# 创建Kafka Topic时报错"replication factor larger than available brokers"
#### 问题背景与现象
在使用Kafka客户端命令创建Topic时，发现Topic无法被创建。
```
kafka-topics.sh --create  --replication-factor 2 --partitions 2 --topic test --zookeeper 192.168.234.231:2181
```
提示错误replication factor larger than available brokers。
具体如下：
```
Error while executing topic command : replication factor: 2 larger than available brokers: 0
[2017-09-17 16:44:12,396] ERROR kafka.admin.AdminOperationException: replication factor: 2 larger than available brokers: 0
at kafka.admin.AdminUtils$.assignReplicasToBrokers(AdminUtils.scala:117)
at kafka.admin.AdminUtils$.createTopic(AdminUtils.scala:403)
at kafka.admin.TopicCommand$.createTopic(TopicCommand.scala:110)
at kafka.admin.TopicCommand$.main(TopicCommand.scala:61)
at kafka.admin.TopicCommand.main(TopicCommand.scala)
 (kafka.admin.TopicCommand$)
```
#### 可能原因
- Kafka服务处于停止状态。
- Kafka服务当前可用Broker小于设置的replication-factor。
- 客户端命令中ZooKeeper地址参数配置错误。
 
#### 原因分析
1. 使用客户端命令，打印replication factor larger than available brokers异常。
   ```
   Error while executing topic command : replication factor: 2 larger than available brokers: 0
   [2017-09-17 16:44:12,396] ERROR kafka.admin.AdminOperationException: replication factor: 2 larger than available brokers: 0
   at kafka.admin.AdminUtils$.assignReplicasToBrokers(AdminUtils.scala:117)
   at kafka.admin.AdminUtils$.createTopic(AdminUtils.scala:403)
   at kafka.admin.TopicCommand$.createTopic(TopicCommand.scala:110)
   at kafka.admin.TopicCommand$.main(TopicCommand.scala:61)
   at kafka.admin.TopicCommand.main(TopicCommand.scala)
    (kafka.admin.TopicCommand$)
   ```
   
2. 通过Manager参看Kafka服务是否处于正常状态，当前可用Broker是否小于设置的replication-factor。
3. 检查客户端命令中ZooKeeper地址是否正确，访问ZooKeeper上所存放的Kafka信息，其路径（Znode）应该加上/kafka，发现配置中缺少/kafka。
   ```
   [root@10-10-144-2 client]# 
   kafka-topics.sh --create  --replication-factor 2 --partitions 2 --topic test --zookeeper 192.168.234.231:2181
   ```
   
 
#### 解决办法
1. 保证Kafka服务处于正常状态，且可用Broker不小于设置的replication-factor。
2. 创建命令中ZooKeeper地址信息需要添加/kafka。 
   ```
   [root@10-10-144-2 client]# 
   kafka-topics.sh --create  --replication-factor 1 --partitions 2 --topic test --zookeeper 192.168.234.231:2181/kafka
   ```