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Fix Kubernetes memory alerts without falling for the page cache trap

A practical Prometheus workflow so memory pages fire on RSS, OOMs, and real pressure, not because container_memory_usage_bytes wanted attention.

Learn how to redesign Kubernetes memory saturation alerts by comparing usage, working set, RSS, cache, limits, OOMKilled events, and promtool validation.

Created: August 26, 2026

Published: August 26, 2026

Estimated time40 min

LevelIntermediate

Before you startPrometheus scraping kubelet/cAdvisor and kube-state-metrics

PlatformsLinux / Docker

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Docker

Validate alert rules locally with promtool and synthetic fixtures before changing the real Prometheus server.

Dockerrules.yamltests/*.yaml

Run promtool in a container

docker run --rm -v $PWD:/work -w /work prom/prometheus:latest promtool test rules tests/k8s-memory-alerts.test.yaml

Validate rule syntax

docker run --rm -v $PWD:/work -w /work prom/prometheus:latest promtool check rules rules/k8s-memory-alerts.yaml

Also available inCorregir alertas de memoria en Kubernetes sin caer en la trampa de page cache

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