Reconfigure the display-manager non-interactively












0















I am trying to change the default display-manager on a Ubuntu 18.04.1 in a non-interactive way to do this in a script.



Everything works as expected when using




  • dpkg-reconfigure gdm3

  • dpkg-reconfigure lightdm


I tried setting shared/default-x-display-manager to a valid display-manager and run dpkg-reconfigure, but that did not do the trick.





First check which display-manager is set.



root@host:~# cat /etc/X11/default-display-manager
/usr/sbin/gdm3
root@host:~# cat /etc/X11/default-display-manager
/usr/sbin/gdm3




Then set shared/default-x-display-manager to lightdm and validate it.



root@host:~# echo set shared/default-x-display-manager lightdm | debconf-communicate 
0 value set
root@host:~# echo get shared/default-x-display-manager | debconf-communicate
0 lightdm




Finally run dpkg-reconfigure --frontend noninteractive lightdm and check which display-manager is active. Which unfortunately is gdm3 again.



root@host:~# dpkg-reconfigure --frontend noninteractive lightdm
root@host:~# echo get shared/default-x-display-manager | debconf-communicate
0 gdm3
root@host:~# cat /etc/X11/default-display-manager
/usr/sbin/gdm3
root@host:~# ll /etc/systemd/system/display-manager.service
lrwxrwxrwx 1 root root 32 Jan 31 20:03 /etc/systemd/system/display-manager.service -> /lib/systemd/system/gdm3.service




The same happens if I want to switch from lightdm to gdm3.

Anything I am missing here or is this not intended to work at all?



I have seen in the scripts for gdm3 that if there is a /etc/X11/default-display-manager.debconf-update file, the systemd unit and the /etc/X11/default-display-manager are updated accordingly.

Unfortunately this does not work for lightdm as this one uses some other method(s) to do the work.



Hope someone else can shed some light on this and knows a convenient way to configure the display-manager non-interactively.










share|improve this question



























    0















    I am trying to change the default display-manager on a Ubuntu 18.04.1 in a non-interactive way to do this in a script.



    Everything works as expected when using




    • dpkg-reconfigure gdm3

    • dpkg-reconfigure lightdm


    I tried setting shared/default-x-display-manager to a valid display-manager and run dpkg-reconfigure, but that did not do the trick.





    First check which display-manager is set.



    root@host:~# cat /etc/X11/default-display-manager
    /usr/sbin/gdm3
    root@host:~# cat /etc/X11/default-display-manager
    /usr/sbin/gdm3




    Then set shared/default-x-display-manager to lightdm and validate it.



    root@host:~# echo set shared/default-x-display-manager lightdm | debconf-communicate 
    0 value set
    root@host:~# echo get shared/default-x-display-manager | debconf-communicate
    0 lightdm




    Finally run dpkg-reconfigure --frontend noninteractive lightdm and check which display-manager is active. Which unfortunately is gdm3 again.



    root@host:~# dpkg-reconfigure --frontend noninteractive lightdm
    root@host:~# echo get shared/default-x-display-manager | debconf-communicate
    0 gdm3
    root@host:~# cat /etc/X11/default-display-manager
    /usr/sbin/gdm3
    root@host:~# ll /etc/systemd/system/display-manager.service
    lrwxrwxrwx 1 root root 32 Jan 31 20:03 /etc/systemd/system/display-manager.service -> /lib/systemd/system/gdm3.service




    The same happens if I want to switch from lightdm to gdm3.

    Anything I am missing here or is this not intended to work at all?



    I have seen in the scripts for gdm3 that if there is a /etc/X11/default-display-manager.debconf-update file, the systemd unit and the /etc/X11/default-display-manager are updated accordingly.

    Unfortunately this does not work for lightdm as this one uses some other method(s) to do the work.



    Hope someone else can shed some light on this and knows a convenient way to configure the display-manager non-interactively.










    share|improve this question

























      0












      0








      0








      I am trying to change the default display-manager on a Ubuntu 18.04.1 in a non-interactive way to do this in a script.



      Everything works as expected when using




      • dpkg-reconfigure gdm3

      • dpkg-reconfigure lightdm


      I tried setting shared/default-x-display-manager to a valid display-manager and run dpkg-reconfigure, but that did not do the trick.





      First check which display-manager is set.



      root@host:~# cat /etc/X11/default-display-manager
      /usr/sbin/gdm3
      root@host:~# cat /etc/X11/default-display-manager
      /usr/sbin/gdm3




      Then set shared/default-x-display-manager to lightdm and validate it.



      root@host:~# echo set shared/default-x-display-manager lightdm | debconf-communicate 
      0 value set
      root@host:~# echo get shared/default-x-display-manager | debconf-communicate
      0 lightdm




      Finally run dpkg-reconfigure --frontend noninteractive lightdm and check which display-manager is active. Which unfortunately is gdm3 again.



      root@host:~# dpkg-reconfigure --frontend noninteractive lightdm
      root@host:~# echo get shared/default-x-display-manager | debconf-communicate
      0 gdm3
      root@host:~# cat /etc/X11/default-display-manager
      /usr/sbin/gdm3
      root@host:~# ll /etc/systemd/system/display-manager.service
      lrwxrwxrwx 1 root root 32 Jan 31 20:03 /etc/systemd/system/display-manager.service -> /lib/systemd/system/gdm3.service




      The same happens if I want to switch from lightdm to gdm3.

      Anything I am missing here or is this not intended to work at all?



      I have seen in the scripts for gdm3 that if there is a /etc/X11/default-display-manager.debconf-update file, the systemd unit and the /etc/X11/default-display-manager are updated accordingly.

      Unfortunately this does not work for lightdm as this one uses some other method(s) to do the work.



      Hope someone else can shed some light on this and knows a convenient way to configure the display-manager non-interactively.










      share|improve this question














      I am trying to change the default display-manager on a Ubuntu 18.04.1 in a non-interactive way to do this in a script.



      Everything works as expected when using




      • dpkg-reconfigure gdm3

      • dpkg-reconfigure lightdm


      I tried setting shared/default-x-display-manager to a valid display-manager and run dpkg-reconfigure, but that did not do the trick.





      First check which display-manager is set.



      root@host:~# cat /etc/X11/default-display-manager
      /usr/sbin/gdm3
      root@host:~# cat /etc/X11/default-display-manager
      /usr/sbin/gdm3




      Then set shared/default-x-display-manager to lightdm and validate it.



      root@host:~# echo set shared/default-x-display-manager lightdm | debconf-communicate 
      0 value set
      root@host:~# echo get shared/default-x-display-manager | debconf-communicate
      0 lightdm




      Finally run dpkg-reconfigure --frontend noninteractive lightdm and check which display-manager is active. Which unfortunately is gdm3 again.



      root@host:~# dpkg-reconfigure --frontend noninteractive lightdm
      root@host:~# echo get shared/default-x-display-manager | debconf-communicate
      0 gdm3
      root@host:~# cat /etc/X11/default-display-manager
      /usr/sbin/gdm3
      root@host:~# ll /etc/systemd/system/display-manager.service
      lrwxrwxrwx 1 root root 32 Jan 31 20:03 /etc/systemd/system/display-manager.service -> /lib/systemd/system/gdm3.service




      The same happens if I want to switch from lightdm to gdm3.

      Anything I am missing here or is this not intended to work at all?



      I have seen in the scripts for gdm3 that if there is a /etc/X11/default-display-manager.debconf-update file, the systemd unit and the /etc/X11/default-display-manager are updated accordingly.

      Unfortunately this does not work for lightdm as this one uses some other method(s) to do the work.



      Hope someone else can shed some light on this and knows a convenient way to configure the display-manager non-interactively.







      18.04 lightdm gdm display-manager






      share|improve this question













      share|improve this question











      share|improve this question




      share|improve this question










      asked 2 days ago









      ThomasThomas

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      3,77181527






















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