lightdm or gdm?

[Dimitri John Ledkov]

On 19 April 2017 at 15:32, Sebastien Bacher <seb128 at ubuntu.com> wrote:
> Hey there,
>
> That's a topic that was mentioned during the meeting yesterday and
> something we need to decide on early in the cycle since there is going
> to be work needed on that front to have a fully working session.
>
> I'm doing a small summary of what I think are the pro (+) and con (-) of
> each
>
> * lightdm
>
> + well tested in Ubuntu
> + we have people in the team knowing the codebase
> + shared with other flavors/greeters selection
> + guest session
> - divergence from upstream
> - we are the maintainers so it's more work for us
> - gnome-shell uses gdm for its lockscreen so work is needed to make it
> work with lightdm
>
> * gdm
>
> + that's the GNOME solution, works today with wayland & gnome-shell
> - we started lightdm because we found the gdm codebase not easy to work
> on, that might still be true
> - ?keeps an active session from the greeter even after logging which
> uses resources? (it was mentioned on IRC, to be confirmed, is that
> needed due to the lockscreen?)
> - no guest session, we need to work on that or decide to drop the
> feature from Ubuntu
>

Currently, in ubiquity we maintain a barebones ubiquity-dm which is
very DE which somewhat mimiced unity experience - it has a panel and
launches indicators, and offers users to run ubiquity installer under
it, or click the "Try Ubuntu" to skip through lightdm into a live
desktop session.

Ideally, I would like to drop that code in-favor of using gdm +
gnome-shell in the installer/app mode. As far as I understand during
live-session we use "ubuntu" user, and we do not by default show login
manager (lightdm) UI nor offer guest session.

(Well, the system indicator allows one to switch into guest session
mode, but said indicator will not be available anyway)

>
> I talked a bit with Robert yesterday who said he could make lightdm use
> the gdm greeter (he has some work started on that a few cycles ago)
> which means it could be used as GNOME lockscreen instead of gdm. He's
> probably the best placed to comment on the work and pro/con of the
> solutions though so I'm going to let him go into the details when he
> replies.
>

I think that would be nice, if we could use gdm as a lightdm greeter
to get the guest sessions. I did enquire if that is at all possible
during release sprint too.

Or try again for GDM to provide guest sessions?

Can guest sessions be improved with lxd containers at all? E.g. spawn
an ephemeral container that pretends to be user ubuntu, when in fact
it is namespaced away and self-destructs on log out?

-- 
Regards,

Dimitri.