Adapter does not react to its config changes

[eero-t]

What happened?:

Changed prometheus-adapter (custom metrics configMap) config.

Geneated custom metrics did not change until adapter was restarted (by deleting its pod).

What did you expect to happen?:

Similarly to Prometheus, adapter has config-reloader to handle config changes:

$ kubectl -n monitoring get statefulset/prometheus-prom-kube-prometheus-stack-prometheus -o json | jq .spec.template.spec.containers[].name
"prometheus"
"config-reloader"
$ kubectl -n monitoring get deployment/prom-adapter-prometheus-adapter -o json | jq .spec.template.spec.containers[].name
"prometheus-adapter"

Anything else we need to know?:

Currently handling any automation related to custom metrics is really frustrating. Making that reasonable would require both automatic config reloading, and some prometheus-operator support (prometheus-operator/kube-prometheus#2504).

Environment:

• prometheus-adapter version: v0.12.0
• prometheus version: v2.54.0
• Kubernetes version (use kubectl version): 1.30

[k8s-ci-robot]

This issue is currently awaiting triage.

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[dgrisonnet]

It is expected, prometheus-adapter doesn't support automatic config reloading.