title: Use Reserved instance and autoscaling group
body: <p>I would like to know if it would possible to create an architecture with both reserved instance (RI) and auto-scaling group to serve web pages.
  The idea would be to have one RI serving 24/7 and launching on demand instances in an auto-scaling group when the CPU of the RI reach a threshold.
  The goal is to have a predictable cost (RI) and scale out solution with auto-scaling.
  Does it make sens ? Is it Possible ? </p>
  
  <p>Thank you !</p>