SpringCloud Eureka集群
简单的SpringCloud的Eureka集群过程:
主要是Eureka的相互注册和服务向各个Eureka服务中心注册服务
首先创建一个Eureka服务端
pom.xml:
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.3.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.example</groupId>
<artifactId>eureka-discovery</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>eureka-discovery</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
<spring-cloud.version>Greenwich.RELEASE</spring-cloud.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>${spring-cloud.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
<repositories>
<repository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/milestone</url>
</repository>
</repositories>
</project>
启动类EurekaDiscoveryApplication.java:
package com.example.eurekadiscovery;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;
@SpringBootApplication
@EnableEurekaServer //该注解必须,标注是Eureka服务中心
public class EurekaDiscoveryApplication {
public static void main(String[] args) {
SpringApplication.run(EurekaDiscoveryApplication.class, args);
}
}
配置application.yml
spring:
application:
name: eureka
eureka:
client:
service-url:
defaultZone: http://localhost:8761/eureka/,http://localhost:8762/eureka/ #向自己注册服务,然后两个服务中心相互注册
注:两个服务中心的代码一致,配置文件一致,发布地址不一致,将defaultZone地址改掉即可。
发布一个Eureka客户端,向Eureka注册信息:
pom.xml:
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.3.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.example</groupId>
<artifactId>order</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>order</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
<version>2.0.0.RELEASE</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
启动类OrderApplication.java:
package com.example.order;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
@SpringBootApplication
@EnableEurekaClient
public class OrderApplication {
public static void main(String[] args) {
SpringApplication.run(OrderApplication.class, args);
}
}
application.yml
spring:
application:
name: order
eureka:
client:
service-url:
defaultZone: http://localhost:8761/eureka/
#此处将所有服务中心的地址都配置进来,用逗号隔开,当某一服务中心宕机,保证该服务的正常调用
#如果只写其中一个服务中心的地址,会向该服务中心进行注册,服务中心之间的复制会将该服务信息复制到其他的服务中心
调用order的代码可在前面的SpringCloud集成的帖子中找到。
客户端代码中只向其中一个Eureka服务中心注册,但是两个服务中心通过同步,另一个Eureka服务中心也存在了order的信息,但是如果order注册的Eureka服务中心宕机,必然导致order无法注册,也将无法同步到其他的服务中心,导致服务不可用,所以客户端服务向Eureka服务中心注册时,需要将所有的Eureka地址写入到application配置中,以保证某一个服务中心宕机是,服务依然能正常提供服务。