Document how to use singularity

[lesteve]

From https://gitter.im/jean-zay-users/jean-zay-doc?at=5eda173d225dc25f54c99d35 except now that nodes are RedHat8 so it is a bit simpler

Build singularity image on the login node:

export SINGULARITY_CACHEDIR=$SCRATCH/cache-singularity/
export PATH=/gpfslocalsys/singularity/singularity-3.5.2-s-rhel8/bin:$PATH\n\n
# build singularity image from pytorch/pytorch docker image on DockerHub
singularity build $WORK/pytorch.simg docker://pytorch/pytorch:latest

Start an interactive job for testing

(you could use singularity the same way in a job submission script)

srun --pty --ntasks=1 --cpus-per-task=10 --gres=gpu:1 --hint=nomultithread --partition=gpu_p1 bash

Use the singularity image inside a job

Inside the compute node (i.e. after your interactive job has started)

export SINGULARITY_CACHEDIR=$SCRATCH/cache-singularity/
export PATH=/gpfslocalsys/singularity/singularity-3.5.2-s-rhel8/bin:$PATH\n\n
singularity exec --nv $WORK/pytorch.simg python -c 'import torch; print(torch.__version__)'

[lesteve]

So it seems that Jean Zay user support has found a problem with singularity so singularity will not available for for a few weeks until they fix the problem.

[mdiazmel]

This feature is supposed to be release before dec20!
Building image and sandbox won't be allowed. There will be some kind of tool to check safety/integrity of the uploaded images. Looking forward for a nice documentation...

[RemiLacroix-IDRIS]

Looking forward for a nice documentation...

Very soon!

[lesteve]

🤞

[RemiLacroix-IDRIS]

I just had the confirmation that everything should be available today (the Singularity module, the idrcontmgr command and the documentation).

[RemiLacroix-IDRIS]

The documentation is here: http://www.idris.fr/eng/jean-zay/cpu/jean-zay-utilisation-singularity-eng.html, the module and idrcontmgr command are available as well.

[lesteve]

Great news, thanks a lot!