A promise of cloud computing is the ability to use resources dynamically as needed without having to deal with tasks pertaining to managing the underlying infrastructure. Resources need to be seen in context of the respective service model distinguishing IaaS (Infrastructure as a Service), PaaS (Platform as a Service) and SaaS (Software as a Service). For both IaaS and SaaS, successful solutions exist, that facilitate the dispersion of cloud approaches in practice. PaaS approaches on the other hand are until now less used as the technology is less known and just about to be created. Nevertheless, moving from virtualized hardware to generic cloud platforms offers huge opportunities, because in the PaaS vision arbitrary business applications can profit from cloud properties. Specifically, applications can be executed elasticly based on defineable service level agreements (SLAs) and can adapt to the current situation.
