1. A non-transitory computer-readable storage medium having computer-executable instructions stored thereupon which, when executed by a computer, cause the computer to: expose an application programming interface (API) comprising a method for executing a command within a virtual machine (VM) instance, the command being specified in data identifying a list of commands available for execution within the VM instance and identifying program code for performing each of the commands; receive a call to the method for executing the command within the VM instance; and cause a request to execute the command to be transmitted to a software component executing in the VM instance, the software component configured to process the request and cause the command to be executed in the VM instance in response to receiving the request.