ABSTRACT
Cloud Computing has emerged as a model to provide access to large amount of data and computational resources by using simple interfaces. Computing is being transformed to a model consisting of services and they are delivered without regard to where and how services are hosted. The ease of using and configuring resources has made this model widespread and several enterprises now offer Cloud-based services to end users and businesses. Anyway, Cloud Computing is still an emerging architecture, and new providers with different services rise every month. In addition, it is very hard to find a single provider which offers all services needed by end users. For this reason, a way to provide a common access to Cloud services and to discover and use required services in Cloud federations is appealing. This is a problem, since different Cloud systems and vendors have different ways to describe and invoke their services, to 468specify requirements, and to communicate. The mOSAIC project addresses these problems by defining a common ontology and it aims to develop an open-source platform that enables applications to negotiate Cloud services as requested by users. The main problem in defining the mOSAIC ontology is in the heterogeneity of terms used by Clouds vendors, and in the number of standards which refer to Cloud Systems with different terminology. In this work, the mOSAIC Cloud Ontology is described. It has been built by analyzing Cloud standards and proposals. The Ontology has been then refined by introducing individuals from real Cloud systems.
