flume保存文件到hdfs的时候报错

flume配置sink向hdfs中写入文件，在启动的时候遇到的报错问题

1. Failed to start agent because dependencies were not found in classpath. Error follows.

java.lang.NoClassDefFoundError: org/apache/hadoop/io/SequenceFile$CompressionType

[ERROR - org.apache.flume.node.PollingPropertiesFileConfigurationProvider$FileWatcherRunnable.run(PollingPropertiesFileConfigurationProvider.java:145)] Failed to start agent because dependencies were not found in classpath. Error follows.java.lang.NoClassDefFoundError: org/apache/hadoop/io/SequenceFile$CompressionType        at org.apache.flume.sink.hdfs.HDFSEventSink.configure(HDFSEventSink.java:239)        at org.apache.flume.conf.Configurables.configure(Configurables.java:41)        at org.apache.flume.node.AbstractConfigurationProvider.loadSinks(AbstractConfigurationProvider.java:413)        at org.apache.flume.node.AbstractConfigurationProvider.getConfiguration(AbstractConfigurationProvider.java:98)        at org.apache.flume.node.PollingPropertiesFileConfigurationProvider$FileWatcherRunnable.run(PollingPropertiesFileConfigurationProvider.java:140)        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)        at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:304)        at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:178)        at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293)        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)        at java.lang.Thread.run(Thread.java:745)Caused by: java.lang.ClassNotFoundException: org.apache.hadoop.io.SequenceFile$CompressionType        at java.net.URLClassLoader$1.run(URLClassLoader.java:366)        at java.net.URLClassLoader$1.run(URLClassLoader.java:355)        at java.security.AccessController.doPrivileged(Native Method)        at java.net.URLClassLoader.findClass(URLClassLoader.java:354)        at java.lang.ClassLoader.loadClass(ClassLoader.java:425)        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)        at java.lang.ClassLoader.loadClass(ClassLoader.java:358)        ... 12 more

这是因为没有相应的的jar包导致的， 进入到/hadoop/share/hadoop/common/*.jar 和/hadoop/share/hadoop/common/lib/*.jar 拷贝到flume安装目录的lib下就可以。

2.  HDFS IO error

java.io.IOException: No FileSystem for scheme: hdfs

[WARN - org.apache.flume.sink.hdfs.HDFSEventSink.process(HDFSEventSink.java:455)] HDFS IO errorjava.io.IOException: No FileSystem for scheme: hdfs        at org.apache.hadoop.fs.FileSystem.getFileSystemClass(FileSystem.java:2385)        at org.apache.hadoop.fs.FileSystem.createFileSystem(FileSystem.java:2392)        at org.apache.hadoop.fs.FileSystem.access$200(FileSystem.java:89)        at org.apache.hadoop.fs.FileSystem$Cache.getInternal(FileSystem.java:2431)        at org.apache.hadoop.fs.FileSystem$Cache.get(FileSystem.java:2413)        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:243)        at org.apache.flume.sink.hdfs.BucketWriter$1.call(BucketWriter.java:235)        at org.apache.flume.sink.hdfs.BucketWriter$9$1.run(BucketWriter.java:679)        at org.apache.flume.auth.SimpleAuthenticator.execute(SimpleAuthenticator.java:50)        at org.apache.flume.sink.hdfs.BucketWriter$9.call(BucketWriter.java:676)        at java.util.concurrent.FutureTask.run(FutureTask.java:262)        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)        at java.lang.Thread.run(Thread.java:745)

运行的时候还是会报找不到hdfs文件的错误，进入到hadoop的安装目录找到/share/hadoop/hdfs/hadoop-hdfs-2.4.1.jar 同样拷贝到flume的安装目录的lib下。再启动就可以了。