1. A system to provide an external configuration framework, comprising: one or more computing devices; a manifest operable to define a plurality of annotations and their constraints; an application component configurable via the plurality of annotations at build time; a deployment configuration manager operable to configure values of the plurality of annotations under their constraints, and save the values as overrides of the plurality of annotations in an external descriptor at configure or deploy time; a deployment manager operable to distribute, start, stop, or update the application component at runtime; a descriptor framework operable to parse or validate the external descriptor at runtime, wherein a deployment plan is distributed to the descriptor framework in addition to the external descriptor; and a container operable to configure or update the application component externally at runtime with the overrides of the plurality of annotations upon receiving a notification of deployment or deployment change without restarting or redeploying the application component, wherein the container is operable to access the overrides of the plurality of annotations from the descriptor framework, and a custom module operable to: listen to deployment or update event at runtime; respond to the event by invoking the descriptor framework to parse or validate the external descriptor if it is changed; and generate the notification of deployment changes to be delivered to the container.