Make Preseed iPXE compatible with bootdisk and non-interactive installation of Ubuntu
If you deploy Ubuntu with internal domains like .example.test and the domain is not already set on the PXELinux/iPXE-template or it is set by the DHCP, the preseed installation stops to ask you if the domain you entered in the preseed file is correct. With this the installation is not non-interactive and you have to connect to the console of the machine to continue the installation.
In a setup without DHCP and using the bootdisk-deployment the iPXE-template has to be used. To get rid of the question if the domain is correct you can provide the domain with the kernel-options.
For this I would remove the domain from the Debian-only-settings and add the domain to the kernel-parameters.
I tested this with an installation using foreman 2.1.3 and bootdisk 17.0.2 - but I do not see where the change should break things.
I tested the deployment with Ubuntu20.04 and Debian10.