Spring Boot Eureka Server

Spring Boot Eureka Server is a service registry that enables service discovery in a microservices architecture. It allows microservices to register themselves and discover other services dynamically. This guide will walk you through setting up and configuring a Spring Boot Eureka Server.

🌟 Why Use Eureka Server?

• Service Discovery: Automatically register and discover microservices.
• Load Balancing: Enables client-side load balancing with Ribbon.
• Failover Support: Services can find alternative instances if one fails.
• Scalability: Easily scale microservices without manual configuration.
• Spring Cloud Integration: Works seamlessly with Spring Boot applications.

🌟 Prerequisites

Ensure you have the following:

• ☕ Java Development Kit (JDK) 17+
• 📦 Maven or Gradle installed

🛠 Step 1: Add Dependencies

Maven Configuration:

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
</dependency>

Gradle Configuration:

implementation 'org.springframework.cloud:spring-cloud-starter-netflix-eureka-server'

📖 Step 2: Create the Eureka Server Application

• Java
• Kotlin

package com.example.eurekaserver;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;

@SpringBootApplication
@EnableEurekaServer
public class EurekaServerApplication {
    public static void main(String[] args) {
        SpringApplication.run(EurekaServerApplication.class, args);
    }
}

package com.example.eurekaserver

import org.springframework.boot.autoconfigure.SpringBootApplication
import org.springframework.boot.runApplication
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer

@SpringBootApplication
@EnableEurekaServer
class EurekaServerApplication

fun main(args: Array<String>) {
    runApplication<EurekaServerApplication>(*args)
}

🛠 Step 3: Configure the Eureka Server

Create an application.yml file for Eureka Server configuration.

server:
  port: 8761
spring:
  application:
    name: eureka-server
eureka:
  client:
    register-with-eureka: false
    fetch-registry: false
  server:
    wait-time-in-ms-when-sync-empty: 5

Note: The Eureka Server does not register itself.

▶️ Running the Eureka Server

Start the Eureka Server application:

./mvnw spring-boot:run

or using Gradle:

gradle bootRun

Access the Eureka Server dashboard:

http://localhost:8761/

📌 Step 4: Register a Client Application

Add Dependencies

Maven:

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>

Gradle:

implementation 'org.springframework.cloud:spring-cloud-starter-netflix-eureka-client'

Client Application Configuration

In the client's application.yml, add the following:

spring:
  application:
    name: eureka-client
eureka:
  client:
    service-url:
      defaultZone: http://localhost:8761/eureka/

Client Application Code

• Java
• Kotlin

package com.example.eurekaclient;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@SpringBootApplication
@RestController
@RequestMapping("/client")
public class EurekaClientApplication {

    @GetMapping
    public String getClientMessage() {
        return "Hello from Eureka Client!";
    }

    public static void main(String[] args) {
        SpringApplication.run(EurekaClientApplication.class, args);
    }
}

package com.example.eurekaclient

import org.springframework.boot.autoconfigure.SpringBootApplication
import org.springframework.boot.runApplication
import org.springframework.web.bind.annotation.GetMapping
import org.springframework.web.bind.annotation.RequestMapping
import org.springframework.web.bind.annotation.RestController

@SpringBootApplication
@RestController
@RequestMapping("/client")
class EurekaClientApplication {

    @GetMapping
    fun getClientMessage(): String {
        return "Hello from Eureka Client!"
    }
}

fun main(args: Array<String>) {
    runApplication<EurekaClientApplication>(*args)
}

🏃 Running the Client Application

Run the Eureka Client application:

./mvnw spring-boot:run

or using Gradle:

gradle bootRun

Check if the client has registered with Eureka Server by visiting:

http://localhost:8761/

Spring Boot Eureka Server provides a robust service discovery mechanism, enabling microservices to dynamically register and locate each other. This enhances scalability, fault tolerance, and efficient communication between microservices.