How to create desktop GUI on headless server (no monitor attached)

# ideally these are all done in a screen/tmux session
sudo su

apt-get update ; apt-get install -y xserver-xorg-video-dummy

# let's create a fake / virtual display device
echo 'Section "Device"' > /etc/X11/xorg.conf
echo '    Identifier  "Configured Video Device"' >> /etc/X11/xorg.conf
echo '    Driver      "dummy"' >> /etc/X11/xorg.conf
echo 'EndSection' >> /etc/X11/xorg.conf
echo '' >> /etc/X11/xorg.conf
echo 'Section "Monitor"' >> /etc/X11/xorg.conf
echo '    Identifier  "Configured Monitor"' >> /etc/X11/xorg.conf
echo '    HorizSync 31.5-48.5' >> /etc/X11/xorg.conf
echo '    VertRefresh 50-70' >> /etc/X11/xorg.conf
echo 'EndSection' >> /etc/X11/xorg.conf
echo '' >> /etc/X11/xorg.conf
echo 'Section "Screen"' >> /etc/X11/xorg.conf
echo '    Identifier  "Default Screen"' >> /etc/X11/xorg.conf
echo '    Monitor     "Configured Monitor"' >> /etc/X11/xorg.conf
echo '    Device      "Configured Video Device"' >> /etc/X11/xorg.conf
echo '    DefaultDepth 24' >> /etc/X11/xorg.conf
echo '    SubSection "Display"' >> /etc/X11/xorg.conf
echo '    Depth 24' >> /etc/X11/xorg.conf
echo '    Modes "1024x800"' >> /etc/X11/xorg.conf
echo '    EndSubSection' >> /etc/X11/xorg.conf
echo 'EndSection' >> /etc/X11/xorg.conf

shutdown -r now

# start GUI
startx

# open another screen/tmux

# install xrdp
# so we can remote screen to X / desktop
apt-get install xrdp
adduser xrdp ssl-cert

nano /etc/xrdp/xrdp.ini

# make sure there's this line to ensure secure access to xrdp
# (forcing xrdp to listen to 127.0.0.1 port 3389)
# port=tcp://.:3389

systemctl restart xrdp



##########
# Then you can connect to the GUI by creating an SSH Tunnel to 127.0.0.1 port 3389 on server
#ssh -v -L 3389:localhost:33890 -N    myusername@myserver.com


# then connect to port 33890 - voila, server's GUI
#rdesktop localhost:33890