Availability and High Availability

QNSI is designed for high availability across all tiers.

Availability targets

Component	Target	Notes
Edge gateway	99.99%	Multi-AZ, health-based routing
Auth service	99.9%	Stateless, horizontally scaled
KMS service	99.9%	HSM-backed, cached operations
Storage service	99.9%	Replicated storage backend

HA architecture

Stateless services

• Multiple replicas per service
• Load balancer distributes traffic
• Any replica can handle any request

Stateful components

• Database: Multi-AZ with automatic failover
• HSM: Clustered with replication
• Cache: Redis cluster mode

Health checks

All services expose health endpoints through edge-gateway:

• GET /proxy/<service>/health - basic liveness
• GET /edge/<service>/health - alternative health path

Health check endpoints (GET/HEAD) bypass bot protection and rate limiting for reliable monitoring.

Failover

• Automatic failover within region
• Cross-region failover requires failover-region add-on
• RTO: < 5 minutes (within region)
• RPO: 0 (synchronous replication)