On 08/11/2010 08:08 PM, Aaron Kimball wrote:
On Wed, Aug 11, 2010 at 3:13 PM, David Rosenstrauch<dar...@darose.net>wrote:
What's the preferred way to submit a job these days?
org.apache.hadoop.mapreduce.Job.submit() ? Or
org.apache.hadoop.mapred.JobClient.runJob()? Or does it even matter? (i.e.,
is there any difference between them?)
If you're using the old API (e.g., you're filling out o.a.h.mapred.JobConf,
and implementing o.a.h.mapred.Mapper) then you use JobClient.runJob(). If
you're using the new API (o.a.h.mapreduce.Job, o.a.h.mapreduce.Mapper), then
you use Job.waitForCompletion().
You can't mix'n'match; your job has to be entirely "old style" or entirely
"new style." Some programs use one, some use the other.
OK, so I'm not insane then. :-) That's how I thought it worked.
On a related note, if there's actually no difference between the 2 methods,
would anybody have any idea what could make the "mapred.job.tracker" setting
on a job Configuration get ignored? (I currently have it set to
"hdfs://<hadoop_job_tracker_host_name>:9001".)
There's a reason that's being ignored :) That is not a jobtracker address.
Assuming you've configured your namenode and your jobtracker on the same
machine, then your fs.default.name should be hdfs://hdfs.host.name:port, and
mapred.job.tracker should just be jt.host.name:port
The port numbers in these two cases will be different.
Hmmmm ... OK. Not sure I understand why the syntax is different for
thosee 2 settings, but I'll give that a shot and see if it fixes the
problem.
Thanks much for the help!
DR
