HLD-405·Coordination & IDs
Expert · 2,000 ptsMulti-Tenant Distributed Lock & Lease Coordinator
Design a strongly consistent distributed lock and monotonic fencing-token service backing leader election across thousands of tenant clusters.
Max p99
≤ 85 ms
Availability
≥ 99.5%
Budget
≤ $8,900
Functional Requirements
- FR-1POST /leases/{namespace_id}/acquire — Grants exclusive lock with monotonically increasing fencing token.
- FR-2GET /leases/{namespace_id}/verify — High-QPS lease liveness and fencing-token validation.
- FR-3DELETE /leases/{namespace_id}/acquire — Releases canceled or expired leases/holds atomically and immediately refreshes cached availability.
- FR-4Must never grant split-brain duplicate locks or lose committed leases when a leader node crashes.
Workload Profile
Baseline Heartbeats55,000 Verify Read RPS / 11,000 Lease Write RPS
Rebalance Storm Peak150,000 Read RPS / 32,000 Lease Write RPS
Active Working Set24 GB active lock table & session TTLs
Consistency GateLinearizable fencing tokens + RPO = 0 quorum failover
Consistency Model
Strict linearizable / serializable lease CAS + quorum replication (RPO = 0); stale split-brain reads prohibited.
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