Article author here. Basically we forked the latest Prometheus and embedded the golang OpenZiti SDK into the server to allow listening and dialing over the overlay network.

Find that code at https://github.com/openziti-test-kitchen/prometheus/tree/fea.... It's not a lot of code that I had to add to make this happen. Happy to answer questions on how that sdk works if there's interest.

3 part series:

Part 1 - background

Part 2 - get your hands dirty

Part 3 - use the resultant Prometheus solution