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K8s L4 K8S 1474 · 9 min

A CoreDNS negative cache hides a fixed Service because the TTL outlives the rollout that restored the missing endpoint

The Service is healthy again, but pods keep honoring a stale NXDOMAIN response.

K8sPlatform ReliabilityLevel 4Pro9 min
Scenario

A service recovers, yet callers keep failing for several minutes because the negative DNS result is still cached.

What to check first
  • Identify the primary failure signal in the The Service Came Back and DNS Remembered the Moment It Was Missing 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

Inspect negative TTLs before rebuilding the Service or restarting CoreDNS.

Questions worth viewing together
Should I translate commands, logs, or product names?

No. Keep commands, logs, file names, APIs, and product names unchanged, then explain the reasoning in the selected UI language.

What should the answer focus on?

State the root cause, the evidence that supports it, and the safest recovery direction.

Why can the scenario remain in the original language?

The source scenario is treated as an incident artifact. Guidance, checklist, hints, and explanations can be localized around it.