Fog computing aims at providing horizontal, system-level, abstractions to distribute computing, storage, control and networking functions closer to the user along a cloud-to-thing continuum. Whilst fog computing is increasingly recognized as the key paradigm at the foundation of Consumer and Industrial Internet of Things (IoT), most of the initiatives on fog computing focus on extending cloud infrastructure. As a consequence, these infrastructures fall short in addressing heterogeneity and resource constraints characteristics of fog computing environments. In this presentation, we (1) explain the requirements of fog computing infrastructure and how they extend well beyond those traditionally addressed by Cloud Computing infrastructures; (2) introduce Eclipse fog∅5, an Open Source fog computing Infrastructure that unifies computing, networking and storage fabrics end-to-end, while addressing the challenges imposed by resource heterogeneity, (3) explain the novel architectural approach adopted by fog∅5 to have a server-less data- centric architecture that is scalable, secure, and highly resilient to failures, (4) demonstrate the use of fog∅5 in some real-world use cases and (5) conclude and reports on future works.