- This option allows the user to select the interface type for the CDROM drive, e.g. `virtio-scsi`, rather than the default `virtio` - Background: Installation of Ubuntu 20.04 on ARM64 fails as it can't mount the installation CDROM. While the default `virtio` CDROM fails, setting `cdrom_interface: virtio-scsi` with this PR succeeds. Some links: - ISO link: http://cdimage.ubuntu.com/ubuntu-legacy-server/releases/20.04/release/ubuntu-20.04-legacy-server-arm64.iso - https://bugs.launchpad.net/ubuntu/+source/debian-installer/+bug/1605407 - https://superuser.com/a/1376628/230508