EEC High Performance Computing

This guide describes how to submit StarCCM+ job on ZEUS HPC, connect to the StarCCM+ server form your local Windows installation of StarCCM+.

1. Assuming you have StarCCM+ installed on your Windows PC, say I have “STAR-CCM+ 8.04.007-R8 for Windows 64” installed from ld-fs-01ECSoftwareStudent (network share)
2. Assuming you have full installation of SSH-client PuTTY installed on your Windows PC, “full” means you have not just “putty.exe” executable, but also “plink.exe” and “puttygen.exe” for connection in command line and generating rsa-key for pasword-less connection to the cluster.  If you don’t have full install of PuTTY: http://the.earth.li/~sgtatham/putty/latest/x86/putty-0.63-installer.exe
3. First Let’s create ssh-keys for Putty (this step is not compulsory, if you don’t do it you can still enter passwords when connecting in steps 7-8:  (a) Launch PuTTYgen (b) Generate key (c) save public and private key, say in your home folder “c:Usersag7634sshpublic.pub”, “c:Usersag7634sshprivate.ppk”. Copy “OpenSSH key string from the top of PuttyGen windows” and insert it into “authorized_keys” file on ZEUS in your home folder “/home/ag7634/.ssh/authorized_keys”. See, eg. see here procedure in more details. Or just Google for “paswordless putty connection”.
4. Now we are ready to submit Starccm+ job on HPC:
   • Transfer your simulation files to your zeus’s home folder, say I copied my test *.sim file into “~/test/casesim.sim” on zeus (where ~/ stands for your home folder, i.e. /home/ag7634). I use WinSCP for copying files to/from HPC. Another possibility to copy files is discussed here.
   • Login to HPC with Putty (hopefully now you can login without entering password, with the key –see step 3)
   • In Putty console window change to your working folder, say I do “cd test” to get to my sim file.
   • If you havent’ set up yet job submission script on ZEUS, use the template from here:  /share/slurm_scripts/starccm_submit.slurm, i.e to copy it to your working folder do: “cp /share/slurm_scripts/starccm_submit.slurm  ./”
   • Change details in this slurm submission script — open it in text editor (or edit it from WinSCP session). Save it.
   • load the starccm+ module of needed version, i.e. I do: “module load starccm/8.04.007”. To list of all available modules do “module avail”.
   • Submit the job — from your working folder do:  “sbatch starccm_submit.slurm”
   • This will start starccm+ server process on one of the compute nodes. List of all nodes you reserved is in “hostfile.txt” in your working folder. Normally starccm+ server process run on the 1st node in the list on port 47827.
5. Now we have to connect to this starccm+ server process in order to start iterations or pre-post processing. For this we have to connect to the target node, on which starccm+ server process is running form your local PC starccm+ installation.
6. Say, the first node in “hostfile.txt” list of reserved nodes is zeus81. So there is a good chance that server process is running on this node.
7. To establish the tunnel to this node form your Desktop PC we create small script file on youe Windows PC. Open notepad and put there (change the path to plink.exe if yours is different):
   start \coventry.ac.ukCSVStudentsSharedECSTUDENTHPCputtyplink.exe -ssh -2 -l %USERNAME% -noagent -i  %USERPROFILE%sshprivate.ppk -N -L 47827:$1:47827 zeus
   You can skip “-i %USERPROFILE%sshprivate.ppk ” part if did not bother to set up ssh-key and password-less connection as described above.

   Note that there is a link to plink.exe from PuTTY installation on your PC, check if the file there or if not adjust the path to it.

   There is also the path to private ssh-key file we generated with puttygen.exe previously in step 3.

   %USERPROFILE% will point windows to your home folder, e.g. c:Usersag7634. …. “c:Usersag7634sshprivate.ppk” is where private key file was saved.

   Change also “ag7634” to your username on HPC.

   Save this text file as, say “tunnel.cmd” in location “visible” by Windows.

   I tend to store such files in my home folder in “bin” directory (create if needed), i.e. in “C:Usersag7342bin”.  To make “bin” visible from any location I added it to the PATH variable: “right-click on My Computer->Properties-Advanced system settings->Environment Variables->New USER VARIABLE-> name: PATH, value: %USERPROFILE%bin

8. The result that we want after saving “tunnel.cmd” is such: press WinKey+R (or Run from start menu), type there
   

   tunnel zeus81

   and hit Enter. This will open command window with tunnel to zeus81 node.
   

   Leave this window running! This is your tunnel to the node!

9. Now start StarCCM+ on your Desktop PC. Menu: File->Connect to Server. Host: localhost   port: 47827 (default). DO NOT CHECK “connect through SSH tunnel”. DO NOT CLICK “Scan Host”. These options will not work. Just click OK. You now must see your sim-filename in the list of starccm+ servers on the left, which you can click and do whatever you intended to do. This Starccm session is running on your Desktop Windows PC, which processes are being executed on Zeus HPC.
10. If you just close this StarCCM+ session with “x”, it may terminate server process. So to disconnect (say you launched iterations and now need to wait 30 hours) do menu->”File: Disconnect” first and then close StarCCM+ window.
11. Later you may connect again to the same StarCCM+ server to check progress or whatever. You can close putty tunnel command window, it will terminate the tunnel. But later you can again do step 8: i.e. launch the tunnel to the same node, and open StarCCM+ local session.
12. Don’t forget to terminate the job on HPC (your starccm+ server process in the queue if you finished.

Alex.