Flume开发 -- 故障转移和负载均衡
一、需求
使用 Flume1 监控一个端口，其 sink 组中的 sink 分别对接 Flume2 和 Flume3，采用
FailoverSinkProcessor，实现故障转移功能。
二、流程分析
三、实现步骤
3.1 准备工作
在 /opt/module/flume/job 目录下创建 group2 文件夹
[test@hadoop151 job]$ mkdir group2
3.2 创建 flume-netcat-flume.conf
配置一个 netcat source 和一个 channel、一个 sink group(2 个 sink)，分别输送给 flume-flume-console1 和 flume-flume-console2。
1、编辑配置文件
[test@hadoop151 group2]$ vim flume-netcat-flume.conf
2、添加如下内容
# Name the components on this agent
a1.sources = r1
a1.channels = c1
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
# Describe the sinkgroups
a1.sinkgroups.g1.processor.type = failover
a1.sinkgroups.g1.processor.priority.k1 = 5
a1.sinkgroups.g1.processor.priority.k2 = 10
a1.sinkgroups.g1.processor.maxpenalty = 10000
# Describe the sink
a1.sinks.k1.type = avro
a1.sinks.k1.hostname = hadoop151
a1.sinks.k1.port = 4141
a1.sinks.k2.type = avro
a1.sinks.k2.hostname = hadoop151
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
3.3 创建 flume-flume-console1.conf
配置上级 Flume 输出的 Source，输出是到本地控制台。
1、编辑配置文件
[test@hadoop151 group2]$ vim flume-flume-console1.conf
2、添加如下内容
# 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 = hadoop151
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
3.4 创建 flume-flume-console2.conf
配置上级 Flume 输出的 Source，输出是本地控制台。
1、编辑配置文件
[test@hadoop151 group2]$ vim flume-flume-console2.conf
2、添加如下内容
# 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 = hadoop151
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
3.5 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。
[test@hadoop151 flume]$ bin/flume-ng agent --conf conf/ --name a3 --conf-file job/group2/flume-flume-console2.conf -Dflume.root.logger=INFO,console
[test@hadoop151 flume]$ bin/flume-ng agent --conf conf/ --name a2 --conf-file job/group2/flume-flume-console1.conf -Dflume.root.logger=INFO,console
[test@hadoop151 flume]$ bin/flume-ng agent --conf conf/ --name a1 --conf-file job/group2/flume-netcat-flume.conf
3.6 使用 netcat 工具向本机的 44444 端口发送内容
3.7 查看 Flume2 和 Flume3 的控制台打印日志
我们可以发现，Flume3 打印，而 Flume2 不打印，因为这里设置的是故障转移的 Flume，只有工作的服务器 down 掉，才会使用下一台。
Flume3：
Flume2：
3.8 将 Flume3 kill，观察 Flume2 的控制台打印情况
Flume3：
Flume2：
注：使用 jps -ml 查看 Flume 进程
四、负载均衡的配置
配置负载均衡只需要把 flume-netcat-flume.conf 文件中的参数：
# Describe the sinkgroups
a1.sinkgroups.g1.processor.type = failover
a1.sinkgroups.g1.processor.priority.k1 = 5
a1.sinkgroups.g1.processor.priority.k2 = 10
a1.sinkgroups.g1.processor.maxpenalty = 10000
修改为：
a1.sinkgroups.g1.processor.type = load_balance
a1.sinkgroups.g1.processor.backoff = true
a1.sinkgroups.g1.processor.selector = random
这样就可以实现两个 Flume 都可以随机接收到数据。