The federation of authority in global public computing systems poses major 
resource management challenges, as different stakeholders may have different 
views on how server resources are to be apportioned. Ultimately, the 
complexity of declaring and managing potentially overlapping federated 
policies often leads to the absence of high-level resource management systems 
from global public computing platforms. In this paper we propose a practical 
system that allows the different stakeholders to independently express 
federated policies, provides mechanisms for resolving potential constraint 
overlaps automatically, and reaches decentralised resource 
allocation decisions. We demonstrate experimentally that the system scales 
gracefully, introduces only a very low performance overhead, and is suitable 
for operating in realistically large and complex settings.