Now we will start the WMRServer daemon for the first time. Similar to Hadoop itself, WMRServer is controlled by scripts named start-wmr.sh and stop-wmr.sh, which are found in the $WMR_HOME/bin directory.

Because these scripts actually make use of Hadoop's startup scripts, they must be able to find the Hadoop installation. As a result, you must either put the main hadoop executable on the system $PATH (or equivalent), or set the environment variable $HADOOP_HOME.

To start the daemon, run the start-wmr.sh script (be sure to run it as the user you created previously):

$ cd $WMR_HOME
$ bin/start-wmr.sh
starting edu.stolaf.cs.wmrserver.EmbeddedServer, logging to
$HADOOP_HOME/logs/hadoop-user-edu.stolaf.cs.wmrserver.EmbeddedServer-hostname.out

If all goes well, the command should produced output similar to that shown above. Check the log file listed in the output for any errors.

At this point, WMRServer should be running succesfully. Until you have set up a frontend, however, it is not very useful. Go ahead and stop the daemon:

$ bin/stop-wmr.sh
stopping edu.stolaf.cs.wmrserver.EmbeddedServer