Exemplars aren't actually enabled in Mimir

[hedss]

In the docs we have a section to explore traces using exemplars: https://github.com/grafana/tns#explore-metrics-to-traces-to-logs

However, we don't actually enable exemplars in the Mimir configuration. You can verify this by deploying the TNS app and dependencies and then attempting to use exemplars, they will be missing from the metrics panels.

Rewriting the running config, adding:

limits:
  max_global_exemplars_per_user: 100000

and then restarting the pod will enable exemplars. This should be added to the config file here: https://github.com/grafana/tns/blob/main/production/mimir/configmap.libsonnet (and potentially the configs used in the Docker Compose setup, have not checked).

See also: https://grafana.com/docs/mimir/latest/operators-guide/use-exemplars/storing-exemplars/#enable-exemplars-globally

[yves-chan]

Thanks, this worked for me