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Subject: Re: [OMPI users] Communications problems w/OpenMPI
From: Jeroen Kleijer (jeroen.kleijer_at_[hidden])
Date: 2008-12-18 04:26:34


Hi,

> After compiling it, I copied it over to the other machine and tried
> running it with:
>
> mpirun -v --mca btl self,tcp -np 4 --machinefile machines /mnt/mpihw
>
> which produces:

[.....]

> AFAIK, the machines are able to communicate with each other on any port
> you like, just not with MPI. Any idea what's wrong?

The stable branch (1.2.x) works perfectly but _only_ when the
communication channel between machines are in the same subnet.
(ethernet)
Since you don't have that much control over which subnet your machines
get in, OpenMPI has a tendency to fail in Amazon's EC2.

However, if you're able to compile and use a version of the
development branch (1.3) you should be use compile and run the "hello
world" program without problems, regardless of the subnet they're in.

Regards,

Jeroen Kleijer