Designing Modular Systems
Internal
Overview
The larger and tightly coupled a system is, the harder it is to change, and the easier it is to break. The alternative is to compose a system from small, simpler pieces. Each piece has a clearly defined interface and it is easy to understand. The component can be tested and deployed in isolation. Microservices fall into this category.
The systems should be designed for modularity. The goal of modularity is to make it easier and safer to make changes to the system. The hope is that, for a well-designed modular system, you can make a change to a component without needing to change other parts of the system. A well-designed modular system performs well on these operational performance metrics.
Designing components is the art of deciding which elements of your system to group together and which to separate.