Question

我在这里遵循这个例子，希望使用EC2 / S3 / EMR / R成功运行。 https://gist.github.com/406824

Streaming Step上的作业失败。以下是错误日志：

控制器：

2011-07-21T19:14:27.711Z INFO Fetching jar file.
2011-07-21T19:14:30.380Z INFO Working dir /mnt/var/lib/hadoop/steps/1
2011-07-21T19:14:30.380Z INFO Executing /usr/lib/jvm/java-6-sun/bin/java -cp /home/hadoop/conf:  /usr/lib/jvm/java-6-sun/lib/tools.jar:/home/hadoop:/home/hadoop/hadoop-0.20-core.jar:/home/hadoop/hadoop-0.20-tools.jar:/home/hadoop/lib/*:/home/hadoop/lib/jetty-ext/* -Xmx1000m -Dhadoop.log.dir=/mnt/var/log/hadoop/steps/1 -Dhadoop.log.file=syslog -Dhadoop.home.dir=/home/hadoop -Dhadoop.id.str=hadoop -Dhadoop.root.logger=INFO,DRFA -Djava.io.tmpdir=/mnt/var/lib/hadoop/steps/1/tmp -Djava.library.path=/home/hadoop/lib/native/Linux-i386-32 org.apache.hadoop.util.RunJar /home/hadoop/contrib/streaming/hadoop-streaming.jar -cacheFile s3n://emrexample21/calculatePiFunction.R#calculatePiFunction.R -input s3n://emrexample21/numberList.txt -output s3n://emrout/ -mapper s3n://emrexample21/mapper.R -reducer s3n://emrexample21/reducer.R
2011-07-21T19:16:12.057Z INFO Execution ended with ret val 1
2011-07-21T19:16:12.057Z WARN Step failed with bad retval
2011-07-21T19:16:14.185Z INFO Step created jobs: job_201107211913_0001

stderr的：

Streaming Command Failed!

标准输出：

packageJobJar: [/mnt/var/lib/hadoop/tmp/hadoop-unjar2368654264051498521/] [] /mnt/var/lib/hadoop/steps/2/tmp/streamjob1658200878131882888.jar tmpDir=null

系统日志：

2011-07-21 19:50:29,539 INFO org.apache.hadoop.mapred.JobClient (main): Default number of map tasks: 2
2011-07-21 19:50:29,539 INFO org.apache.hadoop.mapred.JobClient (main): Default number of reduce tasks: 15
2011-07-21 19:50:31,988 INFO com.hadoop.compression.lzo.GPLNativeCodeLoader (main): Loaded native gpl library
2011-07-21 19:50:31,999 INFO com.hadoop.compression.lzo.LzoCodec (main): Successfully loaded & initialized native-lzo library [hadoop-lzo rev 2334756312e0012cac793f12f4151bdaa1b4b1bb]
2011-07-21 19:50:33,040 INFO org.apache.hadoop.mapred.FileInputFormat (main): Total input paths to process : 1
2011-07-21 19:50:35,375 INFO org.apache.hadoop.streaming.StreamJob (main): getLocalDirs(): [/mnt/var/lib/hadoop/mapred]
2011-07-21 19:50:35,375 INFO org.apache.hadoop.streaming.StreamJob (main): Running job: job_201107211948_0001
2011-07-21 19:50:35,375 INFO org.apache.hadoop.streaming.StreamJob (main): To kill this job, run:
2011-07-21 19:50:35,375 INFO org.apache.hadoop.streaming.StreamJob (main): UNDEF/bin/hadoop job  -Dmapred.job.tracker=ip-10-203-50-161.ec2.internal:9001 -kill job_201107211948_0001
2011-07-21 19:50:35,376 INFO org.apache.hadoop.streaming.StreamJob (main): Tracking URL: http://ip-10-203-50-161.ec2.internal:9100/jobdetails.jsp?jobid=job_201107211948_0001
2011-07-21 19:50:36,566 INFO org.apache.hadoop.streaming.StreamJob (main):  map 0%  reduce 0%
2011-07-21 19:50:57,778 INFO org.apache.hadoop.streaming.StreamJob (main):  map 50%  reduce 0%
2011-07-21 19:51:09,839 INFO org.apache.hadoop.streaming.StreamJob (main):  map 100%  reduce 0%
2011-07-21 19:51:12,852 INFO org.apache.hadoop.streaming.StreamJob (main):  map 100%  reduce 1%
2011-07-21 19:51:15,864 INFO org.apache.hadoop.streaming.StreamJob (main):  map 100%  reduce 3%
2011-07-21 19:51:18,875 INFO org.apache.hadoop.streaming.StreamJob (main):  map 100%  reduce 0%
2011-07-21 19:52:12,454 INFO org.apache.hadoop.streaming.StreamJob (main):  map 100%  reduce 100%
2011-07-21 19:52:12,455 INFO org.apache.hadoop.streaming.StreamJob (main): To kill this job, run:
2011-07-21 19:52:12,455 INFO org.apache.hadoop.streaming.StreamJob (main): UNDEF/bin/hadoop job  -Dmapred.job.tracker=ip-10-203-50-161.ec2.internal:9001 -kill job_201107211948_0001
2011-07-21 19:52:12,456 INFO org.apache.hadoop.streaming.StreamJob (main): Tracking URL: http://ip-10-203-50-161.ec2.internal:9100/jobdetails.jsp?jobid=job_201107211948_0001
2011-07-21 19:52:12,456 ERROR org.apache.hadoop.streaming.StreamJob (main): Job not Successful!
2011-07-21 19:52:12,456 INFO org.apache.hadoop.streaming.StreamJob (main): killJob...

Answer 1

我是您尝试运行的代码的作者。它被写成关于R和EMR的概念证明。使用该方法制作真正有用的代码非常困难。通过该方法正常工作所需的所有手动步骤将R代码提交给EMR是一项繁琐的工作。

为了解决这个问题，我后来编写了Segue package，它将所有比特加载到S3中以及在Hadoop节点上更新R版本。 Jeffry Breen写了一篇关于使用Segue的blog post。看看它，看看它是否更容易使用。

修改

我至少应该提供一些关于在EMR / Hadoop流中调试R代码的技巧：

1）从Hadoop日志调试R代码几乎是不可能的。根据我的经验，我真的必须设置一个EMR集群，登录它，并从R中手动运行代码。这需要使用定义的密钥启动集群。我通常在单个节点集群上执行此操作以进行调试并使用非常小的数据集。没有意义只是为了调试而运行多个节点。

2）在EMR节点上的R中以交互方式运行作业需要在Hadoop节点上的/ home / hadoop /目录中包含任何输入文件。最简单的方法是scp您需要的所有文件到集群。

3）在做1＆amp;之前2，使用相同的方法在本地测试代码

4）一旦你认为R代码有效，你应该能够在你的Hadoop机器上执行此操作

cat numberList.txt | ./mapper.R | sort | ./reducer.R

它应该运行。如果您没有使用映射器或减速器，则可以用cat替换它们。我在这个例子中使用numberList.txt，因为在我的github上的代码中是输入文件名。

流命令失败！使用Elastic Map Reduce / S3和R时出错

1 个答案: