Code Room
On-callMediumoc-p052
Subject Incident responseLevel Mid–Senior~20 minCommon in Reliability & on-call interviewsIndustries Technology, Software development

Question

A change passed all CI tests but fails in production. What kinds of differences cause this and how do you proceed?

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.

Diagram & narrate the incident
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Run or narrate your approach, then ask the coach.