Microservices: Up and Running

Chapter 4. Rightsizing Your Microservices: Finding Service Boundaries

One of the most challenging aspects of building a successful microservices system is the identification of proper microservice boundaries. It makes intuitive sense that breaking up a large codebase into smaller, simpler, more loosely coupled parts improves maintainability, but how do we decide where and how to split the code into parts to achieve those desired properties? What rules do we use to know where one service ends and another one starts? Answering these fundamental questions is challenging. A lot of teams new to microservices stumble at them. Drawing the microservice boundaries incorrectly can significantly diminish the benefits of using microservices, or in some cases even derail the entire effort. It is then not surprising that the most frequent, most pressing question microservices practitioners ask is: how can a bigger application be properly sliced into a collection of microservices?

In this chapter, we look deep into the leading methodology for the effective analysis, modeling, and decomposition of large domains (Domain-Driven Design), explain the efficiency benefits of using Event Storming for domain analysis, and close by introducing the Universal Sizing Formula, a unique guidance for the effective sizing of microservices.

Why Boundaries Matter, When They Matter, and How to Find Them

Right in the title of the architectural pattern, we have the word micro—the architecture we are designing is ...