Interactive Access to the Compute Nodes

Interactive Batch

Interactive access to the compute nodes is possible with the so-called "interactive batch". An interactive batch session is opened by the qsub -I command provided that the resources are available. Example:

qsub -I -l nodes=1,walltime=1:30:00

If a free compute node is available, this examle opens an interactive batch on one node with a duration of one and a half hours. You can request up to 16 nodes for a maximum of 8 h. The batch system PBS needs about half a minute to establish the interactive batch session. When the command prompt appears, you can type in Linux commands like in an interactive session.

To work with graphical windows use the -X option additionally. Example:

qsub -I -X -l nodes=1,walltime=1:30:00

Note that your SSH connection to the login server must be X11 capable, too. You can close an interactive batch session with <Ctrl>D or with the exit command.

Interactive Access via SSH

Interactive access to compute nodes via SSH is only possible during an interactive batch session or at the runtime of a batch job and only to compute nodes which the batch system allocated to the user after sending the qsub command.