To have a full disk encryption on a cloud VM (choose a size with enough RAM (2GB) and downscale after if needed):
- Use the QEMU console to log on as root
apt-get install grub2 ipxe
reboot
- Quickly select "Network boot" in GRUB menu
- Hit Ctrl-B when said so
- At iPXE prompt, type: "chain --autofree http://boot.netboot.xyz"
- Select the Os of choice to install and enable full disk encryption