srun: MPI types are...
srun: none
srun: openmpi
srun: pmix_v3
srun: pmi2
srun: pmix
but I'm not sure that tells me much about how I am supposed to be
building OpenMPI?
On 3/27/23 14:41, Pritchard Jr., Howard wrote:
HI Craig,
If you run
srun –mpi=list
what does slurm report?
That will help in determining what argument you want to supply for the
–mpi srun option.
Howard
*From: *slurm-users <slurm-users-boun...@lists.schedmd.com> on behalf
of Craig <cfre...@super.org>
*Reply-To: *Slurm User Community List <slurm-users@lists.schedmd.com>
*Date: *Monday, March 27, 2023 at 12:38 PM
*To: *"slurm-users@lists.schedmd.com" <slurm-users@lists.schedmd.com>
*Subject: *[EXTERNAL] [slurm-users] OpenMPI and Slurm clarification?
Can someone please clarify the "best practices" for building OpenMPI
compatible with Slurm?
https://slurm.schedmd.com/mpi_guide.html#open_mpi
<https://urldefense.com/v3/__https:/slurm.schedmd.com/mpi_guide.html*open_mpi__;Iw!!Bt8fGhp8LhKGRg!Cb86a2IwxgqfT5fv1_eEByDpAyhly3ZdN6Wwl7Wod9FRPx9HBpvFVojIRgu5oSpti_3jOXhNyvJqEMGs$>
tells me what I _can_ do but I'm unclear as to what I _should_ do.
I've built OpenMPI 4.1.5 with: --with-pmix --with-libevent=internal
--with-hwloc=internal --with-slurm. If I run an MPI program on my
cluster (slurm 18.08.8) with "srun -N2 foo" it seems to work fine.
(slurm.conf has MpiDefault=pmix).
If I "srun --mpi=openmpi -N2 foo" it chokes with:
OPAL_ERROR: Unreachable in file
../../../../../opal/mca/pmix/pmix3/pmix3x_client.c at line 112
-------------------------------------------------------------------------------------------------------------------
This application appears to have been direct launched using "srun",
but OMPI was not build with SLURM's PMI support and therefore cannot
execute. There are several options for building PMI support under
SLURM, depending upon the SLURM version you are using:
version 16.05 or later: you can use SLURM's PMIx support. THis
require that you configure and uild SLURM --with-pmix.
.
.
.
So I guess the question is, what is the "right" way to build OpenMPI
with Slurm. Is the fact that my non-Slurm pmix works "correct" or am
I just getting lucky that the various software I have just happens to
be compatible. If I build OpenMPI am I supposed to use Slurm's
pmix/libevent/hwloc or is that optional. If it's optional when/why
might I choose to do so. If I need Slurm's versions is there some way
to find which pmix/libevent/hwloc my current Slurm install is using?
Note: my sysadmins are not going to be helpful as they think Slurm 18
and OpenMPI 4.0.2a is adequate for users' needs :^(.
I like the idea of _not_ tying my OpenMPI to the installed Slurm just
in case our support people ever decide to upgrade system software.
Thanks.
