The vts module has been updated in recent months to support more granular reporting of request times, but it's had everything we need for a while.
It exposes metrics either as an html page or a json api.
So with vts I can finally replace last instance of haproxy which serves as a core LB between all services (because it has stats).
So with vts I can finally replace last instance of haproxy which serves as a core LB between all services (because it has stats).