Partition count limits consumer scaling
Your event-processing service consumes a Kafka topic with 8 partitions via a consumer group. After a customer onboarding tripled event volume, consumer lag grows steadily and processing falls behind SLA. You scaled the consumer deployment from 8 to 24 pods to catch up, but lag kept growing and 16 of the 24 pods sit idle consuming nothing. CPU on the 8 active pods is high. There was no code change. How do you triage and what's the durable fix?
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 28 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.