参考官网site:

http://kafka.apache.org/documentation.html#basic_ops_cluster_expansion

https://cwiki.apache.org/confluence/display/KAFKA/Replication+tools#Replicationtools-6.ReassignPartitionsTool

说明:

当我们对kafka集群扩容时，需要满足2点要求:

1. 将指定topic迁移到集群内新增的node上。
2. 将topic的指定partition迁移到新增的node上。

1. 迁移topic到新增的node上

假如现在一个kafka集群运行三个broker，broker.id依次为101,102,103,后来由于业务数据突然暴增，需要新增三个broker,broker.id依次为104,105,106.目的是要把push-token-topic迁移到新增node上。

1、脚本migration-push-token-topic.json文件内容如下:

2、执行脚本如下所示:

生成分配partitions的json脚本 备份恢复使用：

Current partition replica assignment

{"version":1,"partitions":[{"topic":"cluster-switch-topic","partition":10,"replicas":[8]},{"topic":"cluster-switch-topic","partition":5,"replicas":[4]},{"topic":"cluster-switch-topic","partition":3,"replicas":[5]},{"topic":"cluster-switch-topic","partition":4,"replicas":[5]},{"topic":"cluster-switch-topic","partition":9,"replicas":[5]},{"topic":"cluster-switch-topic","partition":1,"replicas":[5]},{"topic":"cluster-switch-topic","partition":11,"replicas":[4]},{"topic":"cluster-switch-topic","partition":7,"replicas":[5]},{"topic":"cluster-switch-topic","partition":2,"replicas":[4]},{"topic":"cluster-switch-topic","partition":0,"replicas":[4]},{"topic":"cluster-switch-topic","partition":6,"replicas":[4]},{"topic":"cluster-switch-topic","partition":8,"replicas":[4]}]}

重新分配parttions的json脚本如下：

migration-topic-cluster-switch-topic.json

{"version":1,"partitions":[{"topic":"cluster-switch-topic","partition":10,"replicas":[5]},{"topic":"cluster-switch-topic","partition":5,"replicas":[4]},{"topic":"cluster-switch-topic","partition":4,"replicas":[5]},{"topic":"cluster-switch-topic","partition":3,"replicas":[4]},{"topic":"cluster-switch-topic","partition":9,"replicas":[4]},{"topic":"cluster-switch-topic","partition":1,"replicas":[4]},{"topic":"cluster-switch-topic","partition":11,"replicas":[4]},{"topic":"cluster-switch-topic","partition":7,"replicas":[4]},{"topic":"cluster-switch-topic","partition":2,"replicas":[5]},{"topic":"cluster-switch-topic","partition":0,"replicas":[5]},{"topic":"cluster-switch-topic","partition":6,"replicas":[5]},{"topic":"cluster-switch-topic","partition":8,"replicas":[5]}]}

3、执行：

执行后会生成一个json格式文件expand-cluster-reassignment.json

4、查询执行状态：

正常执行后会返回当前数据迁移的不用partion的，信息状态类似下面

这样做不会影响原来集群上的topic业务

2.topic修改(replicats-factor)副本个数

假如初始时push-token-topic为一个副本，为了提高可用性，需要改为2副本模式。

脚本replicas-update-push-token-topic.json文件内容如下:

{

"partitions":

[

{

"topic": "log.mobile_nginx",

"partition": 0,

"replicas": [101,102,104]

},

{

"topic": "log.mobile_nginx",

"partition": 1,

"replicas": [102,103,106]

}

],

"version":1

}

2、执行：

执行后会列出当前的partition和修改后的patition

3、verify

如下：

Status of partition reassignment:

Reassignment of partition [log.mobile_nginx,0] completed successfully

Reassignment of partition [log.mobile_nginx,1] completed successfully

3.自定义分区和迁移

1、The first step is to hand craft the custom reassignment plan in a json file-

> cat custom-reassignment.json

{"version":1,"partitions":[{"topic":"foo1","partition":0,"replicas":[5,6]},{"topic":"foo2","partition":1,"replicas":[2,3]}]}

2、Then, use the json file with the --execute option to start the reassignment process-

> bin/kafka-reassign-partitions.sh --zookeeper localhost:2181 --reassignment-json-file custom-reassignment.json --execute

Current partition replica assignment

{"version":1,

 "partitions":[{"topic":"foo1","partition":0,"replicas":[1,2]},

               {"topic":"foo2","partition":1,"replicas":[3,4]}]

}

Save this to use as the --reassignment-json-file option during rollback

Successfully started reassignment of partitions

{"version":1,

 "partitions":[{"topic":"foo1","partition":0,"replicas":[5,6]},

               {"topic":"foo2","partition":1,"replicas":[2,3]}]

}

3、The --verify option can be used with the tool to check the status of the partition reassignment. Note that the same expand-cluster-reassignment.json (used with the --execute option) should be used with the --verify option

bin/kafka-reassign-partitions.sh --zookeeper localhost:2181 --reassignment-json-file custom-reassignment.json --verify

Status of partition reassignment:

Reassignment of partition [foo1,0] completed successfully

Reassignment of partition [foo2,1] completed successfully

4.topic的分区扩容用法

a.先扩容分区数量，脚本如下:

例如:push-token-topic初始分区数量为12，目前到增加到15个

root@localhost:$ ./bin/kafka-topics.sh --zookeeper 192.168.2.225:2183 --alter --partitions 15 --topic   push-token-topic

b.设置topic分区副本

root@localhost:$ ./bin/kafka-reassign-partitions.sh --zookeeper  192.168.2.225:2183

--reassignment-json-file partitions-extension-push-token-topic.json  --execute

脚本partitions-extension-push-token-topic.json文件内容如下:

{

"partitions":

[

{

"topic": "push-token-topic",

"partition": 12,

"replicas": [101,102]

},

{

"topic": "push-token-topic",

"partition": 13,

"replicas": [103,104]

},

{

"topic": "push-token-topic",

"partition": 14,

"replicas": [105,106]

}

],

"version":1

}