[BUG] s6-applyuidgid fails when using podman's -u flag

[billy4479]

Is there an existing issue for this?

• I have searched the existing issues

Current Behavior

The container starts and recognizes that it is running as a non-root user (in my case UID=5000, GID=5000) however the log gets spammed with

s6-applyuidgid: fatal: unable to set supplementary group list: Operation not permitted

Expected Behavior

No response

Steps To Reproduce

I'd like to have an user dedicated to running containers. In my case it is called containers and has uid=5000.

I am running the container with

podman  \
  run \
  --name=syncthing \
  --log-driver=journald \
  --cidfile=/run/syncthing/ctr-id \
  --cgroups=enabled \
  --sdnotify=conmon \
  -d \
  --replace \
  -e TZ=Europe/Rome \
  -e PGID=5000 \
  -e PUID=5000 \
  -p 8384:8384 \
  -p 22000:22000/tcp \
  -p 22000:22000/udp \
  -p 21027:21027/udp \
  -u containers:containers \
  -v /mnt/a-disk/config:/config \
  -v /mnt/a-disk/data:data \
  --rm \
  --pull missing \
  '--ip=10.0.1.2' \
  lscr.io/linuxserver/syncthing:latest

(note that this command is generated by Nix).

Running with or without -e PGID=5000 -e PUID=5000 makes no difference (as described by the wiki).

Edit: Fix typo UID -> PUID, still get the same result

Environment

- OS: NixOS unstable
- How docker service was installed: it's podman, nix package manager

CPU architecture

x86-64

Docker creation

see how to reproduce.

Container logs

/package/admin/s6-overlay/libexec/preinit: info: /run belongs to uid 0 instead of 5000 - fixing it
╔═════════════════════════════════════════════════════════════════════════╗
║                                                                         ║
║           You are running this container as a non-root user:            ║
║   UMASK, custom services, & docker mod functionality will be disabled   ║
║      and the PUID/PGID environment variables will have no effect.       ║
║                                                                         ║
╚═════════════════════════════════════════════════════════════════════════╝
[migrations] started
[migrations] no migrations found
───────────────────────────────────────

      ██╗     ███████╗██╗ ██████╗
      ██║     ██╔════╝██║██╔═══██╗
      ██║     ███████╗██║██║   ██║
      ██║     ╚════██║██║██║   ██║
      ███████╗███████║██║╚██████╔╝
      ╚══════╝╚══════╝╚═╝ ╚═════╝

   Brought to you by linuxserver.io
───────────────────────────────────────

To support LSIO projects visit:
https://www.linuxserver.io/donate/

───────────────────────────────────────
GID/UID
───────────────────────────────────────

User UID:    5000
User GID:    5000
───────────────────────────────────────
Linuxserver.io version: v1.29.5-ls180
Build-date: 2025-04-12T13:15:21+00:00
───────────────────────────────────────

[custom-init] No custom files found, skipping...
s6-applyuidgid: fatal: unable to set supplementary group list: Operation not permitted
s6-applyuidgid: fatal: unable to set supplementary group list: Operation not permitted
s6-applyuidgid: fatal: unable to set supplementary group list: Operation not permitted
s6-applyuidgid: fatal: unable to set supplementary group list: Operation not permitted
s6-applyuidgid: fatal: unable to set supplementary group list: Operation not permitted
s6-applyuidgid: fatal: unable to set supplementary group list: Operation not permitted
s6-applyuidgid: fatal: unable to set supplementary group list: Operation not permitted
...

[github-actions]

Thanks for opening your first issue here! Be sure to follow the relevant issue templates, or risk having this issue marked as invalid.

[billy4479]

Sorry, I just noted that it is marked as a Reasonable Endeavour in the documentation, I'll work around it.

By removing the -u flag and leaving just -e PGID=5000 -e PUID=5000 I obtain a similar result (even if all the s6 processes still run as root).

I'll leave this open (but maintainers can feel free to close if they choose so) in case somebody has a solution.

Thanks!

[aptalca]

UID and GID are not valid env vars for our images

Also see https://docs.linuxserver.io/misc/non-root/

[billy4479]

UID and GID are not valid env vars for our images

Sorry, that was a typo

[LinuxServer-CI]

This issue has been automatically marked as stale because it has not had recent activity. This might be due to missing feedback from OP. It will be closed if no further activity occurs. Thank you for your contributions.