A cluster enables node-local DNS for performance and later only certain sidecar-controlled egress calls begin failing.
A service mesh sidecar is injected correctly and egress still fails
Pods look normal, yet external calls die because the actual DNS and egress path the node uses no longer matches the mesh policy model.
Scenario
What to check first
- Identify the primary failure signal in the DNS Optimization Changed the Egress Path the Mesh Expected scenario.
- Separate visible symptoms from the underlying technical dependency.
- Describe the safest recovery path and the follow-up prevention work.
Checking checklist
- Summarize the current impact and the last known change.
- Collect direct evidence from logs, runtime state, and configuration before changing anything.
- Separate immediate recovery from permanent prevention work.
Recovery and prevention
Trace the real resolver and egress path before widening mesh egress policy broadly.
Questions worth viewing together
Community-field Kubernetes problem inspired by Discuss Kubernetes patterns where node-local DNS altered the effective egress path behind a mesh. Sidecar policy debugging should include DNS path changes, not only network ACLs.
Teams often blame mTLS or certificates when name-resolution path changes moved traffic outside the expected policy shape.
DNS optimizations can become part of the service-mesh network contract.
Similar cases seen in the field