Prevent Split Votes Through Term Management - The Elector

      ARCHIVED from builddistributedsystem.com on 2026-04-28
      — URL: https://builddistributedsystem.com/tracks/elector/tasks/task-5-5-split-vote
    

                      TASK
                    

Implementation

Handle split votes where no candidate receives a majority. Candidates increment their term and retry. Proper term management ensures the cluster eventually elects a leader.

Sample Test Cases

Increment term on new electionTimeout: 5000ms

Input

{"src":"c0","dest":"n1","body":{"type":"init","msg_id":1,"node_id":"n1","node_ids":["n1","n2","n3"]}}
{"src":"c0","dest":"n1","body":{"type":"set_term","msg_id":2,"term":1}}
{"src":"c0","dest":"n1","body":{"type":"trigger_election_timeout","msg_id":3}}
{"src":"c0","dest":"n1","body":{"type":"get_state","msg_id":4}}

Expected Output

{"src":"n1","dest":"c0","body":{"type":"init_ok","in_reply_to":1,"msg_id":0}}
{"src":"n1","dest":"c0","body":{"type":"set_term_ok","in_reply_to":2,"msg_id":1}}
{"src":"n1","dest":"c0","body":{"type":"trigger_election_timeout_ok","in_reply_to":3,"msg_id":2}}
{"src":"n1","dest":"c0","body":{"type":"state_reply","in_reply_to":4,"msg_id":3,"state":"candidate","term":2}}

Hints

Hint 1▾

Increment term when starting election

Hint 2▾

Step down if see higher term

Hint 3▾

Retry election on timeout

                      OVERVIEW
                    

Theoretical Hub

Term Management

The term acts as a logical clock. Higher terms always win. When a node sees a higher term, it immediately becomes a follower. This prevents stale leaders from causing inconsistency.

Key Concepts

termsplit voteelection retry

main.py

python

Prevent Split Votes Through Term Management - The Elector | Build Distributed Systems