Scenario
Traffic drops only from one node after a service rollout on Cilium.
A Cilium node upgrade finishes and one service path still drops because the BPF lb map kept the retired backend slot
Endpoints are healthy, but one node keeps forwarding to a backend entry removed during rollout.
What to check first
- Identify the primary failure signal in the The Upgrade Landed Cleanly and One Node Kept Dialing the Seat Number That Had Already Been Removed From the Chart 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
Inspect pinned BPF maps before widening retries.
Questions worth viewing together
No. Keep commands, logs, file names, APIs, and product names unchanged, then explain the reasoning in the selected UI language.
State the root cause, the evidence that supports it, and the safest recovery direction.
The source scenario is treated as an incident artifact. Guidance, checklist, hints, and explanations can be localized around it.
Similar cases seen in the field