The provisioning of a host computing system by a controller located over a wide area network. The host computing system has power-on code that automatically executes upon powering up, and causes the host to notify the controller of the host address. In a first level of bootstrapping, the controller instructs the host to download a maintenance operating system. The host responds by downloading and installing a maintenance operating system, enabling further bootstrapping. The persistent memory may further have security data, such as a public key, that allows the host computing system to securely identify the source of the download instructions (and subsequent instructions) as originating from the controller. A second level of bootstrapping may accomplish the configuring of the host with a hypervisor and a host agent. A third level of bootstrapping may accomplish the provisioning of virtual machines on the host.