After you unleashed your mapreduce job, how could you monitor the progress of your map reduce jobs beyond the standard output from the hadoop it self.
An easy to monitor any types of map reduce job running on the cluster is go to the url: http://<namenode>:8088, which is the application dashboard for YARN. From there, you can dive into the nuts and bolts of each job, like how many mapper/reducers there are, how much progress they have made..etc.
If you are in the command line and hard-core enough to prefer command line. You can use the `hadoop job` command to manipulate map reduce jobs.
datafireball 