Auto-Scaling
You scale up or down whenever you need it automatically. This regards hardware requirements etc. You write a function that floats around on the internet and when a parameter is met the function is activated and does its purpose. That function could be "If the hard drive is 85% full then, load up another hard drive" or "If processing is at 80% power then, load up another CPU" Auto scaling is just like elasticity which is the ability to expand and shrink but auto-scaling is automatic.