En el nodo maestro:

    apt-get update
    adduser mpiuser --uid 999
    apt-get install openmpi-bin openmpi-common libopenmpi1.6 libopenmpi-dev
    apt-get install nfs-kernel-server
    apt-get install nfs-common
    echo "/home/mpiuser *(rw,sync,no_subtree_check)" > /etc/exports
    service nfs-kernel-server restart
    exportfs -a

en demás nodos:
    apt-get update
    adduser mpiuser --uid 999
    apt-get install nfs-common
    mount -t nfs ip_del_master:/home/mpiuser /home/mpiuser/
    apt-get install openmpi-bin openmpi-common libopenmpi1.6 libopenmpi-dev

En maestro: 
    ssh-keygen  (enter enter enter...)
    copiar claves id_rsa.pub a .ssh/authorized_keys de cada nodo
    
    nano /home/mpiuser/mpi_hosts
   
    copiar este texto en archivo hosts en maestro:
--------------------------------------------------------------------------------
# The Hostfile for Open MPI

# The master node, 'slots=2' is used because it is a dual-processor machine.
localhost slots=2

# The following slave nodes are single processor machines:
cluster-nodo1
cluster-nodo2
--------------------------------------------------------------------------------

Para correr el programa:
mpirun -np 4 --hostfile mpi-hosts ./mpi_test