Is Eucalyptus a precise implementation of Amazons EC2?
No. Eucalyptus supports Amazon’s interface syntactically and it implements the same functionality (with a few exceptions), but internally it is almost certainly different. Eucalyptus is designed to be extensible and easy to install and maintain, particularly in a research environment, where system administrator time is the most expensive commodity. While we can’t be certain, Amazon’s main design goal almost has to be scalability. Put another way, if we were to design a commercial software venue for cloud services where scalability is paramount and we could mandate how all clusters within the cloud were initially configured (instead of an open-source software tool for community distribution) we would have designed Eucalyptus differently.