2.2. 采集案例

2.2.4. 采集文件到HDFS

​需求​

比如业务系统使用log4j生成的日志，日志内容不断增加，需要把追加到日志文件中的数据实时采集到 hdfs

​分析​

根据需求，首先定义以下3大要素

• • 
    
• 采集源，即source——监控文件内容更新 : exec ‘tail -F file’
• 下沉目标，即sink——HDFS文件系统 : hdfs sink
• Source和sink之间的传递通道——channel，可用file channel 也可以用 内存channel
  • 
    

Step 1: 定义 Flume 配置文件

cd /export/servers/apache-flume-1.8.0-bin/conf 
vim tail-file.conf

agent1.sources = source1 
agent1.sinks = sink1 
agent1.channels = channel1 
# Describe/configure tail -F source1 
agent1.sources.source1.type = exec 
agent1.sources.source1.command = tail -F /export/servers/taillogs/access_log 
agent1.sources.source1.channels = channel1 
# Describe sink1 
agent1.sinks.sink1.type = hdfs 
#a1.sinks.k1.channel = c1 
agent1.sinks.sink1.hdfs.path = hdfs://node01:8020/weblog/flume-collection/%y-%m-%d/%H-% 
agent1.sinks.sink1.hdfs.filePrefix = access_log 
agent1.sinks.sink1.hdfs.maxOpenFiles = 5000 
agent1.sinks.sink1.hdfs.batchSize= 100 
agent1.sinks.sink1.hdfs.fileType = DataStream 
agent1.sinks.sink1.hdfs.writeFormat =Text 
agent1.sinks.sink1.hdfs.round = true 
agent1.sinks.sink1.hdfs.roundValue = 10 
agent1.sinks.sink1.hdfs.roundUnit = minute 
agent1.sinks.sink1.hdfs.useLocalTimeStamp = true 
# Use a channel which buffers events in memory 
agent1.channels.channel1.type = memory 
agent1.channels.channel1.keep-alive = 120 
agent1.channels.channel1.capacity = 500000 
agent1.channels.channel1.transactionCapacity = 600 
# Bind the source and sink to the channel 
agent1.sources.source1.channels = channel1 
agent1.sinks.sink1.channel = channel1

Step 2: 启动 Flume

cd /export/servers/apache-flume-1.6.0-cdh5.14.0-bin bin/flume-ng agent -c conf -f conf/tail-file.conf -n agent1

Step 3: 开发 Shell 脚本定时追加文件内容

mkdir -p /export/servers/shells/ 
cd /export/servers/shells/ 
vim tail-file.sh

#!/bin/bash 
while true dodate >> /export/servers/taillogs/access_log; sleep 0.5; done

Step 4: 启动脚本

# 创建文件夹 
mkdir -p /export/servers/taillogs 
# 启动脚本 
sh /export/servers/shells/tail-file.sh