I recently had to install a debian encrypted host on a scaleway server. I remember reading about unattended installs using qemu-kvm, but none did fit my setup. Based on this amazing article from Quentin JOLY, I found a suitable and quite elegant way to do things. This setup was tested on a scaleway store-4-M and an OVH VPS-2. As this only requires some space and a qemu capable rescue mode, it should work with most bare metal cloud providers.