Variables and templating

Audience

you have read lesson 01 and you know what legendFormat: "{{route}}" is

Duration

40 to 55 min

Module

4/7

Target skill

add a $route variable fed by label_values(...) to a dashboard, use it in queries with =~, choose between All, multi-value and single value, understand what $__rate_interval really replaces, and repeat a panel per value.

In one picture

Go back to lesson 01's cockpit. The kit's dashboard has 23 frozen dials: Trafic par route (Traffic per route) draws all routes at the same time. A variable (template variable) is a selector placed at the top of the cockpit: you choose /cours in the list, and all dials containing $route recompute for that route alone. Grafana does nothing magical: when sending the query to Prometheus, it replaces the text $route with the chosen value. The rest is PromQL you already know.