“Grid vs Cloud” is the title of an incredible number of recent Web blogs and articles in on-line forums and magazines, where many HPC users express their own opinion on the relationship between the two paradigms [Cloud is simply presented, by its supporters, as an evolution of the grid. Some consider grids and clouds as alternative options to do the same thing in a different way. However, there are very few clouds on which one can build, test, or run compute-intensive applications.