grafana variables in panel

Question

Could you please explane me what does $instance mean in expression:

100 - (avg by (instance) (irate(node_cpu_seconds_total{mode="idle",instance=~"$instance"}[$interval])) * 100) * ON(instance)

and why i see No data points

but when I change $instance to .* graph was shown.

in prometheus I see than node_cpu_seconds_total return data like this:

✔node_cpu_seconds_total{cpu="1",instance="10.0.97.140:9100",job="node-exporter",mode="idle"}

Thanks.

Answer 1

These are variables coming from the Grafana templating feature.

Two notations exist:

• $variable
• [[variable]]

More information in the Grafana docs: https://grafana.com/docs/reference/templating/

The reason you don't see any values in your example is simple: The variable is not defined as a template variable. If you change it to .* you simply allow any value as a regular expression.