Custom OS Template (Linux)

Although DaDesktop maintains a number of popular Linux distros, you might occasionally need a version that's not available in Hong Kong. For most mainstream distributions, we're happy to support this. Just let us know where to download the ISO file and which server you want to use to publish the Custom OS template.

Important:

About Disk Partitioning
1. Custom templates should have just one disk partition or two: one EFI/Boot partition and the other for the system and data.
2. LVM partitions aren’t supported, so please avoid using LVM.
3. Choosing an incorrect partition scheme will break disk auto-resize and other functions.

Linux Template

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

Then you can create the template from Admin Menu->OS IMAGES->CUSTOM OS TEMPLATES

Please follow this guide carefully and complete every step, otherwise DaDesktop may not function correctly.

Install the OS
Set the default username to "student" and the password to "student"
Configure the "student" account for automatic login
Use the 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 suggest switching 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
        
```
logout and login again
Install spice-vdagent, using your package manager is usually the best approach. NB This may already be installed depending on your distro
- After correct installation, restart the machine, and you should see the two running processes, spice-vdagent and spice-vdagentd
Install qemu-guest-agent, again using your package manager is usually the simplest route
Install X11VNC. NB For some distros, you may need to add extra repos such as the 'epel' repo for Redhat based distros, such as Oracle Linux or Rocky Linux

Configure X11VNC

make sure X11VNC installed
run command sudo -i to open root shell

run the below command 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 desktop notify script by running below 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 firewall setting, ie make sure TCP port 5900 is open, e.g.

ss -pntl
Disable sudo password ( recommended )
Verify success

When you connect, if the URL changes to include a token query parameter, you're good to go. This means X11VNC is working. And the text box at the bottom left of the screen, used for copy/paste between your local desktop and the virtual desktop, should now be functional.

Please Note

To add extra optional features such as

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

Please contact DaDesktop Tech Support.