Try some simple tests:

- Does "tping -c 3" run successfully? (It should ping all the lamd's)

[ter@uftoscar test]$ tping -c 3 n0-13
1 byte from 13 remote nodes and 1 local node: 0.006 secs
1 byte from 13 remote nodes and 1 local node: 0.005 secs
1 byte from 13 remote nodes and 1 local node: 0.005 secs

3 messages, 3 bytes (0.003K), 0.016 secs (0.368K/sec)
roundtrip min/avg/max: 0.005/0.005/0.006

- Does "lamexec N hostname" run successfully? (It should run
"hostname" on all the booted nodes)

No, it doesn't work. It only show headnode's hostname. See below:

[ter@uftoscar ~]$ lamexec N hostname
uftoscar.latech
<freeze>

I, however, can execute "cexec hostname" with no problem.

- When you "mpirun -np 15 ring.out", do you see ring.out executing on

all the nodes? (i.e., if you ssh into each of the nodes and run ps,

do you see it running?

I only see one ring.out run on headnode, no ring.out running on other nodes.

Thanks
Kulathep