Bug#1120695: openmpi-bin: Unable to find reachable pairing between local and remote interfaces

[Santiago Vila]

On Fri, Nov 14, 2025 at 09:50:29PM +0100, J.L.G. Pallero wrote:
> Package: openmpi-bin
> Version: 5.0.9-1
> Severity: important
> X-Debbugs-Cc: jgpallero at gmail.com
> 
> Dear Maintainer,
> 
> Trying to execute a MPI program with mpirun that works a few days ago, it still works, but I obtain some strange messages I can't interpret. The messages are:
> 
> [geo-w540][[64946,1],2][../../../../../../opal/mca/btl/tcp/btl_tcp_proc.c:266:mca_btl_tcp_proc_create_interface_graph] [geo-w540][[64946,1],1][../../../../../../opal/mca/btl/tcp/btl_tcp_proc.c:266:mca_btl_tcp_proc_create_interface_graph] Unable to find reachable pairing between local and remote interfaces

Hello. I had a similar problem some time ago, which I forwarded here:

https://github.com/hypre-space/hypre/issues/1194

Can you try this to see if the messages (which afaik are just warnings
and harmless) go away?

export OMPI_MCA_btl_tcp_if_include=lo 

Thanks.