Flume官方文档上写的配置写法适用于es版本<2.0
我用的是flume1.6和ES2.2版本，会报错

解决方案：

Flume-NG Sink for Elasticsarch >= 2.0：
https://github.com/lucidfrontier45/ElasticsearchSink2

Requirements：
Flume-NG >= 1.6
Elasticsearch >= 2.0

JAR Build：
Build standard jar by the following command

$ ./gradlew build

Build fat jar which contains elasticsearch dependencies

$ ./gradlew assembly

Jar will be generated in build/libs

把jar包放到flume的lib下，然后
remove guava-.jar and jackson-core-.jar in flume’s default libs dir. They are outdated and newer version are included in Elasticsearch.

把ES目录lib下的jar都放到flume的lib下

然后就可以开始写配置文件了

新建一个flume的.properties文件

vim flume-conf-kafka2es.properties

# ------------------- 定义数据流----------------------
# source的名字
flume2es_agent.sources = source_from_kafka  
# channels的名字，建议按照type来命名
flume2es_agent.channels = mem_channel  
# sink的名字，建议按照目标来命名
flume2es_agent.sinks = es_sink  

#auto.commit.enable = true  

#-------- kafkaSource相关配置-----------------
# 定义消息源类型
# For each one of the sources, the type is defined  
flume2es_agent.sources.source_from_kafka.type = org.apache.flume.source.kafka.KafkaSource  
flume2es_agent.sources.source_from_kafka.channels = mem_channel  
flume2es_agent.sources.source_from_kafka.batchSize = 5000  

# 定义kafka所在的地址
flume2es_agent.sources.source_from_kafka.kafka.bootstrap.servers = 192.168.2.xx:9092,192.168.2.xx:9092

# 配置消费的kafka topic
#flume2es_agent.sources.source_from_kafka.topic = itil_topic_4097  
flume2es_agent.sources.source_from_kafka.kafka.topics = mtopic

# 配置消费的kafka groupid
#flume2es_agent.sources.source_from_kafka.groupId = flume4097  
flume2es_agent.sources.source_from_kafka.kafka.consumer.group.id = flumetest

#---------ES Sink 相关配置------------------
# The channel can be defined as follows.  
#flume2es_agent.sinks.es_sink.type = org.apache.flume.sink.elasticsearch.ElasticSearchSink 
flume2es_agent.sinks.es_sink.type = com.frontier45.flume.sink.elasticsearch2.ElasticSearchSink
# 指定sink需要使用的channel的名字,注意这里是channel
#Specify the channel the sink should use  
flume2es_agent.sinks.es_sink.channel = mem_channel  
#flume2es_agent.sinks.es_sink.filePrefix = %{host}  
flume2es_agent.sinks.es_sink.hostNames = cdh1,cdh2,cdh3,cdh4,cdh5,cdh6  

flume2es_agent.sinks.es_sink.clusterName = elasticsearch

flume2es_agent.sinks.es_sink.indexName = items
flume2es_agent.sinks.es_sink.indexTypeitems = item

flume2es_agent.sinks.es_sink.serializer = com.frontier45.flume.sink.elasticsearch2.ElasticSearchDynamicSerializer
flume2es_agent.sinks.es_sink.indexNameBuilder = com.frontier45.flume.sink.elasticsearch2.TimeBasedIndexNameBuilder

#File size to trigger roll, in bytes (0: never roll based on file size)
flume2es_agent.sinks.es_sink.batchSize = 500  


#------- memoryChannel相关配置-------------------------
# channel类型
# Each channel's type is defined.  
flume2es_agent.channels.mem_channel.type = memory  
# Other config values specific to each type of channel(sink or source)  
# can be defined as well  
# channel存储的事件容量
# In this case, it specifies the capacity of the memory channel  
flume2es_agent.channels.mem_channel.capacity = 100000  
# 事务容量
flume2es_agent.channels.mem_channel.transactionCapacity = 10000  

运行：

>flume-ng agent -n flume2HDFS_agent -f flume-conf-kafka2es.properties

控制台打开一个producer发送消息试一下吧：

>kafka-console-producer --broker-list cdh5:9092 --topic mtopic