Runcloud installation script has dependency of 2 packages which does not comes in by default in some Ubuntu images that Hetzner provides (Eg: Ubuntu-20.04-minimal).
That is why installation script may fail and runcloud-agent might not start. To fix the issue you must run the following command before running the installation script.
sudo apt install gnupg libmagic1 -yThe gnupg package is required to import 3rd party repositories such as MariaDB where libmagic1 package is required by runcloud-agent service.