Exploiting Semantics and Patterns for Verification of Orchestrated Cloud Services

Some time passed since the first definitions of Cloud architectures. During the years Cloud systems became more and more complex. The main idea is that all Cloud components offer their functions as a service. For this reason Cloud systems inherits many features from old Web Services and Service Oriented architectures. At the moment, the need for composition and automation of Cloud services is a hot research field. Orchestration is one of the topics that researchers are investigating. Unlike web services, it is not clear what orchestration means in Cloud Systems. It usually addresses automation, but no clear definitions and languages have been provided. Another hot topic regarding composition of cloud services is the definition of design, architectural and communication Patterns for solving well known and common problems. In this work we will show how Orchestration and some Patterns are tightly coupled. We will describe a methodology for definition of orchestrated workflows which exploits some common Cloud Design Patterns in order to verify composition soundness. In addition we will show how this methodology can be used to verify some requirements on the composed Cloud services. The whole methodology is based both on formal semantics definition of an Orchestration language, and on the use of Ontologies for the description of Cloud services interactions.