Blue-green cutover causes brief spike
You cut over a JVM trading-data API from the blue environment to green via a 100% load-balancer switch at market open. The instant the switch lands, p99 latency on green spikes to 12s for ~90 seconds, error rate hits 15% (mostly client-side timeouts), then everything settles to normal and stays healthy. Green had been deployed and idle for 30 minutes. CPU on green shows a brief 100% spike correlated with the latency. No code differs between blue and green. 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.