排查logstash2.4升级到5.0版本后kafka不兼容问题
参考文档：
/usr/share/logstash/vendor/bundle/jruby/1.9/gems/logstash-input-kafka-5.0.5/CHANGELOG.md
/usr/share/logstash/vendor/bundle/jruby/1.9/gems/logstash-input-kafka-5.0.5/DEVELOPER.md
/usr/share/logstash/vendor/bundle/jruby/1.9/gems/logstash-input-kafka-5.0.5/README.md.md
/usr/share/logstash/vendor/bundle/jruby/1.9/gems/logstash-input-kafka-5.0.5/lib/logstash/inputs/kafka.rb
/usr/share/logstash/vendor/bundle/jruby/1.9/gems/logstash-output-kafka-5.0.4/lib/logstash/outputs/kafka.rb
缘由：
之前对ELKB环境从2.4版本升级到最新的5.0稳定版本，主要升级步骤可以参考http://blog.chinaunix.net/uid-25057421-id-5754668.html，后来发现kafka集群运行报错，现在把排查过程记录如下，仅供参考
之前环境：
logstash2.4
logstash-input-kafka-2.0.9
logstash-output-kafka-2.0.5
kafka_2.10-0.8.2.2.tgz
升级后环境：
logstash5.0
logstash-input-kafka-2.0.9
logstash-output-kafka-2.0.5
报错信息：
[2016-11-16T14:35:44,739][ERROR][logstash.inputs.kafka ] Unknown setting 'zk_connect' for kafka
[2016-11-16T14:35:44,741][ERROR][logstash.inputs.kafka ] Unknown setting 'topic_id' for kafka
[2016-11-16T14:35:44,741][ERROR][logstash.inputs.kafka ] Unknown setting 'reset_beginning' for kafka
实施步骤：
1，根据错误查看程序哪里报错
grep "Unknown setting" /usr/share/logstash/ -R
/usr/share/logstash/logstash-core/lib/logstash/config/mixin.rb: self.logger.error("Unknown setting '#{name}' for #{@plugin_name}")
2，查看程序相关代码，发现需要查看plugins的config定义文件等
def validate_check_invalid_parameter_names(params)
invalid_params = params.keys
# Filter out parameters that match regexp keys.
# These are defined in plugins like this:
# config /foo.*/ => ...
@config.each_key do |config_key|
if config_key.is_a?(Regexp)
invalid_params.reject! { |k| k =~ config_key }
elsif config_key.is_a?(String)
invalid_params.reject! { |k| k == config_key }
end
end
if invalid_params.size > 0
invalid_params.each do |name|
self.logger.error("Unknown setting '#{name}' for #{@plugin_name}")
end
return false
end # if invalid_params.size > 0
return true
end # def validate_check_invalid_parameter_names
3，进入插件总目录查看具体信息
cd /usr/share/logstash/vendor/bundle/jruby/1.9/gems/logstash-input-kafka-5.0.5
发现重点查看如下文件
grep config ./* -R |awk '{print $1}' |uniq
./CHANGELOG.md:
./DEVELOPER.md:See
./lib/logstash/inputs/kafka.rb:#
./lib/logstash/inputs/kafka.rb:
./README.md:-
Binary
1）首先看CHANGELOG.md，就有发现logstash-input-3.0.0.beta1开始就不在向后兼容，且剔除了jruby-kafka，注意这里有个坑2）会讲到，4.0.0版本说开始支持kafka 0.9，5.0.0又说开始
支持0.10切不向后兼容，这破坏性更新也是够了。看来问题找到了我的kafka版本是kafka_2.10-0.8.2.2.tgz，kafka版本不兼容导致的。
CHANGELOG.md部分文档如下：
## 5.0.4
- Update to Kafka version 0.10.0.1 for bug fixes
## 5.0.0
- Support for Kafka 0.10 which is not backward compatible with 0.9 broker.
## 4.0.0
- Republish all the gems under jruby.
- Update the plugin to the version 2.0 of the plugin api, this change is required for Logstash 5.0 compatibility. See
- Support for Kafka 0.9 for LS 5.x
## 3.0.0.beta1
- Refactor to use new Java based consumer, bypassing jruby-kafka
- Breaking: Change configuration to match Kafka's configuration. This version is not backward compatible
2）之前我看DEVELOPER.md文档时,看配置语法都正确，还以为是却少依赖关系jruby-kafka library呢，这个再logstash2.x是在用的(另外对比logstash5.x发现5版本少了不少插件。另外
kafka版本写的是0.8.1.1，看来这个DEVELOPER.md没有及时更新（与后面kafka.rb文件不一致），谁要是看到了麻烦及时更新啊，虽是小问题但是也可能误导我等屁民。当然也有可能是我没
有全面看文档导致的。
DEVELOPER.md文档结尾如下：
Dependencies
====================
* Apache Kafka version 0.8.1.1
* jruby-kafka library
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。
