We took a similar journey with Prometheus @ Improbable. We found federation to have its limits & wanted a global query view as well as a few other nice features

We took a similar journey with Prometheus @ Improbable. We found federation to have its limits & wanted a global query view as well as a few other nice features: https://improbable.io/games/blog/thanos-prometheus-at-scale https://improbable.io/games/blog/thanos-prometheus-at-scale