Setting up a simple map routing server

You need to set up a simple map routing server. The associated costs should be minimized and after setting it up maintaining and modifications should be simple.
Preferably the server would run in the cloud, possibly free for small map (memory) instances.
You can use existing open source software (preferrably java), e.g. GraphHopper, OpenTripPlanner, source by Michael Tandy, etc.. It has to include implementation of ContractionHierarchies.
It has to be able to use at least OpenStreetMap and DIMACS formats of road networks.
It should work on small maps, e.g. one country, but also be able to scale - world-wide routing.
You need to set it u and transfer all the credentials and tools for maintaining and modifying it.