Modern Cloud computing environments are rapidly evolving, leading to a growing adoption of dynamic pricing for virtual resources and of speedier deployment tools and to the emergence of hybrid Cloud scenarios. These trends suggest the opportunity to investigate a new generation of Cloud-based IT services, capable of adapting to changes in their operating conditions and deployment environment by dynamically realigning their configuration. This calls for new and more sophisticated management tools, that are capable of atomatically evaluating the performance of alternative configurations for Cloud-based IT services and of identifying the one that aligns better to the objectives defined by the business management.