[tutorial] Run a GitLab Runner that submits SLURM jobs on Baobab

Hi Yann,

Thanks a lot for the great tutorial.

Some of my CI jobs need to build container images on compute nodes using buildah inside Apptainer with --fakeroot. Currently Apptainer falls back to a root-mapped namespace because my user has no subuid/subgid entries:

INFO: User not listed in /etc/subuid, trying root-mapped namespace

This causes lchown failures during image layer extraction since only UID/GID 0 is mapped:

lchown /etc/gshadow: invalid argument (requested 0:42)

Request: Can you please add subuid/subgid entries for my user or all users on login and compute nodes?

# /etc/subuid and /etc/subgid

username:100000:65536

I saw you had already done something similar in Feb 2022 on login2.baobab (see forum thread about podman subuid errors: https://hpc-community.unige.ch/t/solved-cannot-login-to-login2/260).

Thanks!

Maroun