Ubuntu Desktop Disable Graphics (X11) on Boot
If KasmVNC is used to publish Ubuntu Desktops over the network via VNC, the KasmVNC service will launch its own X11 instance with full fledged desktop environment.
The the console graphics can be disabled to save CPU/RAM if the user connects to the Ubuntu Desktop only via KasmVNC. By default Ubuntu Desktop will boot into X11 graphics on the console and two X11 servers will run (console and KasmVNC) and consume additional CPU/RAM.
root@ubuntu:~# systemctl get-default
graphical.target
root@ubuntu:~# systemctl set-default multi-user.target
Created symlink /etc/systemd/system/default.target → /lib/systemd/system/multi-user.target.
# reboot and testSteps to Disable Graphics on Boot
root@ubuntu:~# systemctl get-default
graphical.target
root@ubutu:~# systemctl list-units --type=target
UNIT LOAD ACTIVE SUB DESCRIPTION
basic.target loaded active active Basic System
cryptsetup.target loaded active active Local Encrypted Volumes
getty-pre.target loaded active active Preparation for Logins
getty.target loaded active active Login Prompts
graphical.target loaded active active Graphical Interface
local-fs-pre.target loaded active active Preparation for Local File Systems
local-fs.target loaded active active Local File Systems
multi-user.target loaded active active Multi-User System
network-online.target loaded active active Network is Online
network-pre.target loaded active active Preparation for Network
network.target loaded active active Network
nss-lookup.target loaded active active Host and Network Name Lookups
nss-user-lookup.target loaded active active User and Group Name Lookups
paths.target loaded active active Path Units
remote-fs.target loaded active active Remote File Systems
slices.target loaded active active Slice Units
snapd.mounts-pre.target loaded active active Mounting snaps
snapd.mounts.target loaded active active Mounted snaps
sockets.target loaded active active Socket Units
sound.target loaded active active Sound Card
swap.target loaded active active Swaps
sysinit.target loaded active active System Initialization
time-set.target loaded active active System Time Set
timers.target loaded active active Timer Units
veritysetup.target loaded active active Local Verity Protected Volumes
LOAD = Reflects whether the unit definition was properly loaded.
ACTIVE = The high-level unit activation state, i.e. generalization of SUB.
SUB = The low-level unit activation state, values depend on unit type.
25 loaded units listed. Pass --all to see loaded but inactive units, too.
To show all installed unit files use 'systemctl list-unit-files'.
root@ubuntu:~# systemctl set-default multi-user.target
Created symlink /etc/systemd/system/default.target → /lib/systemd/system/multi-user.target.
root@ubuntu:~# systemctl get-default
multi-user.target