CPU throttling despite headroom
A latency-sensitive service on Kubernetes shows periodic p99 latency spikes to 2s every few seconds even though node CPU utilization sits at a comfortable 40% and the app's own CPU usage looks low. The container has a CPU limit of '500m'. The 'container_cpu_cfs_throttled_periods' and 'throttled_seconds' metrics are high and correlate exactly with the latency spikes. The service is multithreaded (a thread pool sized to the node's many cores). No deploy; traffic is normal. 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 35 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.