x11vnc and Dummy Monitor

Setup x11vnc

Install package:

$ apt install x11vnc

Set password:

$ x11vnc -storepasswd /etc/x11vnc.pass

Create x11vnc service:

$ vim /lib/systemd/system/x11vnc.service

[Unit]
Description=Start x11vnc at startup.
After=multi-user.target
[Service]
Type=simple
ExecStart=/usr/bin/x11vnc -auth guess -forever -loop -noxdamage -repeat -rfbauth /etc/x11vnc.pass -rfbport 5900 -shared
[Install]
WantedBy=multi-user.target

Enable the service:

$ systemctl enable x11vnc.service 
$ systemctl daemon-reload

Reboot.

Setup Dummy Monitor Driver

Install package:

$ apt install xserver-xorg-video-dummy

Configure xorg.conf:

$ vim /etc/X11/xorg.conf

Section "Device"
  Identifier  "Configured Video Device"
  Driver      "dummy"
EndSection

Section "Monitor"
  Identifier "Configured Monitor"
  HorizSync 31.5-48.5
  VertRefresh 50-70
EndSection

Section "Screen"
  Identifier "Default Screen"
  Monitor "Configured Monitor"
  Device "Configured Video Device"
  DefaultDepth 24
  SubSection "Display"
    Depth 24
    Modes "1920x1080"
  EndSubSection
EndSection