Top 4 Error budget Interview Questions
Browse 4 real-world technical and behavioral interview questions about Error budget. Review scenarios, edge cases, and architectural best practices.
The business says the system must be highly available. How do you turn that into a number, and what does that number cost?
Convert the phrase into an error budget over a stated window, derived from what an outage costs the business rather than from a round number of nines. Each additional nine roughly multiplies cost, because it forces redundancy, cross-region failover and operational maturity that the previous nine did not need.
You want to prove the system survives losing a database, in production, on a Tuesday afternoon. How do you run that without being fired?
Turn it into an experiment: a steady state you can measure in under a minute, a blast radius you chose, an abort that is one command with a named person who can call it, and written approval from whoever owns the revenue. Tuesday afternoon is the right time because everyone who understands the system is awake, and the announcement goes to the channel your own alerts land in.
How would you set an SLO for a service, and what is an error budget for?
An SLO defines the reliability users should experience, and the error budget is the allowed gap between that target and perfection. Use burn rate to decide when reliability work must outrank feature delivery.
You promise 99.9 percent availability and you call five services that each promise the same. What have you committed to?
Nines only mean something as a downtime budget over a stated window, and dependencies in series multiply: five hard dependencies at three nines each put your own ceiling near 99.4 percent, so the target is met by removing dependencies from the critical path rather than by asking each owner for more nines.