Interactive jobs

For compute-intensive tasks that require real-time user interaction—such as working with MATLAB, debugging code, or running Gaussian calculations—you should not run them on the login nodes. Login nodes are for light work like editing files and submitting jobs.

Instead, you must request an interactive session on a compute node. There are two main ways to do this.

Portal interactive apps

Our Web Portal provides a number of interactive apps including popular IDEs such as Jupyter, RStudio, and CodeServer. Additionally, the Interactive Desktop provides a full graphical user interface similar to a remote desktop where you can launch software with graphical components and manage files interactively.

See our Portal documentation for more information

Command line interactive sessions

The salloc command does this by first finding and allocating the resources you request, and then giving you a new command prompt directly on that compute node.

You can then run all your intensive commands in that new shell for the duration of the allocation. 

salloc --nodes=1 --ntasks=4 --mem=16G --account=<account> --time=01:00:00

salloc is a Slurm command, which takes many options. In the above example, --nodes or -N is the number of nodes, --ntasks or -n the number of cores, and --time or -t the run time.

Option -A or --account <account> specifies your paid credit account or allocation;

To request an interactive job with a GPU, under a credit account use

salloc --account=<credit_account> --partition=standard --ntasks=4 --mem=32G --time=01:00:00 --gres=gpu:a100:1

Under a paid allocation (that includes GPU nodes), use 

salloc --account=<your_allocation> --partition=sla-prio --ntasks=4 --mem=32G --time=01:00:00 --gres=gpu:a100:1

For more details, see Resource requests.

Firefox

With Firefox, you can access OneDrive and other such sites, and upload and download files.
From the Portal Interactive Desktop, select Web Browser from the Applications menu.

Firefox is also available via ssh -X, after loading its module with module load firefox.
From the command line, execute firefox.

Users may need to set the default browser manually using either:

  • in their .bashrc file: 

    BROWSER=/storage/icds/tools/sw/firefox/firefox

  • In an Interactive Desktop session, Applications > Settings > Settings Manager, then select Default Applications. Under the Internet tab, there is a field for Web Browser. Firefox is located at /storage/icds/tools/sw/firefox/firefox

Using Firefox in Interactive Desktops

When using Firefox within an Interactive Desktop session, the operating system may ask for a path when you attempt to save or upload files. You can navigate to your storage directories using paths like /storage/home/<username> or /storage/work/<username>.

VirtualGL

For applications that produce graphical output (plots, figures, graphical user interfaces, and so on), using OpenGL can speed up the drawing.

For this to work, you must either use the Portal, or log on with X forwarding and run an interactive job on a GPU node. Then, you can launch your application with 

vglrun <application>

Example : 
module load matlab
vglrun matlab