Sorry all, Chris S over on the slurm list spotted it right away. I didn't have the MpiDefault set to pmix_v2.
I can confirm that Ubuntu 18.04, gcc-7.3, openmpi-3.1.0, pmix-2.1.1, and slurm-17.11.5 seem to work well together. Sorry for the bother. _______________________________________________ users mailing list users@lists.open-mpi.org https://lists.open-mpi.org/mailman/listinfo/users