1. A system for managing a virtual appliance lifecycle, comprising: a development environment configured to: create a new appliance in response to one or more appliance creation requests; implement one or more changes for the appliance in response to one or more of the appliance creation requests, wherein the one or more changes include adding one or more software components to the appliance and identifying one or more source repositories containing the software components added to the appliance; and create an image description for the appliance, wherein the image description created for the appliance identifies the software components added to the appliance and the source repositories containing the added software components; a build engine configured to: load a first virtual machine contained in a virtual machine pool in response to receiving a build request containing the image description for the appliance, wherein the first virtual machine provides a contained environment for building the image; and build an image for the appliance within the contained build environment, wherein the image is built from the image description; a runtime environment configured to load a second virtual machine contained in the virtual machine pool to provide a contained environment for executing the image, wherein runtime activity in the contained execution environment results in one or more changes to the image; and a virtualization environment configured to deploy the image over a network, wherein the image deployed over the network includes the changes resulting from the runtime activity.