[cfarm-users] cfarm109 GPU access problem

[Baptiste Jonglez]

On 12-03-26, Zach van Rijn via cfarm-users wrote:
> On Wed, 2026-03-11 at 23:26 -0500, Jacob Bachmeyer wrote:
> > On 3/11/26 19:20, Zach van Rijn via cfarm-users wrote:
> > > ...
> > > 
> > > Does adding all users (and new users by default) to both of
> > > these groups make sense, or do you think there is a better
> > > way?
> > 
> > Given the names of those groups and the facts that they are
> > used for access control on those device nodes, I suspect that
> > 'video' and 'render' group membership are probably exactly the
> > intended permissions to use GPGPU on that system.
> 
> It certainly seems like that is the intended behavior:
> 
> ---
> root at cfarm109:~# grep -v ^# /etc/adduser.conf | uniq
> 
> EXTRA_GROUPS="audio gdm gpio i2c lightdm render video weston-
> launch"
> 
> ADD_EXTRA_GROUPS=1
> ---
> 
> I'm not clear why this isn't happening out of the box but it
> might be due to the way Ansible creates users.

Yes, Ansible runs useradd (the low-level utility) and not adduser (the
high-level utility on Debian/Ubuntu).  We already configure useradd in
/etc/default/useradd to set the default shell.  According to the man, you
should be able to set a GROUPS variable there (comma-separated without
whitespace).  If it works, it would be useful if you can add it in the
Ansible setup as an optional feature.

Baptiste