Service Discovery Patterns in Distributed Systems
Issue #65: System Design Interview Roadmap
The Silent Orchestra Behind Every API Call
When you tap "order" on your food delivery app, dozens of services spring into action behind the scenes. The order service needs to find the payment service, which needs to locate the fraud detection service, which needs to connect to the user profile service. But here's the challenge: these services are constantly moving, scaling up and down, failing and recovering across hundreds of machines in multiple data centers.
How do they find each other in this digital chaos? Welcome to the intricate world of service discovery—the nervous system of distributed architectures that most engineers take for granted until it breaks spectacularly at 2 AM.
The Hidden Complexity Behind "Just Use DNS"
Most textbooks suggest DNS as the solution for service discovery, but production systems reveal a different reality. DNS was designed for relatively static mappings, not for services that can spawn, migrate, or terminate every few seconds. When Netflix's Eureka team analyzed their traffic patterns, they discovered that traditional DNS couldn't handle their service topology changes occurring every 30 seconds during peak traffic.
The fundamental challenge isn't just finding services—it's maintaining a consistent, real-time view of service health, capacity, and locality across thousands of nodes while minimizing the blast radius when things go wrong.