Custom OS Template (Linux)

Although DaDesktop maintains a range of popular Linux distros, occasionally you may need a particular distro that isn't listed. We're pleased to accommodate most mainstream Linux distros. Please let us know where to download the ISO file and on which server in Portugal you'd like 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 another for the system and data.
2. LVM partitions are not supported – please do not use LVM.
3. Using the wrong partitioning scheme will cause automatic disk resizing and other functions to fail.

Linux Template

Once we've downloaded the ISO file onto the server, you'll find it listed 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 every step; otherwise, DaDesktop might not function correctly.

1. Install OS
2. Set the default username to "student" and the password to "student"
3. Enable auto login for the "student" account
4. Use the DaDesktop wallpaper or your own branded wallpaper
   

5. Some distros now default to Wayland for their display driver. While Wayland is functional in DaDesktop, we currently advise 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.

6. Install spice-vdagent. Using your package manager is generally the best method. Note: This may already be installed depending on your distro.
   • After a successful installation, restart the machine, and you should see two running processes: spice-vdagent and spice-vdagentd
   • 
7. Install qemu-guest-agent – again, using your package manager is typically the best approach.
8. Install X11VNC. Note: For some distros, you may need to add additional repositories, such as the 'epel' repo for Red Hat-based distributions like Oracle Linux or Rocky Linux.
9. Configure X11VNC
   • Ensure X11VNC is installed.
   • Run sudo -i to open a root shell.

   • Run the following command to enable 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

10. Create a desktop notification script by running the commands below:

    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

11. Reboot

12. Check the firewall settings, i.e., ensure TCP port 5900 is open, for example, by running

    ss -pntl

13. Disable the sudo password (recommended).

14. Verify success

    When you connect, if the URL changes to a new one with a token query parameter, then everything is working. This confirms that X11VNC is operational. The text box in the bottom left of the screen, used for copy/paste between your desktop and the virtual desktop, should now also be functioning.

     

Please Note

To add extra optional features such as

• DDWebdav to allow trainer 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.