关于failover网上也有很多例子，但是看到的有多重做法，个人觉得，本着职责单一的原则

1、一台机子运行一个flume agent

2、一个agent 的下游sink指向一个flume agent，不要一个flume agent配置多个端口【影响性能】

3、分机子配置，可以避免一台机子司机，另一个仍可以使用，否则陪在一台机子上通过端口区分，一旦死机，全盘崩溃

下面看具体实例：

首先是flumet agent client的配置

priority越高，优先级越高，会优先使用该sink

# Name the components on this agent
a1.sources = r1
a1.sinks = k1 k2
a1.channels = c1
 
# Describe/configure the source
a1.sources.r1.type = exec
a1.sources.r1.channels=c1
a1.sources.r1.command=tail -F /root/dev/biz/logs/bizlogic.log

#define sinkgroups
a1.sinkgroups=g1
a1.sinkgroups.g1.sinks=k1 k2
a1.sinkgroups.g1.processor.type=failover
a1.sinkgroups.g1.processor.priority.k1=10
a1.sinkgroups.g1.processor.priority.k2=5
a1.sinkgroups.g1.processor.maxpenalty=10000

#define the sink 1
a1.sinks.k1.type=avro
a1.sinks.k1.hostname=192.168.11.179
a1.sinks.k1.port=9876

#define the sink 2
a1.sinks.k2.type=avro
a1.sinks.k2.hostname=192.168.11.178
a1.sinks.k2.port=9876


# Use a channel which buffers events in memory
a1.channels.c1.type = memory
a1.channels.c1.capacity = 1000
a1.channels.c1.transactionCapacity = 100

# Bind the source and sink to the channel
a1.sources.r1.channels = c1
a1.sinks.k1.channel = c1
a1.sinks.k2.channel=c1

再来看flume agent server的配置，即179,178的配置，看一个即可

# Name the components on this agent
a1.sources = r1
a1.sinks = k1
a1.channels = c1
 
# Describe/configure the source
a1.sources.r1.type=avro
#any address to listen
a1.sources.r1.bind=0.0.0.0
a1.sources.r1.port=9876
a1.sources.r1.channels=c1

# Describe the sink
a1.sinks.k1.type = file_roll
a1.sinks.k1.sink.directory=/root/dev/flumeout/file
a1.sinks.k1.sink.rollInterval=3600


# Use a channel which buffers events in memory
a1.channels.c1.type = memory
a1.channels.c1.capacity = 1000
a1.channels.c1.transactionCapacity = 100

# Bind the source and sink to the channel
a1.sources.r1.channels = c1
a1.sinks.k1.channel = c1

可以看出flume agent client和server之间是通过avro来传输数据的，avro是flume内置的协议，非常方便，可以将flume整个串起来

下面先启动flume agent server，再启动flume agent client

测试如下：

for i in {1..100};
do echo "exec test tail -f $i  on terminator 176" >> bizlogic.log;
echo $i;
sleep 0.1;
done

起初启动的时候，178和179都会产生此文件，但是当你开始产生文件内容的时候，也还有179才会写入文件内容了

至此，完整的flume failover 机制就走通了，共勉！

【Flume】flume 容错环境的搭建 failover