[stefanha]

virt-builder is an alternative to installing a guest OS from scratch. It has a selection of popular guest OSes template images that you can quickly install non-interactively.

It's convenient when you don't want to manually install a guest and also don't want to figure out preseed/kickstart/etc.

It makes creating new KVM guests easier and has handy features like the ability to copy in ssh keys so you can connect to the guest right away.

[rlpb]

I think this is a backwards way to set up VMs. "Installing a guest" is the wrong concept. Use a VM image pre-prepared from your favourite distro to skip that step. cloud-init is the standard way for it to specialize to your use case.