The emergence of the cloud computing paradigm introduces a number of challenges and opportunities to application and system developers. The multiplication and proliferation of available offerings by cloud service providers, for example, makes the selection of an appropriate solution complex and inefficient. On the other hand, this availability of offerings creates additional possibilities in the way that applications can be engineered or re-engineered to take advantage of e.g. the elastic nature, or the pay per use model of cloud computing. This work proposes a formal framework which allows to explore the possibility space of optimally distributing application components across cloud offerings in an efficient and flexible manner. The proposed approach introduces a set of innovative in their use concepts and demonstrates how this framework can be used in practice by means of a running scenario.

International audienceThe availability of an increasing number of cloud offerings allows for innovative solutions in designing applications for the cloud and in adapting existing ones for this environment. An important ingredient in identifying the optimal distribution of an application in the cloud, potentially across offerings and providers, is a robust topology model that can be used for the automated deployment and management of the application. In order to support this process, in this work we present an application topology language aimed for cloud applications that is generic enough to allow the mapping from other existing languages and comes with a powerful annotation mechanism already built-in. We discuss its supporting environment that we developed and show how it can be used in practice to assist application designers

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Service choreographies are commonly used as the means for enabling inter-organizational collaboration by providing a global view on the message exchange between involved participants. Choreographies are ideal for a number of application domains that are classified under the Collaborative, Dynamic & Complex (CDC) systems area. System users in these application domains require facilities to control the execution of a choreography instance such as suspending, resuming or terminating, and thus actively control its life cycle. We support this requirement by introducing the ChorSystem, a system capable of managing the complete life cycle of choreographies from choreography modeling, through deployment, to execution and monitoring. The performance evaluation of the life cycle operations shows that the ChorSystem introduces an acceptable performance overhead compared to purely script-based scenarios, while gaining the abilities to control the choreography life cycle.

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