Hi, I'm having some issues to make mpirun/mpiexec play nicely with Slurm allocations. I'm using Slurm 19.05.4, and have configured MPICH with: --enable-shared --enable-static --with-slurm=/sw/slurm/19.05.4 \ --with-pm=hydra Now I request resources from Slurm with: $ salloc -N 2 --ntasks-per-node 4 Then when I try to run a test binary: $ mpiexec.hydra ./mpich_hello Error: node list format not recognized. Try using '-hosts=<hostnames>'. Aborted (core dumped) When I do the same with OpenMPI's mpirun/mpiexec it runs on the allocated nodes. Am I missing something, or does MPICH simply not support this use case? Currently I'm working around this by using a script to translate Slurm node allocations into a host list and run like this: $ mpiexec.hydra -hosts $(mpich-host) ./mpich_hello That works fine, but I suppose this workaround should not be necessary. Here is ltrace output which shows that mpiexec tries to process some Slurm related environment variables but apparently fails to do so: https://paste.ubuntu.com/p/327tGrTzq5/ I've also tried with salloc -N 1 -n 1, so that the environment variables are simpler, e.g. SLURM_NODELIST=node-b01 SLURM_TASKS_PER_NODE=1 but that did not change the way mpiexec fails. /Stefan