Improving the energy efficiency and sustainability of large-scale distributed systems (e.g. data centres and Clouds) is a key challenge for both academic and industrial organizations. After the success of ExtremeGreen2013 and ExtremeGreen2014 and ExtremeGreen2015 workshops, the Xgreen2017 workshop will focus on scientific and industrial approaches and solutions that provide original solutions in terms of energy savings and energy efficiency. Clean-slate approaches and innovative solutions breaking conventional approaches are welcome. The workshop also welcomes submissions of work-in-progress papers on innovations in energy efficiency of large-scale distributed systems. The authors are also encouraged to provide preliminary results that demonstrate the originality and possible impact of the proposed solutions. Submissions will be reviewed by an international group of experts in distributed systems and energy efficiency.