Containers allows you to package an application and its dependencies into a container image. This image contains everything needed to run the application, including libraries and environment variables.Containers are a convenient and efficient way to make your applications portable and reproducible.

Apptainer is the container platform available on Tempest. You do not need to load any modules to use Apptainer. The below documentation is pulled from Apptainer's documentation

For an overview of apptainer usage, run the following in the terminal:

apptainer --help

Pull an Image from Docker

As per your requirements, search the relevant docker image and use the following command to pull it. 

(In this example we are using a python image from docker)

apptainer pull docker://python

This will pull the .sif file into your home directory on Tempest.

Run Your Code in the Container

The execcommand allows you to execute a custom command within a container by specifying the image file.

Here I am using the python.sif (pulled in the previous step) and executing my custom python script in it.

apptainer exec python.sif python example.py

example.py is the name of my python file, present in the home directory on Tempest.

Since we are running python code in the container, there is no need to load the python module.

Run the Container in Slurm

In order to run the container in a slurm job, Here is an example:

#!/bin/bash

#SBATCH --partition=test                
#SBATCH --cpus-per-task=2
#SBATCH --mem=2G
#SBATCH --time=0-01:00:00
#SBATCH --job-name=container-example

# %x is the job name, and %j is the job number
#SBATCH --output=%x-%j.out
#SBATCH --error=%x-%j.err

echo "container test"
apptainer exec /home/<netID>/python.sif python /home/<netID>/pythonExample.py