Flexible Clusters for High-Performance Computing

High Performance Computational Clusters are, in general, rather rigid objects that present to their user a limited number of degrees of freedom related, usually, only to the specification of the resources requested and to the selection of specific applications and libraries. While in standard production environments this is reasonable and actually desirable, it can become an hindrance when one needs a dynamic and flexible computational environment, for instance for experiments and evaluation, where very different computational approaches, e.g., map-reduce, standard parallel jobs and virtual HPC clusters need to coexist on the same physical facility. In this paper we will present our efforts to address some of these challenges while maintaining a unified cluster management environment.