In the world of computing, one major statement has always been true: the request for computing power is always greater than the available resources. For this reason, scientists and researchers started considering the concept of sharing resources. In the last decade, the world of computing has seen a big leap forward with the emergence of cloud computing. In this new paradigm, computing resources of data centers spread all over the world can be shared to provide increased power and availability to users. However, with this increase in computing power came along an exponential increase in energy ...