当节点启动并运行时，Kafka主题具有带有Leader = -1（Kafka Leader Election）的分区

Question

我有3个成员的kafka-cluster设置， __consumer_offsets主题有50个分区。

以下是describe命令的结果：

root@kafka-cluster-0:~# kafka-topics.sh --zookeeper localhost:2181 --describe
Topic:__consumer_offsets    PartitionCount:50   ReplicationFactor:1 Configs:segment.bytes=104857600,cleanup.policy=compact,compression.type=producer
    Topic: __consumer_offsets   Partition: 0    Leader: 1   Replicas: 1 Isr: 1
    Topic: __consumer_offsets   Partition: 1    Leader: -1  Replicas: 2 Isr: 2
    Topic: __consumer_offsets   Partition: 2    Leader: 0   Replicas: 0 Isr: 0
    Topic: __consumer_offsets   Partition: 3    Leader: 1   Replicas: 1 Isr: 1
    Topic: __consumer_offsets   Partition: 4    Leader: -1  Replicas: 2 Isr: 2
    Topic: __consumer_offsets   Partition: 5    Leader: 0   Replicas: 0 Isr: 0
    ...
    ...

成员是节点0、1和2。

显而易见， 副本= 2中的分区没有为其设置领导者 ，并且他们的领导者= -1

我想知道是什么原因导致了这个问题，所以我重新启动了第二个成员kafka服务，但我从没想过它会产生这种副作用。

同样，现在，所有节点都已经运行了几个小时，这是ls broker / ids的结果：

/home/kafka/bin/zookeeper-shell.sh localhost:2181 <<< "ls /brokers/ids"
Connecting to localhost:2181
Welcome to ZooKeeper!
JLine support is disabled

WATCHER::

WatchedEvent state:SyncConnected type:None path:null
[0, 1, 2]

另外，集群中有很多主题， 节点2并不是其中任何一个的领导者，并且只要它只有数据（replication-factor = 1，并在该节点上托管分区）的任何地方， leader = -1都是显而易见的从下面。

Here, node 2 is in the ISR, but never a leader, since replication-factor=2.
Topic:upstream-t2   PartitionCount:20   ReplicationFactor:2 Configs:retention.ms=172800000,retention.bytes=536870912
    Topic: upstream-t2  Partition: 0    Leader: 1   Replicas: 1,2   Isr: 1,2
    Topic: upstream-t2  Partition: 1    Leader: 0   Replicas: 2,0   Isr: 0
    Topic: upstream-t2  Partition: 2    Leader: 0   Replicas: 0,1   Isr: 0
    Topic: upstream-t2  Partition: 3    Leader: 0   Replicas: 1,0   Isr: 0
    Topic: upstream-t2  Partition: 4    Leader: 1   Replicas: 2,1   Isr: 1,2
    Topic: upstream-t2  Partition: 5    Leader: 0   Replicas: 0,2   Isr: 0
    Topic: upstream-t2  Partition: 6    Leader: 1   Replicas: 1,2   Isr: 1,2


Here, node 2 is the only partition some chunks of data are hosted on, but leader=-1.
Topic:upstream-t20  PartitionCount:10   ReplicationFactor:1 Configs:retention.ms=172800000,retention.bytes=536870912
    Topic: upstream-t20 Partition: 0    Leader: 1   Replicas: 1 Isr: 1
    Topic: upstream-t20 Partition: 1    Leader: -1  Replicas: 2 Isr: 2
    Topic: upstream-t20 Partition: 2    Leader: 0   Replicas: 0 Isr: 0
    Topic: upstream-t20 Partition: 3    Leader: 1   Replicas: 1 Isr: 1
    Topic: upstream-t20 Partition: 4    Leader: -1  Replicas: 2 Isr: 2

非常感谢您提供有关如何修复未当选领导人的帮助。

同样，很高兴知道这可能会对我的经纪人的行为产生任何潜在的影响。

编辑-

Kafka版本：1.1.0（2.12-1.1.0）可用空间，例如800GB的可用磁盘。 日志文件非常正常，在节点2上，下面是日志文件的最后10行。 请让我知道我是否有特别需要寻找的东西。

[2018-12-18 10:31:43,828] INFO [Log partition=upstream-t14-1, dir=/var/lib/kafka] Rolled new log segment at offset 79149636 in 2 ms. (kafka.log.Log)
[2018-12-18 10:32:03,622] INFO Updated PartitionLeaderEpoch. New: {epoch:10, offset:6435}, Current: {epoch:8, offset:6386} for Partition: upstream-t41-8. Cache now contains 7 entries. (kafka.server.epoch.LeaderEpochFileCache)
[2018-12-18 10:32:03,693] INFO Updated PartitionLeaderEpoch. New: {epoch:10, offset:6333}, Current: {epoch:8, offset:6324} for Partition: upstream-t41-3. Cache now contains 7 entries. (kafka.server.epoch.LeaderEpochFileCache)
[2018-12-18 10:38:38,554] INFO [GroupMetadataManager brokerId=2] Removed 0 expired offsets in 0 milliseconds. (kafka.coordinator.group.GroupMetadataManager)
[2018-12-18 10:40:04,831] INFO Updated PartitionLeaderEpoch. New: {epoch:10, offset:6354}, Current: {epoch:8, offset:6340} for Partition: upstream-t41-9. Cache now contains 7 entries. (kafka.server.epoch.LeaderEpochFileCache)
[2018-12-18 10:48:38,554] INFO [GroupMetadataManager brokerId=2] Removed 0 expired offsets in 0 milliseconds. (kafka.coordinator.group.GroupMetadataManager)
[2018-12-18 10:58:38,554] INFO [GroupMetadataManager brokerId=2] Removed 0 expired offsets in 0 milliseconds. (kafka.coordinator.group.GroupMetadataManager)
[2018-12-18 11:05:50,770] INFO [ProducerStateManager partition=upstream-t4-17] Writing producer snapshot at offset 3086815 (kafka.log.ProducerStateManager)
[2018-12-18 11:05:50,772] INFO [Log partition=upstream-t4-17, dir=/var/lib/kafka] Rolled new log segment at offset 3086815 in 2 ms. (kafka.log.Log)
[2018-12-18 11:07:16,634] INFO [ProducerStateManager partition=upstream-t4-11] Writing producer snapshot at offset 3086497 (kafka.log.ProducerStateManager)
[2018-12-18 11:07:16,635] INFO [Log partition=upstream-t4-11, dir=/var/lib/kafka] Rolled new log segment at offset 3086497 in 1 ms. (kafka.log.Log)
[2018-12-18 11:08:15,803] INFO [ProducerStateManager partition=upstream-t4-5] Writing producer snapshot at offset 3086616 (kafka.log.ProducerStateManager)
[2018-12-18 11:08:15,804] INFO [Log partition=upstream-t4-5, dir=/var/lib/kafka] Rolled new log segment at offset 3086616 in 1 ms. (kafka.log.Log)
[2018-12-18 11:08:38,554] INFO [GroupMetadataManager brokerId=2] Removed 0 expired offsets in 0 milliseconds. (kafka.coordinator.group.GroupMetadataManager)

编辑2 ----

好吧，我已经停止了领导者Zookeeper实例 ，现在第二个Zookeeper实例当选为领导者！ 有了这个，未选择的领导者问题现在就解决了！

我也不知道可能出了什么问题，因此非常欢迎任何有关“ 为什么更换动物园管理员领导者解决未选定的领导者问题 ”的想法！

谢谢！

Answer 1

尽管根本原因尚未查明，但询问者似乎确实找到了解决方案：

我已经停止了领导者Zookeeper实例，现在将第二个Zookeeper实例选举为领导者！ 有了这个，未选择的领导者问题现在就解决了！