TOSCAMART: A Method for Adapting and Reusing Cloud Applications

The OASIS TOSCA standard defines a language to describe the provisioning and management of cloud applications in a portable and interoperable way. TOSCA enables developers to model cloud applications by specifying their topologies as orchestrations of typed nodes and relationships. However, modelling such application topologies often results in reinventing the wheel multiple times when similar models are created manually for different applications by different developers having the same requirements. Thus, the reusability of existing TOSCA models is of vital importance to enable an efficient, standards-based development process. In this paper, we tackle this issue. We introduce TOSCA-MART, a method that enables deriving valid implementations for custom node types from a repository of complete and validated cloud application topologies. The method enables developers to specify individual node types in their topologies including the desired management operations and properties. TOSCA-MART illustrates how to match, adapt, and reuse existing application topologies to implement these types while fulfilling all their compliance requirements. We validate the proposed method by a prototypical implementation based on an open source toolchain and a case study. In addition, we evaluate its termination, soundness and computational complexity, and prove its practical feasibility by a performance analysis.