4.1. SSH

Bohrg and Dominion can be accessed only by SSH and related utilities (SCP and SFTP). Furthermore, to increase security SSH on your desktop machine needs to be configured to use a DSA key with a passphrase.

4.2. Using X-Windows

The X Window System can be used to display windows which are "launched" from Bohrg on your local desktop, but such connections must be tunnelled through the original SSH connection.

At the time of writing (2005 Apr 14) tunnelling has not been set up on Dominion.

4.3. Gateway Machines

The Bohrg and Dominion clusters are protected by gateway machines, called bohrg1.man.ac.uk and bohrg3.man.ac.uk, respectively. In practice this means that:

• you must login to either bohrg1 (for Bohrg) or bohrg3 (for Dominion) and from there login to the (head/submit) node of the cluster itself, rather than accessing the clusters directly;
  
  
• setup a SSH DSA key-pair with passphrase before you can use either cluster.

4.4. Head/Submit Nodes

Behind the gateway machines, each cluster consists of a "head" or "submit" node and a number of "compute" nodes. Jobs are submitted to the batch-queueing system (SGE) from the head/submit nodes; jobs run on the compute nodes. (There is no reason for users to login to the compute nodes.)

Bohrg

The head node for this cluster is called storage. (This node doubles as the machine on which the SCSI disk array resides.)

Dominion

The head node for this cluster is called dominion1.