Ubuntu 16.04 – x11vnc running at startup

Abbreviated version of setting up x11vnc on Ubuntu 16.04 based systems:

sudo x11vnc -storepasswd /etc/x11vnc/passwd
sudo vi /lib/systemd/system/x11vnc.service

[Unit]
Description=Start x11vnc at startup.
After=multi-user.target

[Service]
Type=simple
ExecStart=/usr/bin/x11vnc -xkb -auth /var/run/lightdm/root/:0 -noxrecord -noxfixes -noxdamage -rfbauth /etc/x11vnc/passwd -forever -bg -nodpms -rfbport 5900 -rfbversion 3.6 -permitfiletransfer -shared -dontdisconnect -alwaysshared -o /var/log/x11vnc.log

[Install]
WantedBy=multi-user.target

sudo systemctl enable x11vnc.service
sudo systemctl daemon-reload
sudo service x11vnc restart

Source: Ubuntu 16.04 – Configure your system to have x11vnc running at startup – Griffon’s IT Library