Deadline not propagated to upstream
A request flows gateway → A → B → C (all gRPC). The gateway sets a 2s deadline. At 20:00, C develops a latency tail (p99.9 ~5s). The gateway times out at 2s and returns errors to users — expected. But you ALSO see C and B CPU climbing and their inbound request rate rising, even though the callers that triggered the work already gave up at 2s. Dashboards: B and C keep processing requests whose gateway deadline has long passed; retries from A add more load. How do you triage and mitigate?
What a strong answer looks like
Stop the bleeding first (mitigate), then form hypotheses from real signals. Separate root cause from symptom, communicate status as you go, and close with what prevents a repeat.
0:00 of about 40 min
Which questions mattered is sealed until you submit. Telling you now would just be handing over the edge cases.
Run or narrate your approach, then ask the coach.