In recent years, we've seen many advances from typical imperative configuration of Linux distributions to more sophisticated declarative configuration systems. NixOS takes a different path to achieve declarative configuration than current widely used state-of-art configuration management systems. By redefining how we package software today using Nix package manager, Linux distribution is configured stateless without examining current state of configuration on the machine. During the talk, we'll be looking at concepts behind NixOS stack and I'll show some real world examples of usage