切换 leader
作者:互联网
场景: 3 节点集群 (b1, b2, b3),分区 tp1 的 isr[1, 2, 3],leader 是 1,现在希望把 tp1 的 leader 切换为 3,怎么操作?
1. 通过 zk 客户端,修改 zk 上 tp1 的 isr 列表为 [3, 2, 1]
2. 执行命令行 kafka-preferred-replica-election.sh,把需要修改 leader 的分区信息写入到 zk 的 /admin/preferred_replica_election 节点
// kafka.admin.PreferredReplicaLeaderElectionCommand#writePreferredReplicaElectionData def writePreferredReplicaElectionData(zkClient: KafkaZkClient, partitionsUndergoingPreferredReplicaElection: Set[TopicPartition]) { try { zkClient.createPreferredReplicaElection(partitionsUndergoingPreferredReplicaElection.toSet) println("Created preferred replica election path with %s".format(partitionsUndergoingPreferredReplicaElection.mkString(","))) } catch { case _: NodeExistsException => throw new AdminOperationException("Preferred replica leader election currently in progress for " + "%s. Aborting operation".format(zkClient.getPreferredReplicaElection.mkString(","))) case e2: Throwable => throw new AdminOperationException(e2.toString) } }
3. KafkaController 监听 /admin/preferred_replica_election 节点,重新选举 leader,取 isr 中第一个副本为 leader,发送 LeaderAndIsrRequest 请求给其他 broker,通知他们转变副本角色
// kafka.controller.KafkaController.PreferredReplicaLeaderElection case object PreferredReplicaLeaderElection extends ControllerEvent { override def state: ControllerState = ControllerState.ManualLeaderBalance override def process(): Unit = { if (!isActive) return // We need to register the watcher if the path doesn't exist in order to detect future preferred replica // leader elections and we get the `path exists` check for free if (zkClient.registerZNodeChangeHandlerAndCheckExistence(preferredReplicaElectionHandler)) { val partitions = zkClient.getPreferredReplicaElection val partitionsForTopicsToBeDeleted = partitions.filter(p => topicDeletionManager.isTopicQueuedUpForDeletion(p.topic)) if (partitionsForTopicsToBeDeleted.nonEmpty) { error(s"Skipping preferred replica election for partitions $partitionsForTopicsToBeDeleted since the " + "respective topics are being deleted") } onPreferredReplicaElection(partitions -- partitionsForTopicsToBeDeleted) } } } // kafka.controller.KafkaController#onPreferredReplicaElection private def onPreferredReplicaElection(partitions: Set[TopicPartition], isTriggeredByAutoRebalance: Boolean = false) { info(s"Starting preferred replica leader election for partitions ${partitions.mkString(",")}") try { partitionStateMachine.handleStateChanges(partitions.toSeq, OnlinePartition, Option(PreferredReplicaPartitionLeaderElectionStrategy)) } catch { case e: Throwable => error(s"Error completing preferred replica leader election for partitions ${partitions.mkString(",")}", e) } finally { removePartitionsFromPreferredReplicaElection(partitions, isTriggeredByAutoRebalance) } }
标签:切换,preferred,replica,election,zkClient,leader,partitions 来源: https://www.cnblogs.com/allenwas3/p/13173348.html