Microservice

Microservices are an approach to distributed systems that promote the use of finely grained services that can be changed, deployed, and released independently.

Key Concepts of Microservices

Independent Deployability

Independent deployability is the idea that we can make a change to a microservice, deploy it, and release that change to our users, without having to deploy any other microservices. To ensure independent deployability, we need to make sure our microservices are loosely coupled: we must be able to change one service without having to change anything else. This means we need explicit, well-defined, and stable contracts between services.

Modeled Around a Business Domain

By modeling services around business domains, we can make it easier to roll out new functionality and to recombine microservices in different ways to deliver new functionality to our users.

Owning Their Own State

This gives the microservices the ability to decide what is shared and what is hidden, which allows us to clearly separate functionality that can change freely (our internal implementation) from the functionality that we want to change infrequently (the external contract that the consumers use).

Microservices embrace the concept of information hiding.1 Information hiding means hiding as much information as possible inside a component and exposing as little as possible via external interfaces.