注册中心高可用
理论上来讲,服务消费者本地缓存了服务提供者的地址。即使 Eureka Server 宕机,也不会影响服务之间的调用,但是一旦涉及到服务的上下线,本地的缓存信息将会出现偏差,从而影响到了整个微服务架构的稳定性,因此搭建 Eureka Server 集群来提高整个架构的高可用性,是非常有必要的。这样就可以使注册中心高可用。
搭建Eureka集群
开启 Eureka 集群配置后,服务启动时 Eureka Server 会将注册信息向其它 Eureka Server 进行同步,因此搭建高可用架构只需要将 Eureke Server 配置指向其它可用的 serviceUrl 即可。
我们在上面 Eureka 单个示例的基础上,复制出三份来分别命名为:eureka7001、eureka7002、eureka7003 等多个示例项目,使用多个示例项目搭建 Eureka Server 的集群。
接下来需要分别修改 eureka7001、eureka7002 的配置信息
eureka7001主程序配置:
@SpringBootApplication
@EnableEurekaServer
public class Eureka7001 {
public static void main(String[] args) {
SpringApplication.run(Eureka7001.class,args);
}
}
eureka7001的application.yam配置
server:
port: 7001
eureka:
instance:
hostname: eureka7001.com
client:
register-with-eureka: false
fetch-registry: false
service-url:
defaultZone: http://eureka7002.com:7002/eureka
server:
# 禁用自我保护模式
enable-self-preservation: false
eviction-interval-timer-in-ms: 2000
eureka7001的pom.xml
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<!-- https://mvnrepository.com/artifact/org.springframework.cloud/spring-cloud-starter-netflix-eureka-server -->
<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>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
</dependencies>
eureka7002主程序配置:
@SpringBootApplication
@EnableEurekaServer
public class Eureka7002 {
public static void main(String[] args) {
SpringApplication.run(Eureka7002.class,args);
}
}
eureka7002的application.yml配置:
server:
port: 7002
eureka:
instance:
hostname: eureka7002.com
client:
register-with-eureka: false
fetch-registry: false
service-url:
defaultZone: http://eureka7001.com:7001/eureka
server:
# 禁用自我保护模式
enable-self-preservation: false
eviction-interval-timer-in-ms: 2000
eureka7002的pom.xml
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<!-- https://mvnrepository.com/artifact/org.springframework.cloud/spring-cloud-starter-netflix-eureka-server -->
<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>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
</dependencies>
eureka.client.register-with-eureka和eureka.client.fetch-registry配置为 true ,表示将自己注册到注册中心,并且从注册中心获取注册信息
eureka.client.serviceUrl.defaultZone,指向其它两个注册中心,重点配置内容
测试:依次启动 eureka7001、eureka7002项目,等待全部启动完成之后,浏览器访问地址:eureka7001.com:7001和eureka7002.com:7002
总结:
eureka集群注册就是---》 相互守望、相互注册