Virtualisation is a technique to emulate/simulate a set of servers on a physical box. Virtualisation can be seen as a easy way to have a pool of available server to ease to scale application deployment, to ease deployment or recovery procedure.
But … when you developp is can be use to enhance your application quality, and that’s often forgot.
Imagine 5s, than you can now :
- have a blank server in 5 minutes to build hourly your sever, avoiding side effect of previous installation
- have a server with previous release install to validate deployment procedure
- have a network and a farm of sever that are software … not hardware, and now you can simulate/emulate network outage, network slowdown, server crash not by removing the electric plug, but by sending a shell command, …
- imagine you can crash your server and can restart a new instance of it without waiting somebody switch on your box, …
- imagine you can test load balancing/concurrency with only one physical box …..
Do you start to see the fantastic power of virtualisation to validate your application ? 
