basically you just need to follow how to launch a job on multiple IPs in MPI.
here is a good tutorial to do that: http://mpitutorial.com/tutorials/running-an-mpi-cluster-within-a-lan/ 94
, which basically tells you that you need to prepare a hostfile with private addresses of all nodes in your cluster. Then when you launch your job from the master node, you need to provide appropriate dir of the hostfile
Hope this helps