Unixcop published a tutorial about running a VM headless in QEMU-KVM.

How to run a VM headless in QEMU-KVM

A client asked me to find a way to keep running an ancient system (from 10+ years ago) in a new server. The old binary packages didn’t work. I couldn’t even compile those packages for our linux in the new server. Then I though in create a Virtual Machine. 

How to run a VM headless in QEMU-KVM - Unix / Linux the admins Tutorials