Apptainer

SCRP compute nodes have Apptainer 1.2.5 installed.

Basics

Apptainer allows user to run a contained environment potentially different from the host. You can run programs not installed on SCRP or even run a completely different version of Linux.

To use Apptainer you need a Apptainer image that suits your needs. You can build one from scratch, but it is typically much more convenient to use existing images built by others. You can find images on Singularity Library. Docker containers can also be converted to use with Apptainer.

To run a Apptainer image for interactive use, type:

compute apptainer shell image_path

Note that image_path can be a URL, in which case the image will first be downloaded.

If you need GPU, type instead:

gpu apptainer shell --nv image_path

For batch execution, use apptainer exec instead of apptainer shell.

Both compute and gpu allocate four logical CPUs on a compute node, with the addition of a GPU for the latter. Use srun or sbatch if you need more control over resource allocation.