[WIP] Grafana and Prometheus

Work in progress (with @toto)

We have Grafana dashboards here: https://kpi.canonical.com/webteam/?orgId=1

Prometheus is here: http://prometheus.webteam.kpi.internal:9090/graph

wsgi_requests_total will show you requests from all websites.

Queries in Grafana look like:

sum(increase(wsgi_requests_total{app="snapcraft.io", kubernetes_namespace="production"}[5m])) by (status)