Finding available services in TOSCA-compliant clouds

The OASIS TOSCA specification aims at enhancing the portability of cloud applications by defining a language to describe and manage them across heterogeneous clouds. A service template is defined as an orchestration of typed nodes, which can be instantiated by matching other service templates. In this paper, we define and implement the notions of exact and plug-in matching between TOSCA service templates and node types. We then define two other types of matching (flexible and white-box), each permitting to ignore larger sets of non-relevant syntactic differences when type-checking service templates with respect to node types. The paper also describes how a service template S that plug-in, flexibly, or white-box matches a node type N can be suitably adapted so as to exactly match N.