10.2. Prerequisites

In general, successful launch of Open MPI jobs requires the ability to find Open MPI’s executables and shared libraries on all nodes at run time. If these can be via in system-default search paths (e.g., without the user needing to set or modify PATH or LD_LIBRARY_PATH), nothing additional needs to be done. For example:

  • If Open MPI is installed in /usr/bin and /usr/lib), that is usually sufficient, and the user does not need to do anything extra.

  • If Open MPI is installed in a location that is not searched by default, users may need to add $prefix/bin to their PATH and $libdir (which defaults to $prefix/lib) to their LD_LIBRARY_PATH.


    In scheduled environments, ensuring Open MPI’s executables and libraries can be found on the node that executes mpirun(1) may be sufficient.

    In non-scheduled environments, users may need to set the PATH and LD_LIBRARY_PATH environment variables in their shell setup files (e.g., $HOME/.bashrc) so that non-interactive ssh-based logins will be able to find the Open MPI executables and libraries.

If users are unable to add the relevant directories to PATH and LD_LIBRARY_PATH,the mpirun(1) --prefix option may be sufficient.