I would recommend you to follow https://github.com/RevolutionAnalytics/rhadoop/wiki/Installing-RHadoop-on-RHEL to install RHadoop .
One more important thing is to go through the description file and install all the dependencies mentioned over there.
Package - Where to Install
plyrmr - On every node in the cluster
ravro - Only on the node that runs the R client
rhbase - Only on the node that runs the R client
rhdfs - Only on the node that runs the R client
rmr2 - On every node in the cluster
1. Download rmr2 from here.
2. Download the R packages dependencies for rmr2. Check the DESCRIPTION file for the most up-to-date list of dependencies.
3. Install rmr2 and its dependent R packages.
4. Update the environment variables needed by rmr2.
This is common step for installing all the r package.