IAM throttling during instance bootstrap
Your fleet scales out fine on normal days, but at your two highest-traffic peaks each week, scale-up stalls: new instances launch but take 4-8 minutes to become ready instead of 60 seconds, and a fraction never come up. Instance dashboards are clean (no vCPU/IP quota errors). Digging into instance boot logs you find the bootstrap is retrying calls to STS/IAM (`AssumeRole`) and the secrets manager with throttling errors, but only at peak. Your app's runtime traffic doesn't touch those APIs. How do you triage and mitigate the peak-only scale-up failure?
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.