Cloud computing is an evolving data processing technique.  Cloud computing has been described in a number of documents including, for example, a document published by the National Institute of Standards and Technology (NIST), “The NIST Definition of Cloud Computing”, Peter Mell, Timothy Grance, NIST Special Publication 800-145, September 2011. 
So-called automatic scaling or “auto-scaling” allows users to scale their virtual data processing instances automatically.  At least one cloud service provider offers a capability to users via a web service to launch or terminate compute instances.  Scaling involves adding or removing servers in an infrastructure environment (horizontal) or may include adding or removing resources to an existing server (vertical). 
However, existing approaches to accomplish auto-scaling consider only one cloud environment.  These existing approaches thus limit and constrain the elasticity of the cloud concept.