Flume安装
系统要求：
需安装JDK 1.7及以上版本
1、 下载二进制包
下载页面：http://flume.apache.org/download.html
1.7.0下载地址：http://www.apache.org/dyn/closer.lua/flume/1.7.0/apache-flume-1.7.0-bin.tar.gz
2、解压
$ cp ~/Downloads/apache-flume-1.7.0-bin.tar.gz ~
$ cd
$ tar -zxvf apache-flume-1.7.0-bin.tar.gz
$ cd apache-flume-1.7.0-bin
3、创建flume-env.sh文件
$ cp conf/flume-env.sh.template conf/flume-env.sh
简单实例－传输指定文件
场景：两台机器，一台为client，一台为agent，在client上将指定文件传输到agent机器上。
1、创建配置文件
根据flume自身提供的模板，创建flume.conf配置文件。
$ cp conf/flume-conf.properties.template conf/flume.conf
编辑文件flume.conf：
$ vi conf/flume.conf
在文件末尾加入以下配置：
# Define a memory channel called ch1 on agent1
agent1.channels.ch1.type = memory
# Define an Avro source called avro-source1 on agent1 and tell it
# to bind to 0.0.0.0:41414. Connect it to channel ch1.
agent1.sources.avro-source1.channels = ch1
agent1.sources.avro-source1.type = avro
agent1.sources.avro-source1.bind = 0.0.0.0
agent1.sources.avro-source1.port = 41414
# Define a logger sink that simply logs all events it receives
# and connect it to the other end of the same channel.
agent1.sinks.log-sink1.channel = ch1
agent1.sinks.log-sink1.type = logger
# Finally, now that we've defined all of our components, tell
# agent1 which ones we want to activate.
agent1.channels = ch1
agent1.sources = avro-source1
agent1.sinks = log-sink1
保存，并且退出：
2、启动flume server
在作为agent的机器上执行以下：
bin/flume-ng agent --conf ./conf/ -f conf/flume.conf -Dflume.root.logger=DEBUG,console -n agent1
3、在新的窗口开启client
在作为client的机器上执行以下：
（由于当前环境是在单机上模拟两台机器，所以，直接在新的终端中输入以下命令）
$ bin/flume-ng avro-client --conf conf -H localhost -p 41414 -F /etc/passwd -Dflume.root.logger=DEBUG,console
4、结果
这个时候，你可以看到以下消息：
2012-03-16 16:39:17,124 (main) [DEBUG - org.apache.flume.client.avro.AvroCLIClient.run(AvroCLIClient.java:175)] Finished
2012-03-16 16:39:17,127 (main) [DEBUG - org.apache.flume.client.avro.AvroCLIClient.run(AvroCLIClient.java:178)] Closing reader
2012-03-16 16:39:17,127 (main) [DEBUG - org.apache.flume.client.avro.AvroCLIClient.run(AvroCLIClient.java:183)] Closing transceiver
2012-03-16 16:39:17,129 (main) [DEBUG - org.apache.flume.client.avro.AvroCLIClient.main(AvroCLIClient.java:73)] Exiting
在前面那个开启flume server的窗口，可以看到如下消息：
2012-03-16 16:39:16,738 (New I/O server boss #1 ([id: 0x49e808ca, /0:0:0:0:0:0:0:0:41414])) [INFO - org.apache.avro.ipc.NettyServer$NettyServerAvroHandler.handleUpstream(NettyServer.java:123)] [id: 0x0b92a848, /1
27.0.0.1:39577 => /127.0.0.1:41414] OPEN
2012-03-16 16:39:16,742 (New I/O server worker #1-1) [INFO - org.apache.avro.ipc.NettyServer$NettyServerAvroHandler.handleUpstream(NettyServer.java:123)] [id: 0x0b92a848, /127.0.0.1:39577 => /127.0.0.1:41414] BOU
ND: /127.0.0.1:41414
2012-03-16 16:39:16,742 (New I/O server worker #1-1) [INFO - org.apache.avro.ipc.NettyServer$NettyServerAvroHandler.handleUpstream(NettyServer.java:123)] [id: 0x0b92a848, /127.0.0.1:39577 => /127.0.0.1:41414] CON
NECTED: /127.0.0.1:39577
2012-03-16 16:39:17,129 (New I/O server worker #1-1) [INFO - org.apache.avro.ipc.NettyServer$NettyServerAvroHandler.handleUpstream(NettyServer.java:123)] [id: 0x0b92a848, /127.0.0.1:39577 :> /127.0.0.1:41414] DISCONNECTED
2012-03-16 16:39:17,129 (New I/O server worker #1-1) [INFO - org.apache.avro.ipc.NettyServer$NettyServerAvroHandler.handleUpstream(NettyServer.java:123)] [id: 0x0b92a848, /127.0.0.1:39577 :> /127.0.0.1:41414] UNBOUND
2012-03-16 16:39:17,129 (New I/O server worker #1-1) [INFO - org.apache.avro.ipc.NettyServer$NettyServerAvroHandler.handleUpstream(NettyServer.java:123)] [id: 0x0b92a848, /127.0.0.1:39577 :> /127.0.0.1:41414] CLOSED
2012-03-16 16:39:17,302 (Thread-1) [INFO - org.apache.flume.sink.LoggerSink.process(LoggerSink.java:68)] Event: { headers:{} body:[B@5c1ae90c }
2012-03-16 16:39:17,302 (Thread-1) [INFO - org.apache.flume.sink.LoggerSink.process(LoggerSink.java:68)] Event: { headers:{} body:[B@6aba4211 }
2012-03-16 16:39:17,302 (Thread-1) [INFO - org.apache.flume.sink.LoggerSink.process(LoggerSink.java:68)] Event: { headers:{} body:[B@6a47a0d4 }
2012-03-16 16:39:17,302 (Thread-1) [INFO - org.apache.flume.sink.LoggerSink.process(LoggerSink.java:68)] Event: { headers:{} body:[B@48ff4cf }
...
简单实例－将目录文件上传到HDFS
场景：将机器上的某个文件夹下的文件上传到HDFS上。
1、配置conf/flume.conf
# Define a memory channel called ch1 on agent1
agent1.channels.ch1.type = memory
# Define an Avro source called avro-source1 on agent1 and tell it
# to bind to 0.0.0.0:41414. Connect it to channel ch1.
agent1.sources.spooldir-source1.channels = ch1
agent1.sources.spooldir-source1.type = spooldir
agent1.sources.spooldir-source1.spoolDir=/home/hadoop/flume-1.7.0/tmpData
agent1.sources.spooldir-source1.bind = 0.0.0.0
agent1.sources.spooldir-source1.port = 41414
# Define a logger sink that simply logs all events it receives
# and connect it to the other end of the same channel.
agent1.sinks.hdfs-sink1.channel = ch1
agent1.sinks.hdfs-sink1.type = hdfs
agent1.sinks.hdfs-sink1.hdfs.path = hdfs://master:9000/test
agent1.sinks.hdfs-sink1.hdfs.filePrefix = events-
agent1.sinks.hdfs-sink1.hdfs.useLocalTimeStamp = true
agent1.sinks.hdfs-sink1.hdfs.round = true
agent1.sinks.hdfs-sink1.hdfs.roundValue = 10
# Finally, now that we've defined all of our components, tell
# agent1 which ones we want to activate.
agent1.channels = ch1
agent1.sources = spooldir-source1
agent1.sinks = hdfs-sink1
其中，/home/hadoop/flume-1.7.0/tmpData是我要上传的文件所在目录，也就是，我要将此文件夹下的文件都上传到HDFS上的hdfs://master:9000/test目录。
注意：
- 这样的配置会产生许多小文件，因为默认情况下，一个文件存储10个event，这个配置由rollCount控制，默认为10，此外还有一个参数为rollSize，这个是控制一个文件的大小，如果文件大于这个数值，就是另起一文件。
- 此时的文件名都是以event开头，如果想保留原来文件的名字，可以使用以下配置（其中，basenameHeader是相对source而言，filePrefix是相对sink而言，分别这样设置之后，上传到hdfs上的文件名就会变成“原始文件名.时间戳”）：
agent1.sources.spooldir-source1.basenameHeader = true
agent1.sinks.hdfs-sink1.hdfs.filePrefix = %{basename}
2、启动agent
使用以下命令启动agent：
bin/flume-ng agent --conf ./conf/ -f ./conf/flume.conf --name agent1 -Dflume.root.logger=DEBUG,console
3、查看结果
到Hadoop提供的WEB GUI界面可以看到刚刚上传的文件是否成功。
GUI界面地址为：http://master:50070/explorer.html#/test
其中，master为Hadoop的Namenode所在的机器名。
4、总结
在这个场景，需要将文件上传到HDFS上，会使用到几个Hadoop的jar包，分别是：
${HADOOP_HOME}share/hadoop/common/hadoop-common-2.4.0.jar
${HADOOP_HOME}share/hadoop/common/lib/commons-configuration-1.6.jar
${HADOOP_HOME}share/hadoop/common/lib/hadoop-auth-2.4.0.jar
${HADOOP_HOME}share/hadoop/hdfs/hadoop-hdfs-2.4.0.jar
异常
Failed to start agent because dependencies were not found in classpath. Error follows. java.lang.NoClassDefFoundError org/apache/hadoop/io/SequenceFile$CompressionType
2016-11-03 14:49:35,278 (conf-file-poller-0) [ERROR - org.apache.flume.node.PollingPropertiesFileConfigurationProvider$FileWatcherRunnable.run(PollingPropertiesFileConfigurationProvider.java:146)] Failed to start agent because dependencies were not found in classpath. Error follows.
java.lang.NoClassDefFoundError: org/apache/hadoop/io/SequenceFile$CompressionType
问题原因：缺少依赖包，这个依赖包是以下jar文件：
${HADOOP_HOME}share/hadoop/common/hadoop-common-2.4.0.jar
解决方法：找到这个jar文件，copy到flume安装目录下的lib目录下就ok了。
java.lang.NullPointerException: Expected timestamp in the Flume event headers, but it was null
2016-11-03 16:32:06,741 (SinkRunner-PollingRunner-DefaultSinkProcessor) [ERROR - org.apache.flume.sink.hdfs.HDFSEventSink.process(HDFSEventSink.java:447)] process failed
java.lang.NullPointerException: Expected timestamp in the Flume event headers, but it was null
at com.google.common.base.Preconditions.checkNotNull(Preconditions.java:204)
at org.apache.flume.formatter.output.BucketPath.replaceShorthand(BucketPath.java:256)
at org.apache.flume.formatter.output.BucketPath.escapeString(BucketPath.java:465)
at org.apache.flume.sink.hdfs.HDFSEventSink.process(HDFSEventSink.java:368)
at org.apache.flume.sink.DefaultSinkProcessor.process(DefaultSinkProcessor.java:67)
at org.apache.flume.SinkRunner$PollingRunner.run(SinkRunner.java:145)
at java.lang.Thread.run(Thread.java:745)
解决方法：
编辑conf/flume.conf文件，其中agent1，sink1替换成你自己的agent和sink
agent1.sinks.sink1.hdfs.useLocalTimeStamp = true
java.lang.NoClassDefFoundError: org/apache/commons/configuration/Configuration
2016-11-03 16:32:55,594 (SinkRunner-PollingRunner-DefaultSinkProcessor) [ERROR - org.apache.flume.sink.hdfs.HDFSEventSink.process(HDFSEventSink.java:447)] process failed
java.lang.NoClassDefFoundError: org/apache/commons/configuration/Configuration
at org.apache.hadoop.metrics2.lib.DefaultMetricsSystem.<init>(DefaultMetricsSystem.java:38)
at org.apache.hadoop.metrics2.lib.DefaultMetricsSystem.<clinit>(DefaultMetricsSystem.java:36)
at org.apache.hadoop.security.UserGroupInformation$UgiMetrics.create(UserGroupInformation.java:106)
at org.apache.hadoop.security.UserGroupInformation.<clinit>(UserGroupInformation.java:208)
at org.apache.hadoop.fs.FileSystem$Cache$Key.<init>(FileSystem.java:2554)
at org.apache.hadoop.fs.FileSystem$Cache$Key.<init>(FileSystem.java:2546)
at org.apache.hadoop.fs.FileSystem$Cache.get(FileSystem.java:2412)
at org.apache.hadoop.fs.FileSystem.get(FileSystem.java:368)
at org.apache.hadoop.fs.Path.getFileSystem(Path.java:296)
at org.apache.flume.sink.hdfs.BucketWriter$1.call(BucketWriter.java:240)
at org.apache.flume.sink.hdfs.BucketWriter$1.call(BucketWriter.java:232)
at org.apache.flume.sink.hdfs.BucketWriter$9$1.run(BucketWriter.java:668)
at org.apache.flume.auth.SimpleAuthenticator.execute(SimpleAuthenticator.java:50)
at org.apache.flume.sink.hdfs.BucketWriter$9.call(BucketWriter.java:665)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.ClassNotFoundException: org.apache.commons.configuration