Timeout reduction triggers retry storm
An SRE lowers the HTTP client timeout to a downstream auth service from 2s to 200ms via a config push at 16:40 (intended to fail faster). At 16:42 the auth service's request rate triples, its CPU saturates, and the calling API's success rate drops from 99.9% to 88%. The auth service itself didn't change and its p50 latency is 150ms but p99 is 400ms. The client retries failed auth calls up to 3 times. 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 30 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.