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K8s L6 K8S 1323 · 15 min

An HPA sees no metrics after a label cleanup because the metrics adapter cache still serves discovery data for the old label set while the new selector never becomes visible

The workload is healthy, yet scaling stops because the adapter did not refresh the metric discovery contract after a label schema change.

K8sPlatform ReliabilityLevel 6Pro15 min
Scenario

A platform team standardizes labels and later an HPA stops seeing metrics even though the backing monitoring query still returns data.

What to check first
  • Identify the primary failure signal in the The Metric Name Stayed the Same but Discovery Still Remembered the Old Labels scenario.
  • Separate visible symptoms from the underlying technical dependency.
  • Describe the safest recovery path and the follow-up prevention work.
Checking checklist
  1. Summarize the current impact and the last known change.
  2. Collect direct evidence from logs, runtime state, and configuration before changing anything.
  3. Separate immediate recovery from permanent prevention work.
Recovery and prevention

Compare adapter discovery output and selector assumptions before rewriting the HPA object.

Questions worth viewing together
What should you verify first when An HPA sees no metrics appears?

Community-field Kubernetes problem inspired by scaling discussions where metrics adapter discovery stayed stale after a label cleanup. Autoscaling failures often come from stale metric discovery metadata, not from the metric source itself.

What usually causes An HPA sees no metrics in production?

Teams often blame Prometheus when the adapter cache is still advertising the old label contract.

What should you document after resolving An HPA sees no metrics?

Metrics adapters need explicit refresh validation after relabeling efforts.