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我终于能够在 Hadoop 上启动 map-reduce 作业(在单个 debian 机器上运行)。但是,map reduce 作业总是失败并出现以下错误:

hadoopmachine@debian:~$ ./hadoop-1.0.1/bin/hadoop jar hadooptest/main.jar nl.mydomain.hadoop.debian.test.Main /user/hadoopmachine/input /user/hadoopmachine/output
Warning: $HADOOP_HOME is deprecated.

12/04/03 07:29:35 WARN mapred.JobClient: Use GenericOptionsParser for parsing the arguments. Applications should implement Tool for the same.
****hdfs://localhost:9000/user/hadoopmachine/input
12/04/03 07:29:35 INFO input.FileInputFormat: Total input paths to process : 1
12/04/03 07:29:35 INFO mapred.JobClient: Running job: job_201204030722_0002
12/04/03 07:29:36 INFO mapred.JobClient:  map 0% reduce 0%
12/04/03 07:29:41 INFO mapred.JobClient: Task Id : attempt_201204030722_0002_m_000002_0, Status : FAILED
Error initializing attempt_201204030722_0002_m_000002_0:
ENOENT: No such file or directory
at org.apache.hadoop.io.nativeio.NativeIO.chmod(Native Method)
at org.apache.hadoop.fs.FileUtil.execSetPermission(FileUtil.java:692)
at org.apache.hadoop.fs.FileUtil.setPermission(FileUtil.java:647)
at org.apache.hadoop.fs.RawLocalFileSystem.setPermission(RawLocalFileSystem.java:509)
at org.apache.hadoop.fs.RawLocalFileSystem.mkdirs(RawLocalFileSystem.java:344)
at org.apache.hadoop.mapred.JobLocalizer.initializeJobLogDir(JobLocalizer.java:239)
at org.apache.hadoop.mapred.DefaultTaskController.initializeJob(DefaultTaskController.java:196)
at org.apache.hadoop.mapred.TaskTracker$4.run(TaskTracker.java:1226)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:416)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1093)
at org.apache.hadoop.mapred.TaskTracker.initializeJob(TaskTracker.java:1201)
at org.apache.hadoop.mapred.TaskTracker.localizeJob(TaskTracker.java:1116)
at org.apache.hadoop.mapred.TaskTracker$5.run(TaskTracker.java:2404)
at java.lang.Thread.run(Thread.java:636)

12/04/03 07:29:41 WARN mapred.JobClient: Error reading task outputhttp://localhost:50060/tasklog?plaintext=true&attemptid=attempt_201204030722_0002_m_000002_0&filter=stdout
12/04/03 07:29:41 WARN mapred.JobClient: Error reading task outputhttp://localhost:50060/tasklog?plaintext=true&attemptid=attempt_201204030722_0002_m_000002_0&filter=stderr

不幸的是,它只说:“ENOENT:没有这样的文件或目录”,它没有说明它实际尝试访问的目录。ping localhost 有效,并且输入目录确实存在。罐子的位置也正确。

谁能给我一个关于如何修复这个错误的指针,或者如何找出 Hadoop 试图访问的文件?

我在 Hadoop 邮件列表中发现了几个类似的问题,但没有任何回应......

谢谢!

PS mapred.local.dir 的配置如下所示(在 mapred-site.xml 中):

<property>
  <name>mapred.local.dir</name>
  <value>/home/hadoopmachine/hadoop_data/mapred</value>
  <final>true</final>
</property>

根据要求,ps auxww | 的输出 grep TaskTracker 是:

1000      4249  2.2  0.8 1181992 30176 ?       Sl   12:09   0:00
/usr/lib/jvm/java-6-openjdk/bin/java -Dproc_tasktracker -Xmx1000m -Dhadoop.log.dir=/home/hadoopmachine/hadoop-1.0.1/libexec/../logs
-Dhadoop.log.file=hadoop-hadoopmachine-tasktracker-debian.log -Dhadoop.home.dir=/home/hadoopmachine/hadoop-1.0.1/libexec/.. 
-Dhadoop.id.str=hadoopmachine -Dhadoop.root.logger=INFO,DRFA -Dhadoop.security.logger=INFO,NullAppender
-Djava.library.path=/home/hadoopmachine/hadoop-1.0.1/libexec/../lib/native/Linux-i386-32 
-Dhadoop.policy.file=hadoop-policy.xml -classpath [ommitted very long list of jars] org.apache.hadoop.mapred.TaskTracker
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1 回答 1

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从作业跟踪器中,确定该任务在哪个 hadoop 节点上执行。SSH 到那个节点并确定hadoop.log.dir目录的位置(检查这个节点的 mapred-site.xml)——我的猜测是 hadoop 用户没有在这个文件夹中创建子目录的正确权限

它尝试创建的实际文件夹位于 ${hadoop.log.dir}/userlogs 文件夹下 - 检查此文件夹是否具有正确的权限

在您的情况下,查看 ps 输出,我猜这是您需要检查以下权限的文件夹:

/home/hadoopmachine/hadoop-1.0.1/libexec/../logs
于 2012-04-03T12:14:20.440 回答