Mastering Microservices: 19 Mind Maps to Understand Spring Cloud Architecture

This article uses 19 mind maps to describe microservice concepts and architecture, covering what microservices are, architecture evolution, microservice architecture, solutions, Spring Cloud overview, and its main components such as Eureka, Ribbon, Feign, Hystrix, Zuul, Gateway, Config, Bus, OAuth2, and Sleuth.

1. What is Microservice

1.1 Architecture Evolution

Architecture has evolved from monolithic to distributed, to SOA, and finally to microservice architecture.

Monolithic architecture: a single Java Web program without any splitting.

Distributed architecture: each business is a monolith, divided vertically, communicating via APIs.

SOA architecture: service‑oriented architecture where components provide or consume services over network protocols.

1.2 Microservice Architecture

Microservice architecture is an evolution of SOA. Martin Fowler describes microservices as a style that splits a single application into small, independently running services that communicate via lightweight mechanisms (typically HTTP REST), each built around a specific business capability and independently deployable.

There is no precise definition of this architectural style, but it is generally understood as a pattern that advocates dividing a single application into a set of small services, each running in its own process and communicating via lightweight mechanisms such as HTTP RESTful APIs. Each service is built around a specific business capability and can be deployed independently. Services should avoid a unified, centralized management mechanism; instead, each service can choose appropriate languages, tools, and data stores based on its business context.

1.3 Microservice Solutions

The two most popular microservice solutions are Spring Cloud and Dubbo.

2. Spring Cloud Overview

2.0 What is Spring Cloud

Spring Cloud is a Java microservice framework built on Spring Boot, offering rapid development, continuous delivery, and easy deployment. It consists of many components covering all aspects of microservices, driven by the open‑source communities of Spring and Netflix.

2.1 Main Components of Spring Cloud

Eureka

Netflix Eureka is a REST‑based service discovery component, including Eureka Server and Eureka Client.

Ribbon

Ribbon is a load‑balancing component open‑sourced by Netflix.

Feign

Feign is a declarative web service client.

Hystrix

Hystrix provides circuit‑breaker functionality to prevent cascading failures in distributed systems.

Zuul

Zuul is an open‑source gateway solution from Netflix.

Gateway

Spring Cloud Gateway, built on Spring 5, Spring Boot 2, and Project Reactor, offers a simple, effective, and unified API routing management for microservice architectures.

Config

Spring Cloud Config provides client and server support for externalized configuration in distributed environments.

Bus

Spring Cloud Bus makes it easy to set up a message bus.

OAuth2

Spring Cloud OAuth2 can protect microservice systems built with Spring Cloud.

Sleuth

Spring Cloud Sleuth offers distributed tracing capabilities for service chains.

In summary, the article provides an overview of architecture evolution and the basic components of Spring Cloud for building microservices.