Running MRv1 jobs through Eclipse

[Praveen Sripati <pr...@gmail.com>]

Hi,

I am trying to run MRv1 jobs in Eclipse.

I have been able to run in Local (Standalone) Mode, but not in
Pseudo-Distributed Mode. In the Pseudo-Distributed Mode, the below exception
is thrown in the Eclipse console. I see a similar exception in the
tasktracker log file also. I start the
namenode/datanode/jobtracker/tasktracker from the terminal and the
MaxTemperatureDriver from the Eclipse.

I am getting familiar with Hadoop and would like to run MR jobs in Eclipse,
so that I can put breakpoint and go through the code. I found a couple of
wiki entries on apache.org, but all of them are on how to get the code into
Eclipse from SVN and compile it and not how to run and debug MR jobs through
Eclipse. Has anyone tried executing MR jobs through Eclipse? And what are
the practices followed for the development of Hadoop (does everything happen
from the command line through the use of println only)?

11/10/03 13:10:05 INFO mapreduce.Job:  map 0% reduce 0%
11/10/03 13:10:36 INFO mapreduce.Job: Task Id :
attempt_201110031252_0002_m_000001_0, Status : FAILED
java.lang.RuntimeException: java.lang.RuntimeException:
java.lang.ClassNotFoundException: MaxTemperatureReducer
    at
org.apache.hadoop.conf.Configuration.getClass(Configuration.java:1160)
    at org.apache.hadoop.mapred.JobConf.getCombinerClass(JobConf.java:1050)
    at org.apache.hadoop.mapred.Task$CombinerRunner.create(Task.java:1306)
    at
org.apache.hadoop.mapred.MapTask$MapOutputBuffer.<init>(MapTask.java:850)
    at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:389)
    at org.apache.hadoop.mapred.MapTask.run(MapTask.java:330)
    at org.apache.hadoop.mapred.Child$4.run(Child.java:217)
    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:742)
    at org.apache.hadoop.mapred.Child.main(Child.java:211)
Caused by: java.lang.RuntimeException: java.lang.ClassNotFoundException:
MaxTemperatureReducer
    at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:1128

Thanks,
Praveen