逻辑架构

单Source、Channel多Sink(负载均衡)如图7-3所示。

1）案例需求：使用Flume-1监控文件变动，Flume-1将变动内容传递给Flume-2，Flume-2负责存储到HDFS。同时Flume-1将变动内容传递给Flume-3，Flume-3也负责存储到HDFS
2）需求分析：

3）实现步骤：
在/opt/module/flume/job目录下创建group2文件夹

[root@note01 job]# mkdir group2
[root@note01 job]# cd group2/

1．创建flume-netcat-flume.conf

配置1个接收日志文件的source和1个channel、两个sink，分别输送给flume-flume-console1和flume-flume-console2。

vim flume-netcat-flume.conf

# 命名组件
a1.sources = r1
a1.channels = c1
# 配置sink组
a1.sinkgroups = g1
a1.sinks = k1 k2

# Describe/configure the source
a1.sources.r1.type = netcat
a1.sources.r1.bind = localhost
a1.sources.r1.port = 44444

# 配置选择器
a1.sinkgroups.g1.processor.type = load_balance
a1.sinkgroups.g1.processor.backoff = true
a1.sinkgroups.g1.processor.selector = round_robin
a1.sinkgroups.g1.processor.selector.maxTimeOut=10000

# Describe the sink
a1.sinks.k1.type = avro
a1.sinks.k1.hostname = note01
a1.sinks.k1.port = 4141

a1.sinks.k2.type = avro
a1.sinks.k2.hostname = note01
a1.sinks.k2.port = 4142


# Describe the channel
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.sinkgroups.g1.sinks = k1 k2
a1.sinks.k1.channel = c1
a1.sinks.k2.channel = c1

注： Avro是由Hadoop创始人Doug Cutting创建的一种语言无关的数据序列化和RPC框架。
注： RPC（Remote Procedure Call）—远程过程调用，它是一种通过网络从远程计算机程序上请求服务，而不需要了解底层网络技术的协议。

2. 创建flume-flume-console1.conf

配置上级Flume输出的Source，输出是到本地控制台。
创建配置文件并打开

 vim flume-flume-console1.conf

# Name the components on this agent
a2.sources = r1
a2.sinks = k1
a2.channels = c1

# Describe/configure the source
a2.sources.r1.type = avro
a2.sources.r1.bind = note01
a2.sources.r1.port = 4141

# Describe the sink
a2.sinks.k1.type = logger

# Describe the channel
a2.channels.c1.type = memory
a2.channels.c1.capacity = 1000
a2.channels.c1.transactionCapacity = 100

# Bind the source and sink to the channel
a2.sources.r1.channels = c1
a2.sinks.k1.channel = c1
                            

3．创建flume-flume-console2.conf

vim flume-flume-console2.conf

# Name the components on this agent
a3.sources = r1
a3.sinks = k1
a3.channels = c2

# Describe/configure the source
a3.sources.r1.type = avro
a3.sources.r1.bind = note01
a3.sources.r1.port = 4142

# Describe the sink
a3.sinks.k1.type = logger

# Describe the channel
a3.channels.c2.type = memory
a3.channels.c2.capacity = 1000
a3.channels.c2.transactionCapacity = 100

# Bind the source and sink to the channel
a3.sources.r1.channels = c2
a3.sinks.k1.channel = c2

执行配置文件

分别开启对应配置文件：flume-flume-console2，flume-flume-console1，flume-netcat-flume
启动主

 bin/flume-ng agent --conf conf/ --name a1 --conf-file job/group2/flume-netcat-flume.conf

启动两个负载

bin/flume-ng agent --conf conf/ --name a2 --conf-file job/group2/flume-flume-console1.conf -Dflume.root.logger=INFO,console

 bin/flume-ng agent --conf conf/ --name a3 --conf-file job/group2/flume-flume-console2.conf -Dflume.root.logger=INFO,console

使用netcat工具向本机的44444端口发送内容

nc localhost 44444

可以发现1,2对数据进行负载均衡