Custom OS Template (Linux)

While DaDesktop already offers several popular Linux distributions, there may be times when you need a specific one that isn't yet available. For most mainstream distros, we're happy to help. Just let us know where to fetch the ISO file and which server you'd like the Custom OS template deployed to.

Important:

About Disk Partitioning
1. Custom templates require a single partition, or at most two: one EFI/Boot partition and a separate system/data partition.
2. LVM partitions aren't supported — please avoid using LVM entirely.
3. An incorrect partition scheme will break automatic disk resizing and other key functions.

Linux Template

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

From there, you can prepare the template under Admin Menu->OS IMAGES->CUSTOM OS TEMPLATES.

Please follow this guide step by step — skipping any step may prevent DaDesktop from operating correctly.

Install the operating system.
Set the default username to "student" and the password to "student".
Enable automatic login for the "student" account.
Apply the DaDesktop wallpaper, or one with your own branding
Some distributions now use Wayland by default for display. While Wayland works with DaDesktop, we currently recommend switching back to X11.

To disable Wayland:

Edit /etc/gdm/custom.conf, for example:
```
# 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 is usually the easiest method. (Note: It may already be installed, depending on your distro.)
- After installation, restart the machine. You should see two running processes: spice-vdagent and spice-vdagentd.
Install qemu-guest-agent, again preferably via your package manager.
Install X11VNC. For some distros — especially Red Hat–based ones like Oracle Linux or Rocky Linux — you may need to add extra repositories, such as the 'epel' repo.
Set up X11VNC
- Confirm that X11VNC is installed.
- Open a root shell by running sudo -i.
- Execute the following command to make X11VNC start automatically on boot:
```
cat > /etc/xdg/autostart/x11vnc.desktop <
```
Create a desktop notification script by running these commands:
```
cat > /usr/local/bin/announce-vnc-users.sh <
```
Restart the system.
Check the firewall settings — ensure TCP port 5900 is open, for instance by running:

ss -pntl
Disable the sudo password (recommended).
Verify that everything is working.

When you connect, if the URL changes to include a token query parameter, you're good to go. That confirms X11VNC is active. The text box in the bottom-left corner of the screen — which enables copy/paste between your local desktop and the virtual one — should now be functional.

Please Note

If you'd like to add extra optional features, such as:

DDWebdav – synchronises the trainer's content folders to each participant's machine,
or DDUpload – makes it easy to upload files directly into a DaDesktop session;

get in touch with DaDesktop Tech Support.