Quickstart

Say you have access to a Slurm cluster with apptainer installed, and you have permission to submit to the batch partition.

Copy the hello.yaml file from the examples directory to your current working directory, then run:

slappt hello.yaml > job.sh

Alternatively, without the configuration file:

slappt --image docker://alpine \
       --shell sh \
       --partition batch \
       --entrypoint "echo 'hello world'" > hello.sh

Your hello.sh script should now contain:

#!/bin/bash
#SBATCH --job-name=0477f4b9-e119-4354-8384-f50d7a96adad
#SBATCH --output=slappt.0477f4b9-e119-4354-8384-f50d7a96adad.%j.out
#SBATCH --error=slappt.0477f4b9-e119-4354-8384-f50d7a96adad.%j.err
#SBATCH --partition=batch
#SBATCH -c 1
#SBATCH -N 1
#SBATCH --ntasks=1
#SBATCH --time=01:00:00
#SBATCH --mem=1GB
module load apptainer  # only if you need, some clusters
apptainer exec docker://alpine sh -c "echo 'hello world'"

If already on the cluster, use the --submit flag to submit the job directly. (Standard Slurm commands must be available for this to work.) In this case the job ID is shown if submission was successful.

You can provide authentication information to submit the script to remote clusters over SSH. For instance, assuming you have key authentication set up and your key is ~/.ssh/id_rsa:

slappt ... --host <cluster IP or FQDN> --username <username>

Caveats

There are a few things to note about the example above.

Shell

For most image definitions, specifying the shell is likely not necessary, as the default is bash. However, for images that don’t have bash installed (e.g., alphine only has sh) a different shell must be selected.

Singularity support

If your cluster still uses singularity, pass the --singularity flag (or set the singularity key in the configuration file to true) to substitute singularity for apptainer in the command wrapping your workflow entrypoint.

Pre-commands

Note: if apptainer or singularity are not available by default on your cluster’s compute nodes, you may need to add --pre commands (or a pre section to the configuration file), for instance --pre "module load apptainer", or:

pre:
  - module load apptainer