MPI Installation

[Chen_Li]

Two questions, first on the Cluster Studio installation.

In the document, software "expect" is needed to make the ssh connectivity between nodes of the cluster. However, in my current cluster, all my nodes can ssh to each other without password. I wonder whether I can skip this "expect" requirement, since I do not want to complicate the existing ssh environment.

Second question, on using Intel MPI

After I installed on each node, I can use mpirun to test run MPI code on one node without problem, I can also use mpirun within SGE script to run MPI job across nodes without problem. But if I try to run mpiexec on a node, I get errors below. Could anyone give a hint of what is wrong?  Thanks a lot! 

[compute-0-2 FD3DVer1.0]mpiexec -np 2 -host localhost ./fd3dmpiVer1Debug

mpiexec_compute-0-2.local: cannot connect to local mpd (/tmp/mpd2.console_lichen); possible causes:
1. no mpd is running on this host
2. an mpd is running but was started without a "console" (-n option)

[Chen_Li]

I get the answer to my second question, I need to start up a mpd on that node first. But if you have further suggestion on hydra I would appreciate.

[James_T_Intel]

Hi Chen, You will only need expect to run the sshconnectivity script. That script is provided to set up passwordless SSH. Since you already have this set up, you will not need it. Also, using mpiexec uses MPD as the process manager. We recommend using Hydra instead. If you use mpirun, it will default to Hydra. You can use the environment variable I_MPI_PROCESS_MANAGER=mpd to use MPD with mpirun, and it will automatically launch the MPD ring when run. You can also use mpiexec.hydra to explicitly use Hydra. Sincerely, James Tullos Technical Consulting Engineer Intel® Cluster Tools