Aeolus is an ANR funded research project whose main objective is to tackle the scientic problems that need to be solved in order to bridge the gap between Infrastructure as a Service and Platform as a Service solutions, by developing theory and tools to automate deployment, reconfiguration, and upgrades of variable sized, non-homogeneous machine pools. We expect that the results of this research work will allow to efficiently deploy, maintain, and administer, in a cost-effective way, the dynamically changing distributed architectures which are at the heart of Cloud services.