The CHPC hosts a heterogeneous supercomputer comprising:

• Westmere cluster (Sun & Dell) x86
• Nehalem cluster x86
• Harpertown cluster x86
• M9000 SMP (Sparc-64 V9)
• Nvidia Quadro FX5600 visualization node (G80 core)

All these systems are accessed via a single login node sun.chpc.ac.za.

Connections to the login nodes of the CHPC machines is via the ssh protocol. To connect to the SUN system use

  ssh username@sun.chpc.ac.za

where username is replaced by the user name assigned to your account at the CHPC.

The hostnames for all CHPC login nodes are listed below. If you are within CHPC the DNS server will return RFC 1918 addresses, if you are outside you will get globally routeable addresses.

Use scp or sftp to transfer files to or from your home directory on the CHPC systems. For example

  scp src.tar.gz username@sun.chpc.ac.za:~/scratch/

to copy the file src.tar.gz to your scratch directory on the SUN cluster.

The best way to connect via ssh is to create ssh keys which authenticate you instead of your password.

First create your private and public keys on your main work computer (which we assume is a desktop or laptop computer running Linux)

  ssh-keygen -t dsa

This creates two new files in your .ssh directory

It is the latter file that you need to add to the .ssh/authorized_keys file in your home directories on the CHPC login nodes (SUN or IBM Blue Gene).

From a recent Linux distribution you can simply do this :-

  ssh-copy-id username@sun.chpc.ac.za

From older Unix setups you might have to do this :-

  cat ~/.ssh/id_dsa.pub | ssh username@sun.chpc.ac.za "cat >> .ssh/authorized_keys; chmod 0700 .ssh; chmod 0600 .ssh/authorized_keys"

And the next time you ssh or scp to the CHPC login node you won't have to use your password!

(Notice that you need to change the permissions of the .ssh directory and the authorized_keys file on the login nodes to make them private and readable by you only before ssh will use the new public key.)

Cygwin provides all the above Linux commands for the Windows command line (and replaces the limited CMD.EXE command line).

For first-timers there is a nice introduction at lifehacker.

Should you prefer a MS Windows application with a GUI to connect to the CHPC we suggest you download and install the open source PuTTY and WinSCP clients:

It is strongly recommended that you use ssh keys to connect to the CHPC. To generate and configure putty-ssh to use keys please see:

• HowToForge tutorial
• Putty-ssh documentation