You want to expose some configuration of the subsystem or "runtime metrics" of the deployment itself?
I would guess the later.
First thing you need to do is register "deployment model" under which you define resource(and subresources) and what attributes it has.
than you need just to implement the read attribute handlers for each attribute.
Usually such read attribute handler will lookup the (msc) service which holds the information you want to expose.
This service you can add as part of DUP you are already writing.
then in cli you will be able to access this data under
and example of such deployment resource would be servlets info exposed via undertow subsystem see
hope this is what you are looking for, otherwise do explain what exactly you want to do.
indeed, I'm more talking about runtime-metrics.
What I was missing is that I can indeed install a service through a DUP, as shown in the UndertowDeploymentProcessor. That processor should get me on my way to implement what I need.