在Hadoop中执行python mapreduce任务时出错？

Question

I have written mapper and reducer for the wordcount example in python. The scripts works fine as a standalone ones. but I get error when run in hadoop.

I am using hadoop2.2

Here is my command:

hadoop jar share/hadoop/tools/sources/hadoop-streaming*.jar -mapper wordmapper.py -reducer wordreducer.py -file wordmapper.py -file wordreducer.py -input /data -output/output/result7

Exception in thread "main" java.lang.ClassNotFoundException: share.hadoop.tools.sources.hadoop-streaming-2.2.0-test-sources.jar
    at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:249)
    at org.apache.hadoop.util.RunJar.main(RunJar.java:205)

how to fix this?

Answer 1

Can u please try it with

hadoop jar $HADOOP_PREFIX/hadoop/tools/sources/hadoop-streaming*.jar -mapper 'wordmapper.py' -reducer 'wordreducer.py' -file $CODE_FOLDER/wordmapper.py -file $CODE_FOLDER/wordreducer.py -input /data -output /output/result7

Where $HADOOP_PREFIX is folder location where the hadoop is placed on your machine. for eg./usr/local/ for my machine. If you can manually acces that location and check whether that jar is present.

And $CODE_FOLDER contains the code file where the script is saved.