Connection churn from sidecar keepalive misconfiguration
After a service-mesh sidecar upgrade, p99 latency on an internal service-to-service call (gRPC over HTTP/2, mTLS) regressed from 8ms to 45ms, while p50 is unchanged. CPU on both client and server pods rose. Connection-level metrics show the count of new TCP connections + TLS handshakes per second jumped roughly 20x after the upgrade; the per-connection request count dropped to ~1. The mesh config that changed touched connection idle-timeout / keepalive settings. Triage and explain why p99 specifically suffered.
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 40 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.