What are microservices?
Microservices - also known as the microservice architecture - is an architectural style that structures an application as a collection of services that are: Independently deployable Loosely coupled Services are typically organized around business capabilities. Each service is often owned by a single, small team. The microservice architecture enables an organization to deliver large, complex applications rapidly, frequently, reliably and sustainably - a necessity for competing and winning in today’s world.
Enabling rapid, frequent and reliable software delivery
In order to thrive in today’s volatile, uncertain, complex and ambiguous world, businesses must be nimble, agile and innovate faster. Moreover, since modern businesses are powered by software, IT must deliver that software rapidly, frequently and reliably - as measured by the DORA metrics. Rapid, frequent, reliable and sustainable delivery requires the success triangle, a combination of three things: Process - DevOps as defined by the DevOps handbook Organization - a network of small, loosely coupled, cross-functional teams Architecture - a loosely coupled, testable and deployable architecture Teams work independently most of the time to produce a stream of small, frequent changes that are tested by an automated deployment pipeline and deployed into production. Let’s now look at when you typically need to use microservices in order to have a loosely coupled, testable and deployable architecture.
When you outgrow your monolithic architecture
Let’s imagine that you responsible for a business critical business application that has a monolithic architecture and you are struggling to meet the needs of the business. Should you consider migrating to a microservice architecture? The short answer is that it depends. It’s important to make the most of your monolithic architecture, e.g. adopt DevOps, and reorganize into loosely coupled, small teams. In many cases, once you have embraced the success triangle, your monolithic architecture is sufficiently loosely coupled, testable and deployable to enable rapid software delivery. But sometimes an application can outgrow its monolithic architecture and become an obstacle to rapid, frequent and reliable software delivery. This typically happens when the application becomes large and complex and is developed by many teams. For example, its deployment pipeline become a bottleneck. When this occurs, you should consider migrating to microservices. My presentation Considering Migrating a Monolith to Microservices? A Dark Energy, Dark Matter Perspective describes how to decide whether to migrate to microservices. If you have decided to migrate to microservices then the next step is to design a target architecture.
