Résumé : The move of users and organizations to Cloud computing will become possible when they will be able to exploit their own applications, applications and services provided by cloud providers as well as applications from third party providers in a trustful way on different cloud infrastructures. To reach this goal, standard application formats must be enabled on the cloud to avoid vendor-lockin, and guarantees concerning protection, performance and security supported. This article describes the Contrail VEP component developed by the Contrail project. The VEP component is in charge of managing the whole life cycle of OVF distributed applications under Service Level Agreement rules on different infrastructure providers.