Cloud computing patterns can be used to build cloud applications based on proven and tested solutions. However, the correct implementation of these patterns is not always warranted during the whole life cycle of an application. Inconsistencies between implementation and cloud computing patterns can result in architectural drift and negatively impact the quality attributes of an application. Therefore, this thesis presents a method to check the consistency of cloud computing patterns at runtime. Nine cloud computing patterns are selected and analyzed in detail for structural and semantic constraints. A formal notation is developed to express the constraints and enable automatic consistency checking of the patterns. Furthermore, a framework is designed which enables monitoring of cloud applications and checking of constraints for cloud computing patterns at runtime. To show the feasibility of this method, the framework is implemented and successfully tested in a cloud computing environment, with a simulated workload on virtual machines, for the patterns Static Workload, Continuously Changing Workload, Elasticity Manager, and Watchdog.