Memory leak in per-connection cache
You deploy v205 of a Node.js websocket gateway at 09:00. Everything looks fine for ~40 minutes, then pods begin restarting one by one with OOMKilled, and as each restarts, clients reconnect en masse, briefly spiking load on the survivors which then OOM faster — a rolling brownout. The memory dashboard shows each pod's RSS climbing linearly from deploy time, never plateauing. v205 added a per-connection in-memory cache of recent messages. Request rate is flat versus yesterday. 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.