Question

我有一个最近从CDH3升级运行CDH4的集群。 Hive目前工作得很好。但是我似乎无法让它运行简单的MR Streaming作业（版本1）。纱线已安装但未使用。这是命令行输入和输出

$ /usr/lib/hadoop/bin/hadoop jar /usr/lib/hadoop-0.20-mapreduce/contrib/streaming/hadoop-  streaming-2.0.0-mr1-cdh4.0.0.jar grep -input /input -output /output/ 'dfs[a-z.]+'

检查日志会显示：

packageJobJar: [/tmp/hadoop-hdfs/hadoop-unjar7491355516546899751/] [] /tmp/streamjob1375201380112960182.jar tmpDir=null
12/07/12 07:26:29 WARN mapred.JobClient: Use GenericOptionsParser for parsing the arguments. Applications should implement Tool for the same.
12/07/12 07:26:29 INFO util.NativeCodeLoader: Loaded the native-hadoop library
12/07/12 07:26:29 WARN snappy.LoadSnappy: Snappy native library is available
12/07/12 07:26:29 INFO snappy.LoadSnappy: Snappy native library loaded
12/07/12 07:26:29 INFO mapred.FileInputFormat: Total input paths to process : 3
12/07/12 07:26:29 INFO streaming.StreamJob: getLocalDirs(): [file:////data/hadoop-0.20/cache/mapred/mapred/local]
12/07/12 07:26:29 INFO streaming.StreamJob: Running job: job_201207120604_0018
12/07/12 07:26:29 INFO streaming.StreamJob: To kill this job, run:
12/07/12 07:26:29 INFO streaming.StreamJob: UNDEF/bin/hadoop job  -Dmapred.job.tracker=frost:54311 -kill job_201207120604_0018
12/07/12 07:26:29 INFO streaming.StreamJob: Tracking URL: >http://alpha:50030/jobdetails.jsp?jobid=job_201207120604_0018
12/07/12 07:26:30 INFO streaming.StreamJob:  map 0%  reduce 0%
12/07/12 07:26:57 INFO streaming.StreamJob:  map 100%  reduce 100%
12/07/12 07:26:57 INFO streaming.StreamJob: To kill this job, run:
12/07/12 07:26:57 INFO streaming.StreamJob: UNDEF/bin/hadoop job  -Dmapred.job.tracker=frost:54311 -kill job_201207120604_0018
12/07/12 07:26:57 INFO streaming.StreamJob: Tracking URL: >http://alpha:50030/jobdetails.jsp?jobid=job_201207120604_0018
12/07/12 07:26:57 ERROR streaming.StreamJob: Job not successful. Error: NA
12/07/12 07:26:57 INFO streaming.StreamJob: killJob...
Streaming Command Failed!

日志输出很多失败减少任务：

2012-07-12 07:26:46,785 INFO org.apache.hadoop.mapred.TaskInProgress: Error from attempt_201207120604_0018_m_000001_2: java.io.IOException: Type mismatch in key from map: expected org.apache.hadoop.io.Text, recieved org.apache.hadoop.io.LongWritable
    at org.apache.hadoop.mapred.MapTask$MapOutputBuffer.collect(MapTask.java:861)
    at org.apache.hadoop.mapred.MapTask$OldOutputCollector.collect(MapTask.java:501)
    at org.apache.hadoop.mapred.lib.IdentityMapper.map(IdentityMapper.java:38)
    at org.apache.hadoop.mapred.MapRunner.run(MapRunner.java:50)
    at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:393)
    at org.apache.hadoop.mapred.MapTask.run(MapTask.java:327)
    at org.apache.hadoop.mapred.Child$4.run(Child.java:270)
    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:1232)
    at org.apache.hadoop.mapred.Child.main(Child.java:264)

谢天谢地，卡特。

Answer 1

您可以查看生成的job.xml以查找您提交的作业（通过JobTracker Web界面），并查看映射器的定义值是什么？（mapreduce.map.class财产）。

从您包含的地图日志中，您可能已配置了身份映射器（因此LongWritable将作为输出键出现，而不是Text的作业定义值）：

键入地图中的键不匹配：期望org.apache.hadoop.io.Text，收到org.apache.hadoop.io.LongWritable

如果是这种情况，你需要查看2.0.0 hadoop的流代码（我没有立即动手），看看如何用你的参数启动hadoop-streaming-2.0.0-mr1-cdh4.0.0.jar jar将配置并运行作业

使用MR1 CDH4运行简单的MapReduce Streaming作业失败

1 个答案: