feat(us-019): distributed tracker consensus — Raft assignments + CRDT gossip
raft.py: minimal Raft consensus for shard-assignment log
- Leader election with random 150–300ms election timeouts
- AppendEntries log replication; majority commit required
- RequestVote RPC with log-completeness check
- Follower registration forwarded to leader via HTTP proxy
gossip.py: LWW CRDT gossip for inference-node heartbeat liveness
- Each tracker keeps {node_id → wall_clock_timestamp}
- Merges incoming gossip by taking max per key
- Pushes snapshot to random peer every 3 seconds
server.py + cli.py:
- TrackerServer gains cluster_peers + cluster_self_url params
- New HTTP endpoints: /v1/raft/vote, /v1/raft/append,
/v1/raft/status, /v1/gossip
- --cluster-peers and --self-url CLI flags
tests/test_tracker_consensus.py: 6 integration tests
- Leader elected within 1s
- Follower registration propagated to all nodes
- Follower proxy to leader
- Leader kill → new election within 5s, registrations continue
- Gossip table updated on heartbeat
92 tests pass, 1 skipped.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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