
New versions of OpenMPI need `--allow-run-as-root` for running as root: http://www.open-mpi.de/doc/v2.0/man1/mpirun.1.php#toc22
New versions of OpenMPI need `--allow-run-as-root` for running as root: http://www.open-mpi.de/doc/v2.0/man1/mpirun.1.php#toc22