Code RoomAutoscaler removal spiral during ramp
HardPrep Room Coding #2585

Autoscaler removal spiral during ramp

On-callReliability & on-callSenior–Staff~40 min

A morning traffic ramp at 09:00 triggers a cascading collapse instead of a smooth scale-up. Dashboards: as load rose, autoscaler added pods; new pods take ~90s to warm caches/JIT before serving fast; during warm-up they're slow, so the LB's per-pod success rate drops, the LB marks them unhealthy and removes them, which dumps their share of load back onto the already-hot old pods, which then also start failing health checks — a removal spiral. Effective capacity is DROPPING as you add pods. No deploy. 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
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