Custom OS Template (Linux)

Although DaDesktop maintains a number of popular Linux distros, there may be times when you need a specific distro that isn't available. DaDesktop are happy to support this for most mainstream Linux distros. Please let us know where we can download the ISO file and which server you'd like to use to publish the Custom OS template.

Important:

About Disk Partitioning
1. Customised templates require only one disk partition or two partitions: one EFI/Boot partition and the other system and data partition.
2. An LVM partition is not supported, please do not use LVM
3. The wrong partition scheme will cause disk auto-resize and other features to fail.

Linux Template

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

You can then prepare the template under Admin Menu->OS IMAGES->CUSTOM OS TEMPLATES

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

Install the OS
Set the default username to "student" and the password to "student"
Enable auto-login for the "student" account
Use DaDesktop or your own brand wallpaper
Some distros now default to using Wayland as their display driver. Although Wayland works in 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 back in
Install spice-vdagent using your package manager; this is usually the best approach. Note: This may already be installed depending on your distro
- After installing it, restart the machine and you should see two processes running: spice-vdagent and spice-vdagentd
Install qemu-guest-agent; again, using your package manager is usually the best approach
Install X11VNC. Note: For some distros, you may need to add extra repos, such as the 'epel' repo for Red Hat-based distros like Oracle Linux or Rocky Linux

Configure X11VNC

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

run the following command, which enables X11VNC to start automatically 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 a 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: make sure TCP port 5900 is open, e.g.

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

When connecting, if the URL changes to include 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 and paste between your local desktop and the virtual desktop, should now be working as well.

Please Note

To add extra 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.