Fault tolerance is a major concern to guarantee availability of critical services as well as application execution. Traditional approaches for fault tolerance include checkpoint/restart or duplication. However it is also possible to anticipate failures and proactively take action before failures occur in order to minimize failure impact on the system and application execution. This document presents a proactive fault tolerance framework. This framework can use different proactive fault tolerance mechanisms, i.e., migration and pause/unpause. The framework also allows the implementation of new proactive fault tolerance policies thanks to a modular architecture. A first proactive fault tolerance policy has been implemented and preliminary experimentations have been done based on system-level virtualization and compared with results obtained by simulation.