众所周知 kafka 的 topic 可以使用 --replication-factor 数和 partitions 数来保证服务的高可用性
问题发现
查了很多资料后发现是kafka本身的 topic __consumer_offsets 搞的鬼。
问题分析
在高版本的kakfa中，消费者的offset偏移量会保存在kafka自身一个叫做__consumer_offsets的topic中，由于这个topic是由kafka本身默认创建，所以副本数会配置文件中指定的默认副本数，一般为1。
查看副本分区情况一般为：
./kafka-topics.sh --zookeeper localhost:2181 --describe __consumer_offsets Topic:__consumer_offsets PartitionCount:50 ReplicationFactor:1 Configs:segment.bytes=104857600,cleanup.policy=compact,compression.type=producer Topic: __consumer_offsets Partition: 0 Leader: 3 Replicas: 3 Isr: 3 Topic: __consumer_offsets Partition: 1 Leader: 1 Replicas: 1 Isr: 1 Topic: __consumer_offsets Partition: 2 Leader: 2 Replicas: 2 Isr: 2 Topic: __consumer_offsets Partition: 3 Leader: 3 Replicas: 3 Isr: 3 Topic: __consumer_offsets Partition: 4 Leader: 1 Replicas: 1 Isr: 1 Topic: __consumer_offsets Partition: 5 Leader: 2 Replicas: 2 Isr: 2 Topic: __consumer_offsets Partition: 6 Leader: 3 Replicas: 3 Isr: 3 Topic: __consumer_offsets Partition: 7 Leader: 1 Replicas: 1 Isr: 1 Topic: __consumer_offsets Partition: 8 Leader: 2 Replicas: 2 Isr: 2 Topic: __consumer_offsets Partition: 9 Leader: 3 Replicas: 3 Isr: 3 Topic: __consumer_offsets Partition: 10 Leader: 1 Replicas: 1 Isr: 1 Topic: __consumer_offsets Partition: 11 Leader: 2 Replicas: 2 Isr: 2 Topic: __consumer_offsets Partition: 12 Leader: 3 Replicas: 3 Isr: 3 Topic: __consumer_offsets Partition: 13 Leader: 1 Replicas: 1 Isr: 1 Topic: __consumer_offsets Partition: 14 Leader: 2 Replicas: 2 Isr: 2 Topic: __consumer_offsets Partition: 15 Leader: 3 Replicas: 3 Isr: 3 Topic: __consumer_offsets Partition: 16 Leader: 1 Replicas: 1 Isr: 1 Topic: __consumer_offsets Partition: 17 Leader: 2 Replicas: 2 Isr: 2 Topic: __consumer_offsets Partition: 18 Leader: 3 Replicas: 3 Isr: 3 Topic: __consumer_offsets Partition: 19 Leader: 1 Replicas: 1 Isr: 1 Topic: __consumer_offsets Partition: 20 Leader: 2 Replicas: 2 Isr: 2 Topic: __consumer_offsets Partition: 21 Leader: 3 Replicas: 3 Isr: 3 Topic: __consumer_offsets Partition: 22 Leader: 1 Replicas: 1 Isr: 1 Topic: __consumer_offsets Partition: 23 Leader: 2 Replicas: 2 Isr: 2 Topic: __consumer_offsets Partition: 24 Leader: 3 Replicas: 3 Isr: 3 Topic: __consumer_offsets Partition: 25 Leader: 1 Replicas: 1 Isr: 1 Topic: __consumer_offsets Partition: 26 Leader: 2 Replicas: 2 Isr: 2 Topic: __consumer_offsets Partition: 27 Leader: 3 Replicas: 3 Isr: 3 Topic: __consumer_offsets Partition: 28 Leader: 1 Replicas: 1 Isr: 1 Topic: __consumer_offsets Partition: 29 Leader: 2 Replicas: 2 Isr: 2 Topic: __consumer_offsets Partition: 30 Leader: 3 Replicas: 3 Isr: 3 Topic: __consumer_offsets Partition: 31 Leader: 1 Replicas: 1 Isr: 1 Topic: __consumer_offsets Partition: 32 Leader: 2 Replicas: 2 Isr: 2 Topic: __consumer_offsets Partition: 33 Leader: 3 Replicas: 3 Isr: 3 Topic: __consumer_offsets Partition: 34 Leader: 1 Replicas: 1 Isr: 1 Topic: __consumer_offsets Partition: 35 Leader: 2 Replicas: 2 Isr: 2 Topic: __consumer_offsets Partition: 36 Leader: 3 Replicas: 3 Isr: 3 Topic: __consumer_offsets Partition: 37 Leader: 1 Replicas: 1 Isr: 1 Topic: __consumer_offsets Partition: 38 Leader: 2 Replicas: 2 Isr: 2 Topic: __consumer_offsets Partition: 39 Leader: 3 Replicas: 3 Isr: 3 Topic: __consumer_offsets Partition: 40 Leader: 1 Replicas: 1 Isr: 1 Topic: __consumer_offsets Partition: 41 Leader: 2 Replicas: 2 Isr: 2 Topic: __consumer_offsets Partition: 42 Leader: 3 Replicas: 3 Isr: 3 Topic: __consumer_offsets Partition: 43 Leader: 1 Replicas: 1 Isr: 1 Topic: __consumer_offsets Partition: 44 Leader: 2 Replicas: 2 Isr: 2 Topic: __consumer_offsets Partition: 45 Leader: 3 Replicas: 3 Isr: 3 Topic: __consumer_offsets Partition: 46 Leader: 1 Replicas: 1 Isr: 1 Topic: __consumer_offsets Partition: 47 Leader: 2 Replicas: 2 Isr: 2 Topic: __consumer_offsets Partition: 48 Leader: 3 Replicas: 3 Isr: 3 Topic: __consumer_offsets Partition: 49 Leader: 1 Replicas: 1 Isr: 1
50个分区，每个分区1个副本。
50个分区是遍布在3台broker的，这就导致如果有其中一台broker服务挂了，在其broker的所有Partition将不能正常使用，就导致此Partition的消费者不知道自己的offset偏移量，就导致无法正常消费。
问题解决
方法1
由于现在kafka已经开始正常提供服务，所以只能动态修改：
先准备分区副本规划 json 文件
vim /data/vfan/consumer.json
{ "version": 1, "partitions": [ { "topic": "__consumer_offsets", "partition": 0, "replicas": [ 1, 2, 3 ] }, { "topic": "__consumer_offsets", "partition": 1, "replicas": [ 2, 1, 3 ] }, { "topic": "__consumer_offsets", "partition": 2, "replicas": [ 3, 2, 1 ] }, { "topic": "__consumer_offsets", "partition": 3, "replicas": [ 1, 2, 3 ] }, { "topic": "__consumer_offsets", "partition": 4, "replicas": [ 2, 1, 3 ] }, { "topic": "__consumer_offsets", "partition": 5, "replicas": [ 3, 2, 1 ] }, { "topic": "__consumer_offsets", "partition": 6, "replicas": [ 1, 2, 3 ] }, { "topic": "__consumer_offsets", "partition": 7, "replicas": [ 2, 1, 3 ] }, { "topic": "__consumer_offsets", "partition": 8, "replicas": [ 3, 2, 1 ] }, { "topic": "__consumer_offsets", "partition": 9, "replicas": [ 1, 2, 3 ] }, { "topic": "__consumer_offsets", "partition": 10, "replicas": [ 2, 1, 3 ] }, { "topic": "__consumer_offsets", "partition": 11, "replicas": [ 3, 1, 2 ] }, { "topic": "__consumer_offsets", "partition": 12, "replicas": [ 2, 1, 3 ] }, { "topic": "__consumer_offsets", "partition": 13, "replicas": [ 1, 2, 3 ] }, { "topic": "__consumer_offsets", "partition": 14, "replicas": [ 1, 2, 3 ] }, { "topic": "__consumer_offsets", "partition": 15, "replicas": [ 2, 1, 3 ] }, { "topic": "__consumer_offsets", "partition": 16, "replicas": [ 3, 2, 1 ] }, { "topic": "__consumer_offsets", "partition": 17, "replicas": [ 1, 2, 3 ] }, { "topic": "__consumer_offsets", "partition": 18, "replicas": [ 2, 1, 3 ] }, { "topic": "__consumer_offsets", "partition": 19, "replicas": [ 3, 2, 1 ] }, { "topic": "__consumer_offsets", "partition": 20, "replicas": [ 1, 2, 3 ] }, { "topic": "__consumer_offsets", "partition": 21, "replicas": [ 2, 1, 3 ] }, { "topic": "__consumer_offsets", "partition": 22, "replicas": [ 3, 2, 1 ] }, { "topic": "__consumer_offsets", "partition": 23, "replicas": [ 1, 2, 3 ] }, { "topic": "__consumer_offsets", "partition": 24, "replicas": [ 2, 1, 3 ] }, { "topic": "__consumer_offsets", "partition": 25, "replicas": [ 3, 2, 1 ] }, { "topic": "__consumer_offsets", "partition": 26, "replicas": [ 1, 2, 3 ] }, { "topic": "__consumer_offsets", "partition": 27, "replicas": [ 2, 1, 3 ] }, { "topic": "__consumer_offsets", "partition": 28, "replicas": [ 3, 2, 1 ] }, { "topic": "__consumer_offsets", "partition": 29, "replicas": [ 1, 2, 3 ] }, { "topic": "__consumer_offsets", "partition": 30, "replicas": [ 2, 1, 3 ] }, { "topic": "__consumer_offsets", "partition": 31, "replicas": [ 3, 2, 1 ] }, { "topic": "__consumer_offsets", "partition": 32, "replicas": [ 1, 2, 3 ] }, { "topic": "__consumer_offsets", "partition": 33, "replicas": [ 2, 1, 3 ] }, { "topic": "__consumer_offsets", "partition": 34, "replicas": [ 3, 2, 1 ] }, { "topic": "__consumer_offsets", "partition": 35, "replicas": [ 1, 2, 3 ] }, { "topic": "__consumer_offsets", "partition": 36, "replicas": [ 2, 1, 3 ] }, { "topic": "__consumer_offsets", "partition": 37, "replicas": [ 3, 2, 1 ] }, { "topic": "__consumer_offsets", "partition": 38, "replicas": [ 1, 2, 3 ] }, { "topic": "__consumer_offsets", "partition": 39, "replicas": [ 2, 1, 3 ] }, { "topic": "__consumer_offsets", "partition": 40, "replicas": [ 3, 2, 1 ] }, { "topic": "__consumer_offsets", "partition": 41, "replicas": [ 1, 2, 3 ] }, { "topic": "__consumer_offsets", "partition": 42, "replicas": [ 2, 1, 3 ] }, { "topic": "__consumer_offsets", "partition": 43, "replicas": [ 3, 2, 1 ] }, { "topic": "__consumer_offsets", "partition": 44, "replicas": [ 1, 2, 3 ] }, { "topic": "__consumer_offsets", "partition": 45, "replicas": [ 2, 1, 3 ] }, { "topic": "__consumer_offsets", "partition": 46, "replicas": [ 3, 2, 1 ] }, { "topic": "__consumer_offsets", "partition": 47, "replicas": [ 1, 2, 3 ] }, { "topic": "__consumer_offsets", "partition": 48, "replicas": [ 2, 1, 3 ] }, { "topic": "__consumer_offsets", "partition": 49, "replicas": [ 3, 2, 1 ] } ] }
各 replicas 所在的 broker id可以自定义修改，但不能有重复的broker
开始执行变更
./kafka-reassign-partitions.sh --zookeeper localhost:2181 --reassignment-json-file /data/vfan/consumer.json --execute
校验变更是否完成
./kafka-reassign-partitions.sh --zookeeper localhost:2181 --reassignment-json-file /data/vfan/consumer.json --verify
检查变更后效果
./kafka-topics.sh --zookeeper localhost:2181 --describe --topic __consumer_offsets Topic:__consumer_offsets PartitionCount:50 ReplicationFactor:3 Configs:segment.bytes=104857600,cleanup.policy=compact,compression.type=producer Topic: __consumer_offsets Partition: 0 Leader: 1 Replicas: 1,2,3 Isr: 3,2,1 Topic: __consumer_offsets Partition: 1 Leader: 2 Replicas: 2,1,3 Isr: 1,2,3 Topic: __consumer_offsets Partition: 2 Leader: 3 Replicas: 3,2,1 Isr: 2,3,1 Topic: __consumer_offsets Partition: 3 Leader: 1 Replicas: 1,2,3 Isr: 3,1,2 Topic: __consumer_offsets Partition: 4 Leader: 2 Replicas: 2,1,3 Isr: 1,2,3 Topic: __consumer_offsets Partition: 5 Leader: 3 Replicas: 3,2,1 Isr: 2,3,1 Topic: __consumer_offsets Partition: 6 Leader: 1 Replicas: 1,2,3 Isr: 3,2,1 Topic: __consumer_offsets Partition: 7 Leader: 2 Replicas: 2,1,3 Isr: 1,2,3 Topic: __consumer_offsets Partition: 8 Leader: 3 Replicas: 3,2,1 Isr: 2,1,3 Topic: __consumer_offsets Partition: 9 Leader: 1 Replicas: 1,2,3 Isr: 3,1,2 Topic: __consumer_offsets Partition: 10 Leader: 2 Replicas: 2,1,3 Isr: 1,2,3 Topic: __consumer_offsets Partition: 11 Leader: 3 Replicas: 3,1,2 Isr: 2,3,1 Topic: __consumer_offsets Partition: 12 Leader: 2 Replicas: 2,1,3 Isr: 3,2,1 Topic: __consumer_offsets Partition: 13 Leader: 1 Replicas: 1,2,3 Isr: 1,2,3 Topic: __consumer_offsets Partition: 14 Leader: 1 Replicas: 1,2,3 Isr: 2,3,1 Topic: __consumer_offsets Partition: 15 Leader: 2 Replicas: 2,1,3 Isr: 3,1,2 Topic: __consumer_offsets Partition: 16 Leader: 3 Replicas: 3,2,1 Isr: 1,2,3 Topic: __consumer_offsets Partition: 17 Leader: 1 Replicas: 1,2,3 Isr: 2,3,1 Topic: __consumer_offsets Partition: 18 Leader: 2 Replicas: 2,1,3 Isr: 3,1,2 Topic: __consumer_offsets Partition: 19 Leader: 3 Replicas: 3,2,1 Isr: 1,3,2 Topic: __consumer_offsets Partition: 20 Leader: 1 Replicas: 1,2,3 Isr: 2,3,1 Topic: __consumer_offsets Partition: 21 Leader: 2 Replicas: 2,1,3 Isr: 3,1,2 Topic: __consumer_offsets Partition: 22 Leader: 3 Replicas: 3,2,1 Isr: 1,2,3 Topic: __consumer_offsets Partition: 23 Leader: 1 Replicas: 1,2,3 Isr: 2,1,3 Topic: __consumer_offsets Partition: 24 Leader: 2 Replicas: 2,1,3 Isr: 3,1,2 Topic: __consumer_offsets Partition: 25 Leader: 3 Replicas: 3,2,1 Isr: 1,2,3 Topic: __consumer_offsets Partition: 26 Leader: 1 Replicas: 1,2,3 Isr: 2,3,1 Topic: __consumer_offsets Partition: 27 Leader: 2 Replicas: 2,1,3 Isr: 3,1,2 Topic: __consumer_offsets Partition: 28 Leader: 3 Replicas: 3,2,1 Isr: 1,2,3 Topic: __consumer_offsets Partition: 29 Leader: 1 Replicas: 1,2,3 Isr: 2,3,1 Topic: __consumer_offsets Partition: 30 Leader: 2 Replicas: 2,1,3 Isr: 3,1,2 Topic: __consumer_offsets Partition: 31 Leader: 3 Replicas: 3,2,1 Isr: 1,2,3 Topic: __consumer_offsets Partition: 32 Leader: 1 Replicas: 1,2,3 Isr: 2,3,1 Topic: __consumer_offsets Partition: 33 Leader: 2 Replicas: 2,1,3 Isr: 3,1,2 Topic: __consumer_offsets Partition: 34 Leader: 3 Replicas: 3,2,1 Isr: 1,2,3 Topic: __consumer_offsets Partition: 35 Leader: 1 Replicas: 1,2,3 Isr: 2,1,3 Topic: __consumer_offsets Partition: 36 Leader: 2 Replicas: 2,1,3 Isr: 3,1,2 Topic: __consumer_offsets Partition: 37 Leader: 3 Replicas: 3,2,1 Isr: 1,3,2 Topic: __consumer_offsets Partition: 38 Leader: 1 Replicas: 1,2,3 Isr: 2,3,1 Topic: __consumer_offsets Partition: 39 Leader: 2 Replicas: 2,1,3 Isr: 3,2,1 Topic: __consumer_offsets Partition: 40 Leader: 3 Replicas: 3,2,1 Isr: 1,2,3 Topic: __consumer_offsets Partition: 41 Leader: 1 Replicas: 1,2,3 Isr: 2,1,3 Topic: __consumer_offsets Partition: 42 Leader: 2 Replicas: 2,1,3 Isr: 3,1,2 Topic: __consumer_offsets Partition: 43 Leader: 3 Replicas: 3,2,1 Isr: 1,2,3 Topic: __consumer_offsets Partition: 44 Leader: 1 Replicas: 1,2,3 Isr: 2,3,1 Topic: __consumer_offsets Partition: 45 Leader: 2 Replicas: 2,1,3 Isr: 3,2,1 Topic: __consumer_offsets Partition: 46 Leader: 3 Replicas: 3,2,1 Isr: 1,2,3 Topic: __consumer_offsets Partition: 47 Leader: 1 Replicas: 1,2,3 Isr: 2,1,3 Topic: __consumer_offsets Partition: 48 Leader: 2 Replicas: 2,1,3 Isr: 3,2,1 Topic: __consumer_offsets Partition: 49 Leader: 3 Replicas: 3,2,1 Isr: 1,2,3
副本数已经成为三个并分布在三个broker中，实现高可用。
方法2
直接在kafka服务启动前，修改系统创建topic默认副本分区参数
num.partitions=3 ;当topic不存在系统自动创建时的分区数 default.replication.factor=3 ;当topic不存在系统自动创建时的副本数 offsets.topic.replication.factor=3 ；表示kafka的内部topic consumer_offsets副本数，默认为1
设置完毕后，启动 zk kafka，随后测试生产 消费
## 生产 ./kafka-console-producer.sh --broker-list localhost:9092 --topic test ## 消费，--from-beginning参数表示从头开始 ./kafka-console-consumer.sh --bootstrap-server localhost:9092 --topic test --from-beginning
查看系统生成的topic 分区及副本数
## test ./kafka-topics.sh --zookeeper localhost:2181 --describe --topic test Topic:test PartitionCount:3 ReplicationFactor:3 Configs: ## __consumer_offsets ./kafka-topics.sh --zookeeper localhost:2181 --describe --topic __consumer_offsets Topic:__consumer_offsets PartitionCount:50 ReplicationFactor:3 Configs:segment.bytes=104857600,cleanup.policy=compact,compression.type=producer
系统自动生成的topic也都已实现高可用