How to install XCP-NG guest utilities on OpenSUSE LEAP 15.6

Problem

The guest additions CD does not work for installing the XCP-NG guest utilities on OpenSUSE LEAP 15.6:

Unknown Linux distribution `opensuse-leap`

Solution

OpenSUSE LEAP 15 will automatically install the Xen guest utilities during its installation process. However, if you need to install them manually, you can do so by inserting the XCP-NG guest utilities ISO into the virtual machine’s CD drive and run the following command as root:

mount /dev/sr0 /mnt
cd /mnt/Linux
./install.sh -d sles -m 15

This way, you are forcing the installer to use the SLES (SUSE Linux Enterprise Server) installation script, which is compatible with OpenSUSE LEAP 15.6.