Service Discovery
Problem
Service A needs Service B.
But B runs as ten dynamic instances whose addresses constantly change.
Hardcoding addresses doesn't work.
Solution — Service Discovery
Maintain a mechanism that maps a logical service identity to currently available instances.
payment-service
↓
10.0.1.7
10.0.2.9
10.0.3.4
Core idea: service discovery separates stable service identity from changing network locations.