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Control Kubernetes custom metric cardinality before HPA and remote_write lie to you

A practical workflow for exposing useful business metrics without turning Prometheus, autoscaling, and dashboards into a noise factory.

Learn how to design, audit, and roll out Kubernetes custom metric exporters with label budgets, PromQL tests, remote_write guardrails, and HPA validation.

Created: July 25, 2026

Published: July 25, 2026

Estimated time45 min

LevelAdvanced

Before you startRead access to Prometheus and the /api/v1/status/tsdb endpoint.

PlatformsLinux / Docker

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Linux

Audit cardinality, validate rules, and prove HPA consumes fresh metrics before promoting the exporter.

kubectlcurljqpromtool

List custom metrics resources

kubectl get --raw /apis/custom.metrics.k8s.io/v1beta2 | jq '.resources[].name'

Inspect Prometheus series state

curl -s http://prometheus.monitoring:9090/api/v1/status/tsdb | jq '.data.headStats'

Validate rules before rollout

promtool check rules custom-metrics.rules.yaml && promtool test rules custom-metrics.test.yaml

Also available inControlar cardinalidad de métricas custom de Kubernetes antes de que HPA y remote_write mientan

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