This plugin makes Jenkins cluster act as a Hadoop cluster without any configuration.
When you install this plugin, Jenkins will start a Hadoop "master" (namenode and job tracker, in their jargons) on the Jenkins master. On each slave that Jenkins starts, this plugin also starts a Hadoop "slave" (datanode and task tracker, in their jargons.) Hudson then instructs Hadoop to form a cluster among those nodes. All the jar files needed to run Hadoop is packaged inside this plugin, and will be automatically deployed to eveyrwhere they are needed.
In this way, this plugin takes your machines in your Jenkins cluster and runs a Hadoop cluster very easily.
Once installed, you'll see the "Hadoop" link in the Jenkins top page.
This link will take you to the information page that shows links to Hadoop web UI, as well as the configuration users need on their
Slave log page (
http://yourserver/hudson/computer/SLAVENAME/log) will also include text showing how the hadoop slave JVM is launched. Any error encountered will be recorded there, too.
Once you run this, you'll get $HUDSON_HOME/hadoop/dist directory that contains the stripped down version of Hadoop. You can change conf/hadoop-site.xml in this directory to apply different parameters.