Custom OS Template (Linux)

Although DaDesktop maintains a number of popular Linux distros, there may be an occasion when a specific distro that is not available is required. DaDesktop are happy to support this for most mainline Linux distros. Please let us know where to download the ISO file and which server you would like to publish the Custom OS template to.

Important:

About Disk Partitioning
1. Customised templates require just one disk partition or two partitions: an EFI/Boot partition and a system and data partition.
2. An LVM partition is not supported; please do not use LVM.
3. The wrong partition scheme will cause automatic disk resizing and other functions to fail.

Linux Template

Once we've downloaded the ISO file to the server, you'll be able to find it under Admin Menu->OS IMAGES->ISO FILES in your account.

Then you can prepare the template via Admin Menu->OS IMAGES->CUSTOM OS TEMPLATES

Please follow this guide carefully and complete all the steps, otherwise full DaDesktop functionality may not work.

Install the OS
Set the default username to "student"; password to "student"
Set the "student" account to auto-login
Use DaDesktop or your own branded wallpaper
Some distros now default to using Wayland as their display driver. Although Wayland works with DaDesktop, for now we recommend reverting to X11.

To disable Wayland:

edit /etc/gdm/custom.conf, e.g.
```
# Uncomment the line below to force the login screen to use Xorg
        WaylandEnable=false
        
```
log out and log in again
Install spice-vdagent – using your package manager is usually the best approach. NB: this may already be installed, depending on your distribution.
- After a successful installation, restart the machine; you should then see the two running processes: spice-vdagent and spice-vdagentd
Install qemu-guest-agent – again, using your package manager is usually the best approach
Install X11VNC. NB: for some distributions, you may need to add extra repositories, such as the 'epel' repo for Red Hat-based distros like Oracle Linux or Rocky Linux

Configure X11VNC

Make sure X11VNC is installed
run the command sudo -i to open a root shell

run the command below, which allows X11VNC to auto-start on reboot

cat > /etc/xdg/autostart/x11vnc.desktop <<EOF
                [Desktop Entry]
                Type=Application
                Exec=/usr/bin/x11vnc -N -no6 -rfbportv6 -1 -allow 10.0.3.1 -nopw -shared -alwaysshared -forever -repeat -nowireframe -noscr -nocursorshape -skip_lockkeys -cursor_drag -grab_buster -deferupdate 10 -speeds 6000,5000,20 -afteraccept announce-vnc-users.sh -gone announce-vnc-users.sh
                Hidden=false
                X-MATE-Autostart-enabled=true
                X-MATE-AutoRestart=true
                Name[en_US]=X11VNC
                Name=X11VNC
                Comment[en_US]=Share desktop over VNC
                Comment=Share desktop over VNC
                EOF

Create the desktop notification script by running the following commands

cat > /usr/local/bin/announce-vnc-users.sh <<EOF
        notify-send -a x11vnc "VNC users connected: $RFB_CLIENT_COUNT"
        EOF
        chmod +x /usr/local/bin/announce-vnc-users.sh

Reboot
Check the firewall settings, i.e., ensure TCP port 5900 is open. For example:

ss -pntl
Disable the sudo password (recommended)
Verify success

When you connect, if the URL changes to a new one with a token query parameter, you're good to go. This means X11VNC is working. The text box at the bottom left of the screen – used for copy/paste between your own desktop and virtual desktop – should now be operational.

Please Note

To add additional optional features, such as

DDWebdav to allow the Trainer's content folders to be synchronised to each participant's machine,
or DDUpload – to easily upload files to a DaDesktop machine;

Please contact DaDesktop Tech Support.