1. A method of reporting operating states for pluralities of virtual machines to a management server, the pluralities of virtual machines executing on respective compute servers coupled to the management server by a network, the pluralities of virtual machines being managed by respective agents executing on the respective physical compute servers, each operating state having a respective predetermined next operating state according to a predetermined state flow description of creation, use, and destruction of a virtual machine, the method comprising the steps, performed by each of the agents for the corresponding plurality of virtual machines managed by the agent, of: obtaining and locally storing, for each of the virtual machines managed by the agent, first state information indicating a first operating state for the respective virtual machine; and subsequently, during each of a plurality of successive sync intervals: obtaining, for each of the virtual machines managed by the agent, second state information indicating a second operating state for the respective virtual machine; determining, for each of the virtual machines managed by the agent, whether the second operating state of the virtual machine differs is a changed state differing from the first operating state of the virtual machine; responsive to the determining indicating that the second operating state of the virtual machine is a changed state differing from the first operating state of the virtual machine, storing the second operating state for the virtual machine as a respective delta state; and transmitting updated state information to the management server, the updated state information including only the delta states for the virtual machines having changed states and excluding the first state information for the virtual machines not having changed states.