Quiz: Debugging Methodology¶
4 questions
L0 (1 questions)¶
1. What are the five steps of the scientific method applied to debugging?
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1. Observe — identify actual symptoms, not assumptions.2. Hypothesize — generate multiple possible causes.
3. Predict — if hypothesis X is true, what else should be true?
4. Test — check the prediction, changing one variable at a time.
5. Conclude — confirmed or eliminated? Repeat until root cause found.
L1 (1 questions)¶
1. Explain the divide-and-conquer approach to debugging a request that fails between a client and a database through 6 components.
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Test the midpoint of the request path first. If the midpoint works, the problem is between the client and the midpoint. If it fails, the problem is between the midpoint and the database. Continue bisecting the remaining half. This is binary search applied to infrastructure — for a 6-component pipeline, you need at most 3 tests instead of 6.L2 (1 questions)¶
1. A service started failing at 14:00 and a deployment happened at 13:55. How do you determine if the deployment caused the failure vs mere correlation?
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Three tests for causation:1. Revert the deployment — if the problem goes away, strong evidence of causation.
2. Reproduce in isolation — can you trigger the failure by making only that change in staging?
3. Explain the mechanism — trace step by step from the change to the symptom. Also check for other events at 14:00: certificate expiry, traffic spikes, cronjobs, or upstream deploys.
L3 (1 questions)¶
1. Explain the Five Whys technique and why stopping at the first 'why' is insufficient.