Cloud computing offers the possibility to build sophisticated software systems on virtualized infrastructures at a fraction of the cost necessary just a few years ago. Nevertheless, the deployment of such complex systems is a serious issue due to the large number of involved software packages and services, and to their elaborated interdependencies. In this paper we address the challenge of automatizing this complex deployment process. We first formalize it as a planning problem and observe that standard planning tools can effectively solve it only on small and trivial instances. For this reason, we propose an ad hoc planning technique which we validate by means of a prototype implementation able to effectively solve this deployment problem also on instances of realistic size.