16.04: Graphical login/desktop vanished? (coming closer)

Josef Wolf jw at raven.inka.de
Tue Jul 26 11:34:40 UTC 2016

Hello all,

First, I want to thank for all the support that was offered on this list.

Then, I want to answer all the questions I was asked in this thread and have
not yet answered. I answer them all at once in this mail instead of cluttering
them across the thread.

To sum up: the core of the problem was that on a freshly installed 16.04

  "aptitude -q -y remove network-manager"

did remove the whole graphical desktop. (almost 600 packages)

Strange enough, /etc/init.d/lightdm was still there and was actually invoked
by systemd. Running it by hand did not produce any diagnostics. Therefore, I
(erronously) assumed lightdm is still there but fails to start.

That box was a clean install of 16.04, not an upgrade.

Ralf Mardorf asked:
> I pointed out that something is fishy with the OP's install.
> IOW 1. lightdm isn't removed
>     2. /etc/init.d/lightdm is the wrong location, there should be a
>     systemd unit instead

This WAS a fresh install of 16.04.

Lightdm WAS removed.

/etc/init.d/lightdm WAS the correct file name. Actually, it was a shell
script with start/stop stuff etc. I know for sure, because it was by checking
this script how I found that it tries to start /usr/sbin/lightdm. Only
THEN I got the clue that /usr/sbin/lightdm is missing and started to
investigate why it is missing.

Ralf Mardorf asked:
> Regarding the original topic and the lightdm related issue:
> Josef, what is the output of
>  dpkg -l lightdm

Sorry, I can't check anymore. I tried to reinstall the desktop and got a
completely different desktop, which I've never seen before.

Since I always try to stay as close as possible with default installs, I
decided to wipe everything and do a fresh clean reinstall.

Ralf Mardorf asked:
> Are you using a third party repository?

No. I have not yet figured out how to properly activate them in a scripted
way. I generally avoid manual configuration adjustments as much as possible.

Oliver Gravert states:
> do you use something else or do you just configure your network in
> /etc/network/interfaces?

It depends. I have hosts with very different requirements. There are ordinary
laptops. But there are also routers (cable/DSL) and internal routers (havng
LOTS of VLAN devices.

All my setups are heavily scripted/automated. Thereofre, I tend not to
introduce multiple different ways to set up things. Since the routers are set
up without NM, I decided to do the same for the desktops/laptops also. After
all, it's not a rocket science.

> ... not sure what happens if we at any point switch to systemd-networkd from
> ifupdown

Umm... Will have to change things again? What is the plan?

> so you can safely let it installed and just do your network config via
> command line

Last time I checked network-manager was in 06/2010. I don't even remember the
reasons why it did not fit. It must have been either
- the inablility to query and configure it via command line and/or files
- Or it was that a user needed to log into the desktop to activate NM.

Anyway, people in this thread say NM has matured since then. So I'll check it
out again.

Will I have to remove wpa_supplicant, or will NM sit on top of wpa_supplicant?

Any pointers to how configure NM in a scripted manner?

> (then it will also still provide the info to desktop apps on
> the dbus that the system is off/online, many apps use that feature nowadays)

Do you have a pointer? Maybe this would be a viable interface for quering and
configuring the network stuff?

Oliver Grawert wrote:
> had you used apt instead of
> aptitude lightdm would have not been removed alongside, aptitude
> uninstalls recommends by default i think ... apt does not do that.

So what is the recommendation for AUTOMATED and UNATTENDED installs/removals
of packages?

It looks like preference has moved from apt-get to aptitude back to
apt-get. In addition, command line options have been renamed several times in
the past.

Josef Wolf
jw at raven.inka.de

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