An Environment Management System (EMS) provides on-demand instances of environments for testing hardware and/or software configurations. In various embodiments, the EMS includes a processing engine that handles parsing and execution of commands in a definition file that express the lifecycle of a testing environment. Accordingly, the EMS provides flexibility to end users in the way that environments are configured and deployed. An environment definition file is provided that may contain a standard set of scripts for implementing the lifecycle of the environment, along with any custom logic specific to a user or customer.