Hadoop Cluster – Do I need to copy my code on all machines before running a job?… here is a solution to the problem.
Hadoop Cluster – Do I need to copy my code on all machines before running a job?
That’s what confuses me, when I use the wordcount example I leave the code at master and let him do things with slave and it works fine
But when I run my code, it starts failing on slaves, giving strange errors like
Traceback (most recent call last):
File "/app/hadoop/tmp/mapred/local/taskTracker/hduser/jobcache/job_201110250901_0005/attempt_201110250901_0005_m_000001_1/work/./mapper.py", line 55, in <module>
from src.utilities import utilities
ImportError: No module named src.utilities
java.lang.RuntimeException: PipeMapRed.waitOutputThreads(): subprocess failed with code 1
at org.apache.hadoop.streaming.PipeMapRed.waitOutputThreads(PipeMapRed.java:311)
at org.apache.hadoop.streaming.PipeMapRed.mapRedFinished(PipeMapRed.java:545)
at org.apache.hadoop.streaming.PipeMapper.map(PipeMapper.java:121)
at org.apache.hadoop.mapred.MapRunner.run(MapRunner.java:50)
at org.apache.hadoop.streaming.PipeMapRunner.run(PipeMapRunner.java:36)
at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:436)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:372)
at org.apache.hadoop.mapred.Child$4.run(Child.java:261)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:396)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1059)
at org.apache.hadoop.mapred.Child.main(Child.java:255)
java.lang.RuntimeException: PipeMapRed.waitOutputThreads(): subprocess failed with code 1
at org.apache.hadoop.streaming.PipeMapRed.waitOutputThreads(PipeMapRed.java:311)
at org.apache.hadoop.streaming.PipeMapRed.mapRedFinished(PipeMapRed.java:545)
at org.apache.hadoop.streaming.PipeMapper.close(PipeMapper.java:132)
at org.apache.hadoop.mapred.MapRunner.run(MapRunner.java:57)
at org.apache.hadoop.streaming.PipeMapRunner.run(PipeMapRunner.java:36)
at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:436)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:372)
at org.apache.hadoop.mapred.Child$4.run(Child.java:261)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:396)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1059)
at org.apache.hadoop.mapred.Child.main(Child.java:255)
Since I don’t have code on the path, am I doing something wrong?
Thanks
Solution
To use Hadoop streaming, you must use -file Copy the code/dependency flags if the code is not on the target machine. Ensure that the map/reduce file and its dependencies are specified in the Hadoop streaming command.
$HADOOP_HOME/bin/hadoop jar $HADOOP_HOME/hadoop-streaming.jar \
-input myInputDirs \
-output myOutputDir \
-mapper myPythonScript.py \
-reducer /bin/wc \
-file myPythonScript.py \
-file myDictionary.txt \