A customizer autonomically customizes a virtual appliance by retrieving customization values for various customizable properties of a virtual machine from various providers to customize the virtual appliance in order to simplify deployment of the virtual appliance. The customization properties may include CPU properties, memory properties, storage properties, network properties and properties specific to the software in the virtual appliance. The customizer allows an end user to initiate autonomic customization of the virtual appliance at various times prior to deployment of the virtual appliance. The customizer also allows the user to provide additional customization upon execution.