Abstract : Since the appearance of distributed computing technology, there has been a significant effort in designing and building the infrastructure needed to tackle the challenges raised by complex scientific applications that require massive computational resources. This increases the awareness to harness the power and flexibility of Clouds that have recently emerged as an alternative to data centers or private clusters. We describe in this chapter an efficient high-level Grid and Cloud framework that allows a smooth transition from clusters and Grids to Clouds. The main lever is the ability to move application infrastructure-specific information away from the code and manage them in a deployment file. An application can thus easily run on a cluster, a grid, or a cloud, or any mix of them without modification.