debootstrap installs a basic Debian system into a directory, for use with chroot(8). vmdeboostrap is a wrapper around it to install Debian into a disk image, which can be used with a virtual machine (such as KVM) or on physical hardware.

vmdb2 is a re-design of vmdebootstrap that is going on right now. It's not ready for real use. But you're welcome to follow, try, give feedback, and help to make it a good tool.