> 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.
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.