Step-by-Step Guide to Building Spring Cloud Microservices with Eureka, Ribbon, and Feign

This article introduces the fundamentals of Spring Cloud, explaining its role in decomposing monolithic applications into independent microservices, likening the architecture to school departments, with Eureka as a registry, Zuul as a gateway, and Hystrix as a circuit breaker.

It provides detailed steps to create a new Spring Boot project in IntelliJ IDEA, configure Maven settings, and add the necessary Spring Cloud dependencies (Spring Cloud Edgware.SR5 and Spring Boot 1.5.7) in the pom.xml for both the Eureka server and client modules.

For the Eureka server, the application.yml is configured with a custom port (e.g., 8700) and disables self‑registration. The server’s entry point EurekaServerApplication.java is annotated with @SpringBootApplication and @EnableEurekaServer, and can be run directly from the IDE.

The client service module includes its own application.yml (port 8701) that points to the Eureka server, and defines a simple REST controller ( Controller) exposing /Hello/World. Its entry point EurekaServiceApplication.java is annotated with @EnableDiscoveryClient.

To consume services, a consumer module is set up with a port (e.g., 8702) and registers with the same Eureka server. The consumer’s ConsumerController demonstrates three invocation methods: direct URL access, using LoadBalancerClient to choose a service instance, and the preferred RestTemplate approach with @LoadBalanced bean configuration.

The article also shows how to add the Ribbon dependency ( spring-cloud-starter-ribbon) and configure the consumer’s application.yml for load‑balanced calls, including a @Bean method that creates a RestTemplate annotated with @LoadBalanced.

For high availability, it details configuring multiple Eureka server instances (ports 8699, 8698, 8697) with replicated application.yml settings, enabling them to share service registries. It demonstrates that even if some servers go down, clients can still discover services thanks to cached service lists, and explains the need to restart consumers to refresh the cache.

Throughout the guide, screenshots illustrate IDE steps, Maven configuration, and console output, reinforcing the practical setup process.