Darko Andročec, Neven Vrček

Abstract
Interoperability problems between cloud providers are one of the most serious issues of this new computing paradigm. A methodology is needed to systematically and effectively find and solve interoperability problems. For these reasons, a new methodology with detailed steps to find and solve interoperability problems is proposed here. This new methodology is focused and implemented on the platform as a service model, but it can be used in any of the three main models of cloud computing. The methodology uses an iterative approach, because platform as a service offers and their application programming interfaces evolve and change very often. The focus of the methodology is to use remote cloud application programming interfaces to solve interoperability problems on technical, storage and services levels, respectively. Finally, we show the application of the methodology to achieve service-level interoperability among different providers of platform as a service.
Keywords
cloud interoperability, methodology, ontology, service composition