System designHardsd-g212

Subject ConsensusLevel Senior–Staff~45 minCommon in Distributed systems interviewsIndustries Technology, Software development

Question

Design a globally distributed configuration/secrets service (think a control plane for a cloud provider) that must remain available and consistent for writes even if an entire region goes offline, with replicas in 5 regions. Writes are rare but must be durable and ordered; reads are frequent and must reflect the latest committed config. How many replicas and where, what consensus approach, and how do you keep write latency tolerable when a quorum spans continents?

What a strong answer looks like

Clarify scale and constraints first. Propose a clean component breakdown, then go deep on the hard parts — data model, bottlenecks, consistency, failure modes — and name the trade-offs you are making.

Learn the concepts

Narrate your design

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Run or narrate your approach, then ask the coach.