1. A system comprising: physical resources; and one or more virtual overlay infrastructures comprising virtual machines mapped onto the physical resources, wherein each of the one or more virtual overlay infrastructures comprises an infrastructure controller that is implemented by one or more virtual machines, and wherein the infrastructure controller for each of the one or more virtual overlay infrastructures includes, a user accessible part to allow a user of a respective virtual overlay infrastructure to request for a configuration of the respective virtual overlay infrastructure, and a user inaccessible part to prevent the user from accessing the physical resources and prevent the user from controlling a mapping of the virtual machines in the respective virtual overlay infrastructure onto the physical resources.