FIG. 8 is a block diagram illustrating a computing system diagram that illustrates one configuration for a service provider environment 800 which may be used to implement the technology described herein. The example service provider environment 800 shown in FIG. 8 may include several physical hosts 802a-e for providing computing resources for hosting applications and services. A physical host 802a-e may be a server computer configured to provide computer resources to host one or more computing instances 804a-e. A computing instance 804a-e may be a virtual machine. As known in the art, a virtual machine is an instance of a software implementation of a machine (i.e., a computer) that executes programs like a physical machine. In the example of computing instances 804a-e, each physical host 802a-e may be configured to execute an instance manager 808a-e capable of executing the computing instances 804a-e. In one example, one or more computing instances 804e may be used to host the communication service 830 described earlier. Instance manager 808a-e may be a hypervisor or another type of program configured to enable the execution of multiple computing instances 804a-e on a single physical host 802a-e, for example.
