This document discusses service discovery patterns and considerations. It summarizes different approaches to service discovery including using load balancers, DNS, key-value stores, and service meshes. It also provides a case study of how Kaplan Test Prep moved to a microservices architecture on AWS and used service discovery to reduce costs and improve developer productivity. Specifically, they flipped their system-to-service ratio from 3-1 to 1-15, enabled self-service deployments through CI/CD pipelines, and reduced infrastructure costs by 80% for migrated applications.