How to install headless Ubuntu using kvm and CLI

Summary While trying to create a new VM using KVM I kind of found it more difficult than expected, so here is a short tutorial on how I finally made it :) This tutorial shows how to create a VM using KVM from the command line. The VM will be running a minimal Ubuntu 18.04 installation without a desktop environment. The whole process can be performed through ssh, so there is no need for openning any windows.