A cluster is not a laptop with extra cores. The software you can see is a set of blessed combinations, and the modulefile is the contract for one of them.
Load a stack, not a souvenir#
module load gcc openmpi cuda from three different generations is how you get a binary that links and a job that dies in MPI_Init. Load the site's metapackage, or a versioned toolchain the handbook names. Then stop.module purge is not optional#
Login profiles accumulate. Yesterday's PETSc is still in
LD_LIBRARY_PATH when today's GROMACS starts. Purge, then load, in the job script, every time.Record what you loaded#
module list in the job log is cheaper than reconstructing a toolchain from memory six months later, after the default GCC has moved. If the site offers spack or EasyBuild generated modules, pin the hash or the version, not "the default".What not to do#
Do not
export PATH=$HOME/local/bin:$PATH and then file a ticket that "MPI is broken". Your overlay is now the software stack. The helpdesk cannot see it.