The Computer Science discipline, especially in large scale distributed systems like Grids and P2P systems and in high performance computing areas, tends to address issues related to increasingly complex systems, gathering thousands to millions of non trivial components. Theoretical analysis, simulation and even emulation are reaching their limits. Like in other scientific disciplines such as physics, chemistry and life sciences, there is a need to develop, run and maintain generations of scientific instruments for the observation of complex distributed systems running at real scale and under reproducible experimental conditions.