Cannot add user to the render system group

[MidnessX]

I'm trying to add a user to the render group as it should have access to a graphics card passed through by the host.

However, this has proven to be impossible as writing

[...]
passwd:
  users:
    - name: myuser
      groups:
        - render
[...]

results in ignition-files.service failing due to the render group missing, and manually creating the group by doing

[...]
passwd:
  groups:
    - name: render
      system: true
  users:
    - name: myuser
      groups:
        - render
[...]

instead results in ignition-files.service failing due to the render group already existing.

[bgilbert]

Thanks for the report. This is coreos/fedora-coreos-tracker#155. The issue is that usermod doesn't know to copy the render group from /usr/lib/group to /etc/group before trying to add a user to it. At the moment I believe you'd need to write a ConditionFirstBoot=true systemd unit which does something like grep ^render: /usr/lib/group >> /etc/group && usermod -G render -a core.

Closing as duplicate of coreos/fedora-coreos-tracker#155.