7 May 2011 22:56
Problem debugging MapReduce job under Windows
Hello,
I am trying to debug a Hadoop MapReduce job under Eclipse in Windows and I am running into a problem when the
Hadoop framework tries to set up the staging directory (see the stack trace below) and change its
permissions to 700. It is doing it in RawLocalFileSystem.setPermissions by calling
java.io.File.setReadable(false, false), but under Windows this always fails, since you're not
allowed to set readable to false. Is there a workaround for this to enable debugging in a Windows
environment, or is such a scenario simply not possible?
(I am using Windows 7, Hadoop 0.20.2, Java 6. I have Cygwin installed, but in this case it is not using it,
since it is making the system call directly.)
Thanks,
Iwona
java.io.IOException: Failed to set permissions of path:
file:/tmp/hadoop-iwonabb/mapred/staging/iwonabb-1931875024/.staging to 0700
at org.apache.hadoop.fs.RawLocalFileSystem.checkReturnValue(RawLocalFileSystem.java:526)
at org.apache.hadoop.fs.RawLocalFileSystem.setPermission(RawLocalFileSystem.java:500)
at org.apache.hadoop.fs.RawLocalFileSystem.mkdirs(RawLocalFileSystem.java:310)
at org.apache.hadoop.fs.FilterFileSystem.mkdirs(FilterFileSystem.java:189)
at org.apache.hadoop.mapreduce.JobSubmissionFiles.getStagingDir(JobSubmissionFiles.java:116)
at org.apache.hadoop.mapred.JobClient$2.run(JobClient.java:799)
at org.apache.hadoop.mapred.JobClient$2.run(JobClient.java:793)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Unknown Source)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1063)
at org.apache.hadoop.mapred.JobClient.submitJobInternal(JobClient.java:793)
at org.apache.hadoop.mapreduce.Job.submit(Job.java:465)
at org.apache.hadoop.mapreduce.Job.waitForCompletion(Job.java:495)
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