大数据技术之Flume（扇出）

扇出：一个Flume向几个Flume输出。
目标：使用flume1监控文件变动，flume1将变动内容传递给flume-2，flume-2负责存储到HDFS。同时flume1将变动内容传递给flume-3，flume-3负责输出到local

分步实现：
1：创建flume1.conf，用于监控某文件的变动，同时产生两个channel和两个sink分别输送给flume2和flume3：

#1.agent
source->channel对应关系1/n sink->channel对应关系1/1
a1.sources = r1a1.sinks = k1 k2
a1.channels = c1 c2
#将数据流复制给多个channel
a1.sources.r1.selector.type = replicating

#2.source
a1.sources.r1.type = exec
a1.sources.r1.command = tail -F /opt/plus
a1.sources.r1.shell = /bin/bash -c

#3.sink1
a1.sinks.k1.type = avro
a1.sinks.k1.hostname = bigdata112
a1.sinks.k1.port = 4141
#sink2
a1.sinks.k2.type = avro
a1.sinks.k2.hostname = bigdata113
a1.sinks.k2.port = 4141

#4.channel—1
a1.channels.c1.type = memory
a1.channels.c1.capacity = 1000
a1.channels.c1.transactionCapacity = 100
#4.channel—2
a1.channels.c2.type = memory
a1.channels.c2.capacity = 1000
a1.channels.c2.transactionCapacity = 100
#Bind the source and sink to the channel
a1.sources.r1.channels = c1 c2
a1.sinks.k1.channel = c1
a1.sinks.k2.channel = c2

2：创建flume-2.conf，用于接收flume1的event，同时产生1个channel和1个sink，将数据输送给hdfs：
#1 agent
a2.sources = r1
a2.sinks = k1
a2.channels = c1

#2 source
a2.sources.r1.type = avro
a2.sources.r1.bind = bigdata112
a2.sources.r1.port = 4141

#3 sink
a2.sinks.k1.type = hdfs
a2.sinks.k1.hdfs.path = hdfs://bigdata111:9000/flume2/%H
#上传文件的前缀
a2.sinks.k1.hdfs.filePrefix = flume2
-#是否按照时间滚动文件夹
a2.sinks.k1.hdfs.round = true
#多少时间单位创建一个新的文件夹
a2.sinks.k1.hdfs.roundValue = 1
#重新定义时间单位
a2.sinks.k1.hdfs.roundUnit = hour
#是否使用本地时间戳
a2.sinks.k1.hdfs.useLocalTimeStamp = true
#积攒多少个Event才flush到HDFS一次
a2.sinks.k1.hdfs.batchSize = 100
#设置文件类型，可支持压缩
a2.sinks.k1.hdfs.fileType = DataStream
#多久生成一个新的文件
a2.sinks.k1.hdfs.rollInterval = 600
#设置每个文件的滚动大小大概是128M
a2.sinks.k1.hdfs.rollSize = 134217700
#文件的滚动与Event数量无关
a2.sinks.k1.hdfs.rollCount = 0
#最小副本数
a2.sinks.k1.hdfs.minBlockReplicas = 1

#4 channel
a2.channels.c1.type = memory
a2.channels.c1.capacity = 1000
a2.channels.c1.transactionCapacity = 100
#5 Bind
a2.sources.r1.channels = c1
a2.sinks.k1.channel = c1

3：创建flume-3.conf，用于接收flume1的event，同时产生1个channel和1个sink，将数据输送给本地目录：
#1 agent
a3.sources = r1
a3.sinks = k1
a3.channels = c1

#2 source
a3.sources.r1.type = avro
a3.sources.r1.bind = bigdata113
a3.sources.r1.port = 4141

#3 sink
a3.sinks.k1.type = file_roll
#备注：此处的文件夹需要先创建好
a3.sinks.k1.sink.directory = /opt/flume3

#4 channel
a3.channels.c1.type = memory
a3.channels.c1.capacity = 1000
a3.channels.c1.transactionCapacity = 100

#5 Bind
a3.sources.r1.channels = c1
a3.sinks.k1.channel = c1
尖叫提示：输出的本地目录必须是已经存在的目录，如果该目录不存在，并不会创建新的目录。

4：执行测试：分别开启对应flume-job（依次启动flume1，flume-2，flume-3），同时产生文件变动并观察结果：
$ bin/flume-ng agent --conf conf/ --name a1 --conf-file jobconf/flume1.conf
$ bin/flume-ng agent --conf conf/ --name a2 --conf-file jobconf/flume2.conf
$ bin/flume-ng agent --conf conf/ --name a3 --conf-file jobconf/flume3.conf