Upstream scale-in closes pooled connections
Your service holds a pool of long-lived keepalive HTTP/2 connections to an upstream behind a load balancer. At 02:30 the upstream fleet was scaled in (some instances removed) by an autoscaler. Right after, your service starts seeing ~5% of requests fail with connection resets / 'broken pipe' / timeouts, and it slowly self-heals over ~10 minutes. Dashboards: the upstream is healthy and underloaded; the failing requests all reuse existing pooled connections; brand-new connections always succeed. No deploy on your side. How do you 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 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.