关于ubuntu：简单Hadoop Map Reduce中的错误


Error in simple Hadoop Map Reduce

我尝试运行hadoop地图来减少字数统计问题。据我所知，我正确设置了HDFS以及所有内容。

执行时，

在尝试运行一个简单的字数统计问题时出现此错误。我是Hadoop的新手。任何解决方法的帮助将不胜感激。

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13/06/13 20:21:17 INFO input.FileInputFormat: Total input paths to process : 4
13/06/13 20:21:17 INFO util.NativeCodeLoader: Loaded the native-hadoop library
13/06/13 20:21:17 WARN snappy.LoadSnappy: Snappy native library not loaded
13/06/13 20:21:17 INFO mapred.JobClient: Running job: job_201306131940_0007
13/06/13 20:21:18 INFO mapred.JobClient:  map 0% reduce 0%
13/06/13 20:21:21 INFO mapred.JobClient: Task Id : attempt_201306131940_0007_m_000005_0, Status : FAILED
java.lang.Throwable: Child Error
at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:271)
Caused by: java.io.IOException: Creation of symlink from /home/vraju/Desktop/hadoop/libexec/../logs/userlogs/job_201306131940_0007/attempt_201306131940_0007_m_000005_0 to /app/hadoop/tmp/mapred/local/userlogs/job_201306131940_0007/attempt_201306131940_0007_m_000005_0 failed.
at org.apache.hadoop.mapred.TaskLog.createTaskAttemptLogDir(TaskLog.java:110)
at org.apache.hadoop.mapred.DefaultTaskController.createLogDir(DefaultTaskController.java:71)
at org.apache.hadoop.mapred.TaskRunner.prepareLogFiles(TaskRunner.java:316)
at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:228)

13/06/13 20:21:21 WARN mapred.JobClient: Error reading task outputhttp://ubuntu:50060/tasklog?plaintext=true&attemptid=attempt_201306131940_0007_m_000005_0&filter=stdout
13/06/13 20:21:21 WARN mapred.JobClient: Error reading task outputhttp://ubuntu:50060/tasklog?plaintext=true&attemptid=attempt_201306131940_0007_m_000005_0&filter=stderr
13/06/13 20:21:24 INFO mapred.JobClient: Task Id : attempt_201306131940_0007_m_000005_1, Status : FAILED
java.lang.Throwable: Child Error
at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:271)
Caused by: java.io.IOException: Creation of symlink from /home/vraju/Desktop/hadoop/libexec/../logs/userlogs/job_201306131940_0007/attempt_201306131940_0007_m_000005_1 to /app/hadoop/tmp/mapred/local/userlogs/job_201306131940_0007/attempt_201306131940_0007_m_000005_1 failed.
at org.apache.hadoop.mapred.TaskLog.createTaskAttemptLogDir(TaskLog.java:110)
at org.apache.hadoop.mapred.DefaultTaskController.createLogDir(DefaultTaskController.java:71)
at org.apache.hadoop.mapred.TaskRunner.prepareLogFiles(TaskRunner.java:316)
at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:228)

13/06/13 20:21:25 WARN mapred.JobClient: Error reading task outputhttp://ubuntu:50060/tasklog?plaintext=true&attemptid=attempt_201306131940_0007_m_000005_1&filter=stdout
13/06/13 20:21:25 WARN mapred.JobClient: Error reading task outputhttp://ubuntu:50060/tasklog?plaintext=true&attemptid=attempt_201306131940_0007_m_000005_1&filter=stderr
13/06/13 20:21:28 INFO mapred.JobClient: Task Id : attempt_201306131940_0007_m_000005_2, Status : FAILED
java.lang.Throwable: Child Error
at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:271)
Caused by: java.io.IOException: Creation of symlink from /home/vraju/Desktop/hadoop/libexec/../logs/userlogs/job_201306131940_0007/attempt_201306131940_0007_m_000005_2 to /app/hadoop/tmp/mapred/local/userlogs/job_201306131940_0007/attempt_201306131940_0007_m_000005_2 failed.
at org.apache.hadoop.mapred.TaskLog.createTaskAttemptLogDir(TaskLog.java:110)
at org.apache.hadoop.mapred.DefaultTaskController.createLogDir(DefaultTaskController.java:71)
at org.apache.hadoop.mapred.TaskRunner.prepareLogFiles(TaskRunner.java:316)
at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:228)

13/06/13 20:21:28 WARN mapred.JobClient: Error reading task outputhttp://ubuntu:50060/tasklog?plaintext=true&attemptid=attempt_201306131940_0007_m_000005_2&filter=stdout
13/06/13 20:21:28 WARN mapred.JobClient: Error reading task outputhttp://ubuntu:50060/tasklog?plaintext=true&attemptid=attempt_201306131940_0007_m_000005_2&filter=stderr
13/06/13 20:21:34 INFO mapred.JobClient: Task Id : attempt_201306131940_0007_m_000004_0, Status : FAILED
java.lang.Throwable: Child Error
at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:271)
Caused by: java.io.IOException: Creation of symlink from /home/vraju/Desktop/hadoop/libexec/../logs/userlogs/job_201306131940_0007/attempt_201306131940_0007_m_000004_0 to /app/hadoop/tmp/mapred/local/userlogs/job_201306131940_0007/attempt_201306131940_0007_m_000004_0 failed.
at org.apache.hadoop.mapred.TaskLog.createTaskAttemptLogDir(TaskLog.java:110)
at org.apache.hadoop.mapred.DefaultTaskController.createLogDir(DefaultTaskController.java:71)
at org.apache.hadoop.mapred.TaskRunner.prepareLogFiles(TaskRunner.java:316)
at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:228)

13/06/13 20:21:34 WARN mapred.JobClient: Error reading task outputhttp://ubuntu:50060/tasklog?plaintext=true&attemptid=attempt_201306131940_0007_m_000004_0&filter=stdout
13/06/13 20:21:34 WARN mapred.JobClient: Error reading task outputhttp://ubuntu:50060/tasklog?plaintext=true&attemptid=attempt_201306131940_0007_m_000004_0&filter=stderr
13/06/13 20:21:37 INFO mapred.JobClient: Task Id : attempt_201306131940_0007_m_000004_1, Status : FAILED
java.lang.Throwable: Child Error
at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:271)
Caused by: java.io.IOException: Creation of symlink from /home/vraju/Desktop/hadoop/libexec/../logs/userlogs/job_201306131940_0007/attempt_201306131940_0007_m_000004_1 to /app/hadoop/tmp/mapred/local/userlogs/job_201306131940_0007/attempt_201306131940_0007_m_000004_1 failed.
at org.apache.hadoop.mapred.TaskLog.createTaskAttemptLogDir(TaskLog.java:110)
at org.apache.hadoop.mapred.DefaultTaskController.createLogDir(DefaultTaskController.java:71)
at org.apache.hadoop.mapred.TaskRunner.prepareLogFiles(TaskRunner.java:316)
at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:228)

13/06/13 20:21:37 WARN mapred.JobClient: Error reading task outputhttp://ubuntu:50060/tasklog?plaintext=true&attemptid=attempt_201306131940_0007_m_000004_1&filter=stdout
13/06/13 20:21:37 WARN mapred.JobClient: Error reading task outputhttp://ubuntu:50060/tasklog?plaintext=true&attemptid=attempt_201306131940_0007_m_000004_1&filter=stderr
13/06/13 20:21:40 INFO mapred.JobClient: Task Id : attempt_201306131940_0007_m_000004_2, Status : FAILED
java.lang.Throwable: Child Error
at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:271)
Caused by: java.io.IOException: Creation of symlink from /home/vraju/Desktop/hadoop/libexec/../logs/userlogs/job_201306131940_0007/attempt_201306131940_0007_m_000004_2 to /app/hadoop/tmp/mapred/local/userlogs/job_201306131940_0007/attempt_201306131940_0007_m_000004_2 failed.
at org.apache.hadoop.mapred.TaskLog.createTaskAttemptLogDir(TaskLog.java:110)
at org.apache.hadoop.mapred.DefaultTaskController.createLogDir(DefaultTaskController.java:71)
at org.apache.hadoop.mapred.TaskRunner.prepareLogFiles(TaskRunner.java:316)
at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:228)
13/06/13 20:21:40 WARN mapred.JobClient: Error reading task outputhttp://ubuntu:50060/tasklog?plaintext=true&attemptid=attempt_201306131940_0007_m_000004_2&filter=stdout
13/06/13 20:21:40 WARN mapred.JobClient: Error reading task outputhttp://ubuntu:50060/tasklog?plaintext=true&attemptid=attempt_201306131940_0007_m_000004_2&filter=stderr
13/06/13 20:21:43 INFO mapred.JobClient: Job complete: job_201306131940_0007
13/06/13 20:21:43 INFO mapred.JobClient: Counters: 4
13/06/13 20:21:43 INFO mapred.JobClient:   Job Counters
13/06/13 20:21:43 INFO mapred.JobClient:     SLOTS_MILLIS_MAPS=24100
13/06/13 20:21:43 INFO mapred.JobClient:     Total time spent by all reduces waiting after reserving slots (ms)=0
13/06/13 20:21:43 INFO mapred.JobClient:     Total time spent by all maps waiting after reserving slots (ms)=0
13/06/13 20:21:43 INFO mapred.JobClient:     SLOTS_MILLIS_REDUCES=0
相关讨论

当您获得

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java.lang.Throwable: Child Error
at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:271)

似乎为任务跟踪器分配的内存大于节点的实际内存。

您可以在此处获得更多信息

在尝试执行相同的操作时，我遇到了完全相同的错误-对简单文本执行字数统计。
就我而言，我解决了更改Hadoop依赖的JDK版本的问题。我正在使用Hadoop 1.2.1，并且在网上发现它的首选Java版本是1.6

我遇到了这个问题，但这是程序包名称问题。

我正在使用Maven进行编译。在pom.xml中，我们有<groupId>GROUPNAME</groupId>

我所有的软件包都必须在GROUPNAME内，例如GROUPNAME.newpackage.ClassName

然后，它起作用了。

我遇到了一整天都解决的问题，直到我在线找到一个解决方案，即VirtualBox的共享目录中不支持创建符号链接的操作。尝试将hadoop目录移至/ usr / local能否解决您的问题。