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Design a Leader Election System

CoordinationHard1:30

You have 90 seconds to verbally explain how you would design a leader election system for a distributed service.

Your system should: - Elect exactly one leader among N nodes - All nodes agree on who the leader is - Automatically re-elect if leader fails - Tolerate network partitions - Prevent split-brain scenarios

Explain your consensus algorithm, failure detection, and state management.

How to approach it

  • Hint 1

    Use Raft or Paxos consensus algorithm to ensure agreement across nodes

  • Hint 2

    Implement heartbeat mechanism for failure detection with quorum-based decisions

  • Hint 3

    Consider term/epoch numbers to detect stale leaders after partition heals

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