With the increasing demand for cloud computing services and rapid development and advances in data center techniques, cloud computing is moving from small data centers towards a large scale, highly efficient new computing infrastructure with low cost. The proposed CleanSky network is intended to provide a stimulating and structured platform for the training of young researchers, for the development of innovative ideas and key concepts in the strategic emerging area of cloud computing: data center evolution, consolidation and service migration associated with the “eco-system” of cloud computing.The centric objective of CleanSky is to embed a pool of postgraduates and young researchers in a multidisciplinary, international and intersectoral environment of research activities aiming at developing innovative methodologies and approaches (1) to satisfy application requirements and ensure efficiency within the emerging cloud computing paradigm, and (2) to optimize the energy and provisioning costs of individual data centers, (3) to consolidate, when necessary, multiple data centers through service migration and cloud resource pooling, and (4) to exploit renewable energy sources in cloud data centers.The development of this multidisciplinary training programme, reaching beyond any existing postgraduate programme in the field of cloud computing systems, brings together the academic competence and industrial know-how in multiple disciplines (computer systems, communications, scientific computing, performance engineering, optimization theory and technological economics) that are needed to address the technical and scientific foundation behind the evolution of cloud computing “eco-system”. By establishing structured training for young researchers, the CleanSky is intended to not only shape high-level academic researchers, but also educate next generation experts and innovators with industry mindset for the European industry.