Convert Ubuntu Desktop to Behave Like Ubuntu Server (No Display)#

This guide turns an Ubuntu Desktop installation into a headless, console-only system that behaves like Ubuntu Server — no graphical login, no desktop environment loaded at boot. It applies to both Ubuntu 24.04 LTS and Ubuntu 26.04, which both use systemd and the gdm3 display manager.

Background: What Each Command Does#

Command

Purpose

systemctl set-default multi-user.target

Sets the default boot target to multi-user (text/console, networking, no GUI) instead of graphical.

systemctl disable --now gdm3

Stops gdm3 immediately and removes it from the boot sequence.

apt install ubuntu-server

Installs the Ubuntu Server package set before the desktop package set is removed.

apt purge ubuntu-desktop ubuntu-desktop-minimal gdm3

Removes the Ubuntu Desktop metapackages and graphical login manager.

apt autoremove --purge

Removes dependencies that APT no longer considers necessary. Review its proposed changes before accepting them.

reboot

Restarts so the machine comes up in console-only mode.

About the Two systemd “Targets”#

  • graphical.target → boots into the full desktop with a graphical login (GDM).

  • multi-user.target → boots into a multi-user text console (like Ubuntu Server).

multi-user.target is the standard target used by Ubuntu Server, which is why switching to it makes a Desktop install behave like a Server install.

Step-by-Step#

1. Set the Default Boot Target to Console#

sudo systemctl set-default multi-user.target

Expected output:

Created symlink '/etc/systemd/system/default.target' → '/usr/lib/systemd/system/multi-user.target'.

2. Stop and Disable the Display Manager#

Ubuntu Desktop uses gdm3 by default:

sudo systemctl disable --now gdm3

Run this command from a text console or an SSH session. It immediately ends any active graphical login sessions.

Expected output:

Synchronizing state of gdm3.service with SysV service script...
Removed '/etc/systemd/system/display-manager.service'.

3. Make Sure the GPU PF Has No Clients#

Before removing the desktop packages, verify that no process is using a Direct Rendering Manager (DRM) device belonging to the GPU physical function (PF). First identify the GPU PF’s PCI address:

lspci -D | grep -Ei 'VGA|Display'

For example, if the address is 0000:00:02.0, list its DRM device nodes:

GPU_PF=0000:00:02.0
find -L /dev/dri/by-path -maxdepth 1 -type c \
  -name "pci-${GPU_PF}-*" -print

Check those nodes for clients:

sudo fuser -v /dev/dri/by-path/pci-${GPU_PF}-*

No output means that the PF has no clients. If processes are listed, stop the associated service or application and run the check again. Do not continue until the command produces no output. If gdm, gnome-shell, Xorg, or Xwayland appears, confirm that gdm3 was stopped in the previous step.

4. Remove the Desktop Packages#

Install the Ubuntu Server package set first. This keeps packages shared with a server installation from being selected for automatic removal:

sudo apt update
sudo apt install ubuntu-server

Preview the desktop purge and review the packages listed for removal:

sudo apt-get --simulate purge ubuntu-desktop ubuntu-desktop-minimal gdm3

If the proposed changes are safe for the deployment, remove the desktop metapackages and display manager:

sudo apt purge ubuntu-desktop ubuntu-desktop-minimal gdm3

Finally, preview the unused dependencies. This list can be much larger than the first purge:

sudo apt-get --simulate autoremove --purge

Review every package in the removal summary, especially when working remotely. Do not continue if it includes a package required by the deployment. When the proposed changes are safe:

sudo apt autoremove --purge

5. Reboot#

sudo reboot

The system now boots to a text console login, like Ubuntu Server.

Verify the Change#

After rebooting, log in at the console and run:

# Should print: multi-user.target
systemctl get-default

# Should print inactive and disabled, or report that gdm3 is not installed
systemctl is-active gdm3
systemctl is-enabled gdm3

# Confirm no graphical target is active
systemctl status graphical.target

You can also confirm no X/Wayland session is running:

# Should return nothing (no display server processes)
pgrep -a "Xorg|Xwayland|gnome-shell"

Confirm that the desktop package sets are no longer installed:

# Should return no lines beginning with "ii"
dpkg-query -W -f='${db:Status-Abbrev} ${binary:Package}\n' \
  ubuntu-desktop ubuntu-desktop-minimal gdm3 2>/dev/null | grep '^ii'