Prerequisite: OpenSSH

See the page on generating keys.

Connecting to the VSC clusters

Text mode

In many cases, a text mode connection to one of the VSC clusters is sufficient. To make such a connection, the ssh command is used:

$ ssh <vsc-account>@<vsc-loginnode>

Here,

  • <vsc-account> is your VSC username that you have received by mail after your request was approved,
  • <vsc-loginnode> is the name of the loginnode of the VSC cluster you want to connect to.

You can find the names and ip-addresses of the loginnodes in the sections on the available hardware.

The first time you make a connection to the loginnode, you will be asked to verify the authenticity of the loginnode, e.g.,

$ ssh vsc98765@login.hpc.kuleuven.be
The authenticity of host 'login.hpc.kuleuven.be (134.58.8.192)' can't be established.
RSA key fingerprint is b7:66:42:23:5c:d9:43:e8:b8:48:6f:2c:70:de:02:eb.
Are you sure you want to continue connecting (yes/no)?

Here, user vsc98765 wants to make a connection to the ThinKing cluster at KU Leuven via the loginnode login.hpc.kuleuven.be.

If your private key is not stored in a default file (~/.ssh/id_rsa) you need to provide the path to it while making the connection:

$ ssh -i <path-to-your-private-key-file> <vsc-account>@<vsc-loginnode>

Connection with support for graphics

On most clusters, we support a number of programs that have a GUI mode or display graphics otherwise through the X system. To be able to display the output of such a program on the screen of your Linux machine, you need to tell ssh to forward X traffic from the cluster to your Linux desktop/laptop by specifying the -X option. There is also an option -x to disable such traffic, depending on the default options on your system as specified in /etc/ssh/ssh_config, or ~/.ssh/config.
Example:

ssh -X vsc123456@login.hpc.kuleuven.be

To test the connection, you can try to start a simple X program on the login nodes, e.g., xterm or xeyes. The latter will open a new window with a pair of eyes. The pupils of these eyes should follow your mouse pointer around. Close the program by typing "ctrl+c": the window should disappear.

If you get the error 'DISPLAY is not set', you did not correctly enable the X-Forwarding.

Links

Cleint