I have a kafka cluster with 3 brokers. I have started facing issues lately with brokers going out of the cluster and producrs/consumers throwing leader not available errors.
On examining the logs I see following sequence of events:
//Lots of replica fetcher threads starting/stopping
[2017-10-09 14:48:50,600] INFO [ReplicaFetcherManager on broker 6] Removed fetcher for partitions
[2017-10-09 14:48:50,608] INFO [ReplicaFetcherThread-0-7], Shutting down (kafka.server.ReplicaFetcherThread)
[2017-10-09 14:48:50,918] INFO [ReplicaFetcherThread-0-7], Stopped (kafka.server.ReplicaFetcherThread)
[2017-10-09 14:48:50,918] INFO [ReplicaFetcherThread-0-7], Shutdown completed (kafka.server.ReplicaFetcherThread)
//continuously Expanding/Shrinking ISR
[2017-10-09 14:48:51,037] INFO Partition [__consumer_offsets,8] on broker 6: Expanding ISR for partition __consumer_offsets-8 from 6,8 to 6,8,7 (kafka.cluster.Partition)
[2017-10-09 14:48:51,038] INFO Partition [__consumer_offsets,35] on broker 6: Expanding ISR for partition __consumer_offsets-35 from 6,8 to 6,8,7 (kafka.cluster.Partition)
[2017-10-09 14:49:01,702] INFO Partition [t1,1] on broker 6: Shrinking ISR for partition [t1,1] from 6,7 to 6 (kafka.cluster.Partition)
[2017-10-09 14:49:01,702] INFO Partition [__consumer_offsets,41] on broker 6: Shrinking ISR for partition [__consumer_offsets,41] from 6,8,7 to 6,8 (kafka.cluster.Partition)
//Reregisteration of broker and leader reelection
[2017-10-09 14:51:54,380] INFO re-registering broker info in ZK for broker 6
[2017-10-09 14:51:54,405] INFO New leader is 7 (kafka.server.ZookeeperLeaderElector$LeaderChangeListener)
//ControllerMovedException errors
[2017-10-09 14:56:39,746] ERROR [KafkaApi-6] Error when handling request.. org.apache.kafka.common.errors.ControllerMovedException: Broker 6 received update metadata request with correlation id 59 from an old controlle
r 7 with epoch 301. Latest known controller epoch is 302
[2017-10-09 14:57:59,210] INFO re-registering broker info in ZK for broker 6 (kafka.server.KafkaHealthcheck$SessionExpireListener)
[2017-10-09 14:57:59,210] INFO Creating /brokers/ids/6 (is it secure? false) (kafka.utils.ZKCheckedEphemeral)
[2017-10-09 14:57:59,213] INFO Result of znode creation is: OK (kafka.utils.ZKCheckedEphemeral)
[2017-10-09 14:57:59,213] INFO Registered broker 6 at path /brokers/ids/6 with addresses: EndPoint(kafka03,9092,ListenerName(PLAIN
TEXT),PLAINTEXT) (kafka.utils.ZkUtils)
[2017-10-09 14:57:59,213] INFO done re-registering broker (kafka.server.KafkaHealthcheck$SessionExpireListener)
[2017-10-09 14:57:59,213] INFO Subscribing to /brokers/topics path to watch for new topics (kafka.server.KafkaHealthcheck$SessionExpireListener
)
[2017-10-09 14:57:59,224] INFO New leader is 7 (kafka.server.ZookeeperLeaderElector$LeaderChangeListener)
[2017-10-09 14:58:11,697] INFO Partition [testing1,2] on broker 6: Shrinking ISR for partition [testing1,2] from 6,8 to 6 (kafka.cluster.Partit
ion)
[2017-10-09 14:58:11,700] INFO Partition [testing1,2] on broker 6: Cached zkVersion [199] not equal to that in zookeeper, skip updating ISR (ka
fka.cluster.Partition)
Then these errors occur in a loop, and cluster cannot recover
[2017-10-09 16:17:26,769] INFO Partition [__consumer_offsets,14] on broker 6: Shrinking ISR for partition [__consumer_offsets,14] from 7,6,8 to 7,6 (kafka.cluster.Partition)
[2017-10-09 16:17:26,771] INFO Partition [__consumer_offsets,14] on broker 6: Cached zkVersion [306] not equal to that in zookeeper, skip updating ISR (kafka.cluster.Partition)
On the clients, I receive Leader not available error.
Its not clear why the cluster is entering this invalid state.. any ideas?
This issue is known and tracked in KAFKA-2729 but not solved till now. This happens as far as I know on networks with big delays due to max traffic or some short network outages in a small timeframe. The only solution (afaik) is to restart all brokers.
kill the current controller, then there will be another controller elected.
restart the previous controller you killed at step 1
partiton state will be fixed
来源：https://stackoverflow.com/questions/46644764/kafka-cached-zkversion-not-equal-to-that-in-zookeeper-broker-not-recovering