Starting an Interactive Session

Normally, compute nodes are only accessible to programs or jobs submitted as batch scripts to the scheduler. This mode of operation is ideal for well-understood research computing pipelines, but may need to be approached more piecemeal through interactive sessions on compute nodes. This page documents how to obtain interactive shell sessions on compute nodes. Note that interactive graphical sessions are available through the webapp.

Once logged in, to launch an interactive compute session, simply run the following command:

This will launch an interactive compute session on one of the conventional compute nodes (specifically granting one core for up to four hours within the htc partition).

Once the session launches, you can begin using the system through the terminal window.

X11 Forwarding is Automatic

If you need to run an X11-based program, launch an interactive session and run the program from within that terminal session.

This will automatically use the X11-forwarding feature built into your shell (in the case of Linux). On MacOS and Windows, using X11 apps natively on your workstation desktop may require an X11 client (such as Xquartz or Cygwin/X. The setup and use of these applications are beyond the scope of this document. Alternatively, you can therefore use the Research Computing supported clients X2Go and the webapp.

Interactive Session Options

The interactive command will work with many of the same options and switches as other slurm job-launching commands. This is because interactive is an sbatch job under the hood. Any option that would be passed within an sbatch script or to the sbatch command itself will be accepted by interactive and will override its defaults.

For example, you can specify how many cpu cores your want your interactive session to use with the -c number option.

You can also specify how long you would like your session to run with the -t days-hours:minutes option.

An example of using these options to launch an interactive session that uses 8 cpu cores on one node, runs for zero days and 4 hours