Distributed periodic scheduler
Design a scheduler that runs periodic jobs (cron-like, e.g. "send the 9am digest", "reconcile billing hourly") across a fleet of N identical scheduler nodes for high availability, where each scheduled trigger must fire on exactly one node — double-execution sends duplicate emails or double-charges. Constraints: any node can die, the schedule must keep firing, and a network partition must not cause two nodes to both fire the same tick. Describe how a tick is claimed, how concurrent nodes coordinate, and the duplicate-firing safeguards.
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.
Clarify5:00 left
Estimate5:00 planned
Design15:00 planned
Deep dive12:00 planned
Failure8:00 planned
Which questions mattered is sealed until you submit. Telling you now would just be handing over the edge cases.
Run or narrate your approach, then ask the coach.