Ubuntu 16.04 headless – resolution stuck @ 1024×768

[Kernel]

Hi everyone,

I installed the normal NoMachine package on Ubuntu 16.04 and it works great. As long as there is a real screen attached. I can choose other resolutions, etc.

But when I disconnect the screen and reboot, NoMachine login is stuck at 1024×768. Ubuntu display preferences does not display any options and does not show any resolution or orientation, etc.

xrandr tells me this:

Screen 0: minimum 8 x 8, current 1024 x 768, maximum 32767 x 32767

VGA1 disconnected (normal left inverted right x axis y axis)

VIRTUAL1 disconnected (normal left inverted right x axis y axis)

So… basically it tells me that there is no screen connected. Neither a real one nor virtual ones. I also cannot add resolutions to the xorg configuration via xrandr because I have to define which screen this resolution belongs to.

My question is: How can I solve this problem?

I want to be able to add any resolution I like, I want to be able to switch to any resolution I like and the best option would be that the server resolution changes according to the window size that the NoMachine client on my computer that access the NoMachine server uses. I tried everything in the NoMachine client configuration like custom resolutions and change server resolution, etc. None works.

Any ideas?

[graywolf]

You can get such a behavior if you let NoMachine create a display on the fly rather than using thephysical one. Try to turn off lightdm:
sudo service lightdm stop

and restart NoMachine server:
sudo /usr/NX/bin/nxserver --restart

Otherwise, if video card is NVIDIA, you can force Xorg to work as if a monitor were attached (see NVIDIA-specific option “CustomEDID” in xorg.conf).

 

[thetravellor]

Hi, I was searching for a solution to this too.

If the machine is truly headless, you do not actually need the display manager running, as NoMachine will handle it.

Also the OP mentioned Ubuntu 16, which uses systemd to control services.

So.

Stop desktop manager

sudo systemctl stop lightdm

Restart nxserver

sudo systemctl restart nxserver.service

Is it running?

:~$ sudo systemctl status nxserver
● nxserver.service – NoMachine Server daemon
Loaded: loaded (/lib/systemd/system/nxserver.service; enabled; vendor preset: enabled)
Active: active (exited) since Thu 2016-05-19 20:15:04 AEST; 1h 46min ago
Main PID: 17685 (code=exited, status=0/SUCCESS)
CGroup: /system.slice/nxserver.service
├─17695 /usr/NX/bin/nxserver.bin root 17685 –daemon
├─17710 /usr/NX/bin/nxd
├─18092 /usr/NX/bin/nxserver.bin -c /etc/NX/nxserver –login -H 5
└─18116 /usr/NX/bin/nxserver.bin –virtualsession –sessionid A487F762AF159AC0B69660489C44F41B

May 19 20:15:03 server systemd[1]: Starting NoMachine Server daemon…
May 19 20:15:03 server nxserver[17685]: NX> 161 Enabled service: nxserver.
May 19 20:15:04 server nxserver[17685]: NX> 162 Disabled service: nxnode.
May 19 20:15:04 server nxserver[17685]: NX> 161 Enabled service: nxd.
May 19 20:15:04 server systemd[1]: Started NoMachine Server daemon.
May 19 20:15:49 server nxexec[18128]: pam_unix(nx:session): session opened for user user by (uid=125)
May 19 20:15:57 server nxexec[18775]: pam_unix(nx:session): session opened for user user by (uid=125)

Or this if you used the CLI

sudo /usr/NX/bin/nxserver –restart

NX> 162 Disabled service: nxserver.
NX> 162 Disabled service: nxnode.
NX> 162 Disabled service: nxd.
NX> 161 Enabled service: nxserver.
NX> 162 WARNING: Cannot find X servers running on this machine.
NX> 162 WARNING: A new virtual display will be created on demand.
NX> 161 Enabled service: nxd.

If the machine is headless, do not need lightdm service to start at all (obviously dont do this on a machine with a real monitor)

sudo systemctl disable lightdm

So is lightdm running? Yes it is because NoMachine started it,

user@server:~$ ps -ef | grep lightdm
user  15079  5887  0 22:09 pts/19   00:00:00 grep –color=auto lightdm

You can now resize you NoMachine window

Image available at http://imgur.com/a/WsPCu (NoMachine Graphics Settings)

[graywolf]

Hi, I was searching for a solution to this too.

Hello, thank you for sharing your solution.

[Author]

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