 > >> Topic: wordcount Partition: 7 Leader: 6 Replicas: 6,5,7 > >> Isr: 6,5,7 > >> > >> I wrote a simple producer to write to this topic. However when running I > >> get these messages in the logs - > >> > >> 2014-10-13 19:02:32,459 INFO [main] kafka.client.ClientUtils$: Fetching > >> metadata from broker > id:0,host:tr-pan-hclstr-11.amers1b.ciscloud,port:9092 > >> with correlation id 0 for 1 topic(s) Set(wordcount) > >> 2014-10-13 19:02:32,464 INFO [main] kafka.producer.SyncProducer: > Connected > >> to tr-pan-hclstr-11.amers1b.ciscloud:9092 for producing > >> 2014-10-13 19:02:32,551 INFO [main] kafka.producer.SyncProducer: > >> Disconnecting from tr-pan-hclstr-11.amers1b.ciscloud:9092 > >> 2014-10-13 19:02:32,611 WARN [main] kafka.producer.BrokerPartitionInfo: > >> Error while fetching metadata partition 4 leader: none > replicas: > >> 3 > >> (tr-pan-hclstr-13.amers1b.ciscloud:9092),2 > >> (tr-pan-hclstr-12.amers1b.ciscloud:9092),4 > >> (tr-pan-hclstr-14.amers1b.ciscloud:9092) isr: isUnderReplicated: > >> true for topic partition [wordcount,4]: [class > >> kafka.common.LeaderNotAvailableException] > >> 2014-10-13 19:02:33,505 INFO [main] kafka.producer.SyncProducer: > Connected > >> to tr-pan-hclstr-15.amers1b.ciscloud:9092 for producing > >> 2014-10-13 19:02:33,543 WARN [main] > >> kafka.producer.async.DefaultEventHandler: Produce request with > correlation > >> id 20611 failed due to [wordcount,5]: > >> kafka.common.NotLeaderForPartitionException,[wordcount,6]: > >> kafka.common.NotLeaderForPartitionException,[wordcount,7]: > >> kafka.common.NotLeaderForPartitionException > >> 2014-10-13 19:02:33,694 INFO [main] kafka.producer.SyncProducer: > Connected > >> to tr-pan-hclstr-18.amers1b.ciscloud:9092 for producing > >> 2014-10-13 19:02:33,725 WARN [main] > >> kafka.producer.async.DefaultEventHandler: Produce request with > correlation > >> id 20612 failed due to [wordcount,0]: > >> kafka.common.NotLeaderForPartitionException > >> 2014-10-13 19:02:33,861 INFO [main] kafka.producer.SyncProducer: > Connected > >> to tr-pan-hclstr-11.amers1b.ciscloud:9092 for producing > >> 2014-10-13 19:02:33,983 WARN [main] > >> kafka.producer.async.DefaultEventHandler: Failed to send data since > >> partitions [wordcount,4] don't have a leader > >> > >> > >> Obviously something is terribly wrong... I am quite new to Kafka, hence > >> these messages don't make any sense to me, except for the fact that it > is > >> telling me that some of the partitions don't have any leader. > >> > >> Could somebody be kind enough to explain the above message? > >> > >> A few more questions - > >> > >> (1) How does one get into this state? > >> (2) How can I get out of this state? > >> (3) I have set auto.leader.rebalance.enable=true on all brokers. > Shouldn't > >> the partitions be balanced across all the brokers? > >> (4) I can see that the Kafka service are running on all 8 nodes. (I used > >> ps ax -o "pid pgid args" and I can see under the kafka Java process). > >> (5) Is there a way I can force a re-balance? > >> > >> > >> > >> Regards, > >> Jacob > >> > >> > >> > >> -- > >> ~ > >> > > > > > -- ~