This plugin delegates scheduling decisions to external scheduling service.
This plugin monitors jenkins queue and sends it to external scheduler periodically as well as obtaining job-to-node mapping. It propagates this mapping to Jenkins scheduler.
Plugin is inactive unless URL of external scheduler is provided in global configuration (External scheduler plugin/REST server url). During configuration plugin will try to connect to scheduler and verify the connection.
External scheduler is a REST service deployed on URL accessible to Jenkins. It communicates using JSON encoded messages.