Have hard time to spawn process on two nodes in Slurm system

[YuxinxinChen]

Thank you for taking the time to submit an issue!

Background information

I am trying to run a simple hello-world mpi program on a slurm system

What version of Open MPI are you using? (e.g., v1.10.3, v2.1.0, git branch name and hash, etc.)

openmpi-4.0.1

Describe how Open MPI was installed (e.g., from a source/distribution tarball, from a git clone, from an operating system distribution package, etc.)

unzip the tar.gz file I install with default configure file and then make all install Follow this: https://www.open-mpi.org/faq/?category=building

Please describe the system on which you are running

• Operating system/version: CentOS Linux 7
• Computer hardware: Intel CPU
• Network type: Infiniband mlx5_0

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Details of the problem

I compiled the hello word code mpic++. I would like to run 2 processes on 2 nodes, each on one node. I salloc two nodes and login in the bash of one of them and run

mpirun --mca btl_openib_allow_ib 1 -np 2  mpi-send -host ivb113,ivb114

However, it doesn't run on two nodes but runs two processes on one node. If I run

mpirun --mca btl_openib_allow_ib 1 -np 2  -pernode mpi-send -host ivb113,ivb114

It returns error: Your job has requested more processes than the ppr for this topology can support:

App: mpi-send Number of procs: 2 PPR: 1:node

Please revise the conflict and try again.

This is confusing. Thanks for your help in advance

[ggouaillardet]

Can you please post your salloc command line?

[github-actions[bot]]

It looks like this issue is expecting a response, but hasn't gotten one yet. If there are no responses in the next 2 weeks, we'll assume that the issue has been abandoned and will close it.

[github-actions[bot]]

Per the above comment, it has been a month with no reply on this issue. It looks like this issue has been abandoned.

I'm going to close this issue. If I'm wrong and this issue is not abandoned, please feel free to re-open it. Thank you!