I think I fixed the problem. I at least have mpirun ... hostname
working over the cluster.
The first thing I needed to do was to make the gigabit network an
internal zone in Yast ... firewall (which essentially turns off the
firewall over this interface).
Next I needed to add the -mca options as follows:
mpirun --prefix /opt/openmpi -mca oob_tcp_include eth0 -mca
btl_tcp_if_include eth0 --hostfile ~/work/openmpi_hostfile -np 4
The above command works properly without the --prefix option,
verifying that my PATH and LD_LIBRARY_PATH variables are properly set
Unfortunately, I have jobs running on each machine in SMP mode that
will take the better part of this coming week to complete, so it will
be awhile before I will be able to do more than just mpirun ...
Could a section be added to the FAQ mentioning that the firewall
service should be shutdown over the mpi interface and that the two
-mca switches should be used? This could perhaps be most useful to a
beginner in either the 'Running MPI Jobs' or 'Troubleshooting'
sections of the FAQ.