# 10.8. Launching with LSF

Open MPI supports the LSF resource manager.

## 10.8.1. Verify LSF support

The `prte_info` command can be used to determine whether or not an installed Open MPI includes LSF support:

    shell$ prte_info | grep lsf

If the Open MPI installation includes support for LSF, you should see a line similar to that below. Note the MCA version information varies depending on which version of Open MPI is installed.

    MCA ras: lsf (MCA v2.1.0, API v2.0.0, Component v3.0.0)

Note

PRRTE is the software layer that provides run-time environment support to Open MPI. Open MPI typically hides most PMIx and PRRTE details from the end user, but this is one place that Open MPI is unable to hide the fact that PRRTE provides this functionality, not Open MPI. Hence, users need to use the `prte_info` command to check for LSF support (not `ompi_info`).

## 10.8.2. Launching

When properly configured, Open MPI obtains both the list of hosts and how many processes to start on each host from LSF directly. Hence, it is unnecessary to specify the `--hostfile`, `--host`, or `-n` options to `mpirun`. Open MPI will use LSF-native mechanisms to launch and kill processes (`ssh` is not required).

For example:

    # Allocate a job using 4 nodes with 2 processors per node and run the job on the nodes allocated by LSF
    shell$ bsub -n 8 -R "span[ptile=2]" "mpirun mpi-hello-world"

This will run the MPI processes on the nodes that were allocated by LSF. Or, if submitting a script:

    shell$ cat my_script.sh
    #!/bin/sh
    mpirun mpi-hello-world
    shell$ bsub -n 8 -R "span[ptile=2]" < my_script.sh