Monitoring application performance in production is important for staying ahead of customer reported issues. The prom_ex library helps expose key metrics (and custom ones too). But you need a Prometheus compatible system to gather and aggregate those metrics. Then Grafana can make it pretty to look at and see trends. Alex Koutmos, author of prom_ex, shows how to do that on the Fly.io platform using Fly’s built-in Prometheus metrics gathering and goes further showing how to get that data into Grafana.

I’ve set this up myself before in a Kubernetes cluster… but I’ve got to say, this is waaaaay easier!

https://fly.io/blog/monitoring-your-fly-io-apps-with-prometheus/