3）开始看README.md文档，特意看了下kafka的兼容性 看来logstas-input-kafka5.0.5和logstash-output-kafka5.0.4只能用kafka0.10了。如果你想用Kafka0.9还想用Logstash5.0,你的
logstash-input-kafka和logstash-output-kafka只能降级版本到4.0.0了，这里都说他是中间过渡版本了，所以还是随大流吧。
## Kafka Compatibility
Here's a table that describes the compatibility matrix for Kafka Broker support. Please remember that it is good advice to upgrade brokers before consumers/producers
since brokers target backwards compatibility. The 0.9 broker will work with both the 0.8 consumer and 0.9 consumer APIs but not the other way around.
| Kafka Broker Version | Logstash Version | Input Plugin | Output Plugin | Why? |
|:---------------:|:------------------:|:--------------:|:---------------:|:------|
| 0.8 | 2.0 - 2.x | < 3.0.0 | <3.0.0 | Legacy, 0.8 is still popular |
| 0.9 | 2.0 - 2.3.x | 3.0.0 | 3.0.0 | Intermediate release before 0.10 that works with old Ruby Event API `[]` |
| 0.9 | 2.4, 5.0 | 4.0.0 | 4.0.0 | Intermediate release before 0.10 with new get/set API |
| 0.10 | 2.4, 5.0 | 5.0.0 | 5.0.0 | Track latest Kafka release. Not compatible with 0.9 broker |
4）现在看来只能升级kafka版本了。最后我看了下jar-dependencies发现了kafka-clients-0.10.0.1.jar
ls /usr/share/logstash/vendor/bundle/jruby/1.9/gems/logstash-input-kafka-5.0.5/vendor/jar-dependencies/runtime-jars/
kafka-clients-0.10.0.1.jar log4j-1.2.17.jar lz4-1.3.0.jar slf4j-api-1.7.21.jar slf4j-log4j12-1.7.21.jar snappy-java-1.1.2.6.jar
5）还有一个文件没有看，怀着好奇心我看了一眼，发现之前都白费力气了，这里才是最有参考价值的的主参考文档啊，是捷径啊，隐藏的够深的，差点错过了，汗！
/usr/share/logstash/vendor/bundle/jruby/1.9/gems/logstash-input-kafka-5.0.5/lib/logstash/inputs/kafka.rb
kafka.rb部分文档如下：
# This input will read events from a Kafka topic. It uses the the newly designed
# 0.10 version of consumer API provided by Kafka to read messages from the broker.
#
# Here's a compatibility matrix that shows the Kafka client versions that are compatible with each combination
# of Logstash and the Kafka input plugin:
#
# [options="header"]
# |==========================================================
# |Kafka Client Version |Logstash Version |Plugin Version |Security Features |Why?
# |0.8 |2.0.0 - 2.x.x |<3.0.0 | |Legacy, 0.8 is still popular
# |0.9 |2.0.0 - 2.3.x | 3.x.x |Basic Auth, SSL |Works with the old Ruby Event API (`event['product']['price'] = 10`)
# |0.9 |2.4.0 - 5.0.x | 4.x.x |Basic Auth, SSL |Works with the new getter/setter APIs (`event.set('[product][price]', 10)`)
# |0.10 |2.4.0 - 5.0.x | 5.x.x |Basic Auth, SSL |Not compatible with the 0.9 broker
# |==========================================================
#
# NOTE: We recommended that you use matching Kafka client and broker versions. During upgrades, you should
# upgrade brokers before clients because brokers target backwards compatibility. For example, the 0.9 broker
# is compatible with both the 0.8 consumer and 0.9 consumer APIs, but not the other way around.
6）升级kafka_2.10-0.8.2.2.tgz为kafka_2.11-0.10.0.1.tgz （我看kafka-clients-0.10.0.1.jar，所以没有用最新的kafka_2.11-0.10.1.0.tgz）
大概步骤
关闭老kafka
/usr/local/kafka/bin/kafka-server-stop.sh /usr/local/kafka/config/server.properties
备份老配置文件
server.properties和zookeeper.properties
删除kafka
rm -rf /usr/local/kafka/
rm -rf /data/kafkalogs/*
安装配置新kafka
wget
tar zxvf kafka_2.11-0.10.0.1.tgz -C /usr/local/
ln -s /usr/local/kafka_2.11-0.10.0.1 /usr/local/kafka
diff了下server.properties和zookeeper.properties变动不大可以直接使用
启动新kafka
/usr/local/kafka/bin/kafka-server-start.sh /usr/local/kafka/config/server.properties &
7)注意几个关键配置需要修改
config :bootstrap_servers, :validate => :string, :default => "localhost:9092"
config :group_id, :validate => :string, :default => "logstash"
config :topics, :validate => :array, :default => ["logstash"]
config :consumer_threads, :validate => :number, :default => 1
除了上面的几个关键配置外，kafka的topic分片信息需要重新create一份，否则KafkaMonitor监控不出Active Topic Consumer图形，但实际是在工作中。