Custom OS Template (Linux)

Although DaDesktop keeps up a number of popular Linux distros, there may be times when you need a specific one that isn't available. DaDesktop is happy to support this for most mainline Linux distros. Just let us know where to download the ISO file and which server you'd like to use to publish the Custom OS template.

Important:

About Disk Partitioning
1. Customized templates need a single disk partition or two partitions: one for EFI/Boot and the other for the system and data.
2. An LVM partition is not supported, so please avoid using LVM.
3. Using the wrong partition scheme will stop disk auto-resize and other features from working properly.

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.

Then you can get the template ready under Admin Menu->OS IMAGES->CUSTOM OS TEMPLATES

Please follow this guide carefully and complete every step, otherwise full DaDesktop functionality is likely to be affected.

Install OS
Set the default username to "student"; password to "student"
Set the "student" account to Auto Login
Use DaDesktop or your own brand wallpaper
Some distros now come with Wayland as the default display driver. While Wayland does work in DaDesktop, we currently recommend switching back 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 way. Note: this might already be installed, depending on your distro.
- After a successful install, restart the machine and you should see two running processes, spice-vdagent and spice-vdagentd
Install qemu-guest-agent. Again, your package manager is usually the best approach.
Install X11VNC. Note: for some distros, you may need to add extra repos, like the 'epel' repo for Red Hat-based distros such as 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 to allow 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 a desktop notify 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

Reboot
Check the firewall setting, i.e., make sure TCP port 5900 is open, using:

ss -pntl
Disable sudo password (recommended)
Verify success

When you connect, if the URL changes to include a token query parameter, then you're good to go. This confirms X11VNC is working. The text box at the bottom left of the screen, which handles copy/paste between your own desktop and the virtual desktop, should now also be functional.

Please Note

To add extra optional features such as

DDWebdav to sync the trainer's content folders to each participant machine,
or DDUpload to easily upload files within a DaDesktop machine;

Please contact DaDesktop Tech Support.