Configuration Service — Notes
Functional
- Versioned KV (per env/region).
- Schema validation, approval workflow.
- Watch / push to clients.
- Canary rollout, rollback, audit.
Non-functional
- Push propagation < 5 s.
- High read fan-out.
- Survive registry failure with stale-OK cache.
Trade-offs
- Strong consistency for writes; eventual push to clients with reconcile loop.
- GitOps vs runtime UI: prefer GitOps for prod, UI for ops only.
- Per-tenant secrets live in dedicated vault (KMS, Vault), not the config service.
Refs
- Spring Cloud Config; HashiCorp Consul KV; AWS AppConfig.
- Netflix Archaius (config patterns).
- LaunchDarkly / Optimizely (overlap with feature flags).