On 15 July 2016 at 13:46, Luís Matallui matallui@gmail.com wrote:
Hi,
I've just made a fresh Debian (Jessie) installation.
I've done the same with Debian 8.5 XFCE CD_1 in a local VM (amd64) - lightdm was installed and I logged in fine.
Then, I've added jessie-backports and installed lava-server from there. Once the installation completed, I've rebooted and the GUI desktop environment doesn't come up.
From messages over IRC, this was determined as being caused by apt
having to remove the lightdm package as part of the upgrade. I tried to reproduce this with the XFCE VM and the problem did not appear:
1 upgraded, 178 newly installed, 0 to remove and 103 not upgraded. Need to get 61.6 MB of archives. After this operation, 261 MB of additional disk space will be used.
(note the 0 to remove)
Since installation, all I'd done was: root@debian:~# cat /home/neil/root.history 1 apt install vim sudo screen 2 vi 3 apt update 4 apt install vim sudo screen 5 adduser neil sudo 6 vim /etc/apt/sources.list.d/backports.list 7 apt update 8 apt install -t jessie-backports lava-server
(The first operation with vi was because the CDROM wasn't disabled in the sources list)
Equally, over IRC, it was clear that reinstalling lightdm fixed the problem.
This happened twice already, so it's definitely the Lava installation that's breaking something there. Is this a known issue? Any suggestions?
I'm assuming it was a different desktop environment, triggering a different set of alternative packages.
If you have cause to repeat this, take a note of which packages are installed upon which lightdm depends - including the set of alternatives.
$ dpkg -s lightdm | grep Depends
Depends: libc6 (>= 2.14), libgcrypt20 (>= 1.6.0), libglib2.0-0 (>= 2.37.3), libpam0g (>= 0.99.7.1), libxcb1, libxdmcp6, debconf (>= 0.5) | debconf-2.0, lightdm-gtk-greeter | lightdm-greeter, dbus, libpam-systemd | consolekit, adduser
$ dpkg -l libc6 libgcrypt20 libglib2.0-0 libpam0g libxcb1 libxdmcp6 debconf debconf-2.0 lightdm-gtk-greeter lightdm-greeter dbus libpam-systemd consolekit adduser
Compare with this snippet: ii adduser 3.113+nmu3 all add and remove users a un consolekit <none> <none> (no description availa ii dbus 1.8.20-0+deb8u1 amd64 simple interprocess me ii debconf 1.5.56 all Debian configuration m un debconf-2.0 <none> <none> (no description availa ii libc6:amd64 2.19-18+deb8u4 amd64 GNU C Library: Shared ii libgcrypt20:amd64 1.6.3-2+deb8u1 amd64 LGPL Crypto library - ii libglib2.0-0:amd64 2.42.1-1+b1 amd64 GLib library of C rout ii libpam-systemd:amd64 215-17+deb8u4 amd64 system and service man ii libpam0g:amd64 1.1.8-3.1+deb8u1+b1 amd64 Pluggable Authenticati ii libxcb1:amd64 1.10-3+b1 amd64 X C Binding ii libxdmcp6:amd64 1:1.1.1-1+b1 amd64 X11 Display Manager Co un lightdm-greeter <none> <none> (no description availa ii lightdm-gtk-greeter 1.8.5-2 amd64 simple display manager
For the benefit of anyone finding this thread via the lava-users mailing list archive, try this command if you have lightdm installed:
$ sudo apt -t jessie-backports install lava-server lightdm
This tells apt to keep lightdm and install lava-server. On my tests, in XFCE, apt is quite happy so I can only assume that other desktops change the package list installed by lightdm. As apt was able to install lightdm after lava-server was installed from backports on Luis' test system (confirmed over IRC), this is not a permanent problem and the alternative dependencies are still satisfied with both packages installed. So asking apt to explicitly select both should allow apt to sort out what needs to be done.
If you or someone else repeats such an install, please let us know the logs of what apt did when asked to keep lightdm and install lava-server alongside. There should not be any reason for these two to cause issues, so there's a bug somewhere - presumably triggered by one of the other desktops available via Debian. lava-server itself is unlikely to be able to fix it as that would probably mean adding a dependency to lava-server for something which is only needed to keep lightdm and the problematic desktop happy. Most installs of lava-server have no desktop requirements. Even so, it would be useful to know where the bug lies.