Eureka集群搭建


1、Eureka集群搭建

2、Eureka自我保护机制

Eureka 集群搭建

高可用集群配置

当注册中心扛不住高并发的时候,这时候 要用集群来扛;

普通操作

我们再新建两个module microservice-eureka-server-2002 microservice-eureka-server-2003

pom.xml 把依赖加下

<dependencies>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-eureka-server</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
    <!-- 修改后立即生效,热部署 -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>springloaded</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-devtools</artifactId>
    </dependency>
</dependencies>

2、2002 2003的主启动类EurekaServerApplication_2002,EurekaServerApplication_2003复制修改下;

package com.hmc.microserviceeurekaserver2002;

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

@EnableEurekaServer
@SpringBootApplication
public class MicroserviceEurekaServer2002Application {

    public static void main(String[] args) {
        SpringApplication.run(MicroserviceEurekaServer2002Application.class, args);
    }

}

3、前面单机的时候 eureka注册中心实例名称 是localhost,现在是集群,不能三个实例都是localhost,这里复杂的办法是搞三个虚拟机,麻烦,这里有简单办法,直接配置本机hosts,来实现本机域名映射;

找到 C:\Windows\System32\drivers\etc 打开hosts,加配置

127.0.0.1  eureka2001.hmc.com
127.0.0.1  eureka2002.hmc.com
127.0.0.1  eureka2003.hmc.com

4、修改三个项目的application.yml文件,主要是修改 hostname和defaultZone,

2001修改:

server:
  port: 2001
  context-path: /
eureka:
  instance:
    # 单机 hostname: localhost #eureka注册中心实例名称
    hostname: eureka2001.hmc.com # 集群
  client:
    register-with-eureka: false     #false 由于该应用为注册中心,所以设置为false,代表不向注册中心注册自己。
    service-url:
      defaultZone: http://eureka2002.hmc.com:2002/eureka/,http://eureka2003.hmc.com:2003/eureka/ # 集群
      #单机defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/       #设置与Eureka注册中心交互的地址,查询服务和注册服务用到

2002修改:

server:
  port: 2002
  context-path: /
eureka:
  instance:
    # \u5355\u673A hostname: localhost #eureka\u6CE8\u518C\u4E2D\u5FC3\u5B9E\u4F8B\u540D\u79F0
    hostname: eureka2002.hmc.com # \u96C6\u7FA4
  client:
    register-with-eureka: false     #false \u7531\u4E8E\u8BE5\u5E94\u7528\u4E3A\u6CE8\u518C\u4E2D\u5FC3\uFF0C\u6240\u4EE5\u8BBE\u7F6E\u4E3Afalse,\u4EE3\u8868\u4E0D\u5411\u6CE8\u518C\u4E2D\u5FC3\u6CE8\u518C\u81EA\u5DF1\u3002
    service-url:
      defaultZone: http://eureka2001.hmc.com:2001/eureka/,http://eureka2003.hmc.com:2003/eureka/ # \u96C6\u7FA4
      #\u5355\u673AdefaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/       #\u8BBE\u7F6E\u4E0EEureka\u6CE8\u518C\u4E2D\u5FC3\u4EA4\u4E92\u7684\u5730\u5740\uFF0C\u67E5\u8BE2\u670D\u52A1\u548C\u6CE8\u518C\u670D\u52A1\u7528\u5230

2003修改:

server:
  port: 2003
  context-path: /
eureka:
  instance:
    # \u5355\u673A hostname: localhost #eureka\u6CE8\u518C\u4E2D\u5FC3\u5B9E\u4F8B\u540D\u79F0
    hostname: eureka2003.hmc.com # \u96C6\u7FA4
  client:
    register-with-eureka: false     #false \u7531\u4E8E\u8BE5\u5E94\u7528\u4E3A\u6CE8\u518C\u4E2D\u5FC3\uFF0C\u6240\u4EE5\u8BBE\u7F6E\u4E3Afalse,\u4EE3\u8868\u4E0D\u5411\u6CE8\u518C\u4E2D\u5FC3\u6CE8\u518C\u81EA\u5DF1\u3002
    service-url:
      defaultZone: http://eureka2001.hmc.com:2001/eureka/,http://eureka2002.hmc.com:2002/eureka/ # \u96C6\u7FA4
      #\u5355\u673AdefaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/       #\u8BBE\u7F6E\u4E0EEureka\u6CE8\u518C\u4E2D\u5FC3\u4EA4\u4E92\u7684\u5730\u5740\uFF0C\u67E5\u8BE2\u670D\u52A1\u548C\u6CE8\u518C\u670D\u52A1\u7528\u5230

5、修改服务提供者项目的application.yml,主要修改eureka.client.service-url.defaultZone

eureka:
  instance:
    hostname: localhost  #eureka客户端主机实例名称
    appname: microservice-student  #客户端服务名
    instance-id: microservice-student:1001 #客户端实例名称
    prefer-ip-address: true #显示IP
  client:
    service-url:
      defaultZone: http://localhost:2001/eureka   #把服务注册到eureka注册中心

最后我们测试下:

启动三个注册中心,以及服务提供者项目;

上面eureka服务搭建,除了yml文件不一样,其他文件都一样,那么我们有什么办法能够将多个eureka服务集合到一个工程中去呢?

创建一个microservice-eureka-server(三合一)子工程

Pom依赖

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>com.hmc</groupId>
        <artifactId>springcloud</artifactId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <artifactId>microservice-eureka-server</artifactId>

    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka-server</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <!--  修改后立即生效,热部署  -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>springloaded</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>


</project>

Yml文件

---
server:
  port: 2001
  context-path: /
eureka:
  instance:
   hostname: eureka2001.hmc.com
  client:
    register-with-eureka: false
    service-url:
      defaultZone: http://eureka2002.hmc.com:2002/eureka/,http://eureka2003.hmc.com:2003/eureka/
spring:
  profiles: eureka2001
---
server:
  port: 2002
  context-path: /
eureka:
  instance:
    hostname: eureka2002.hmc.com
  client:
    register-with-eureka: false
    service-url:
      defaultZone: http://eureka2001.hmc.com:2001/eureka/,http://eureka2003.hmc.com:2003/eureka/
spring:
  profiles: eureka2002
---
server:
  port: 2003
  context-path: /
eureka:
  instance:
    hostname: eureka2003.hmc.com
  client:
    register-with-eureka: false
    service-url:
      defaultZone: http://eureka2001.hmc.com:2001/eureka/,http://eureka2002.hmc.com:2002/eureka/
spring:
  profiles: eureka2003

启动类MicroserviceEurekaServerApplication.java

package com.hmc.microserviceeurekaserver;

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

@EnableEurekaServer
@SpringBootApplication
public class MicroserviceEurekaServerApplication {

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

}

Eureka 自我保护机制

开发环境,我们经常会遇到这个红色的警告;

当我们长时间为访问服务以及变更服务实例名称的时候,就会出现这个红色警告;

默认情况,如果服务注册中心再一段时间内没有接收到某个微服务实例的心跳,服务注册中心会注销该实例(默认90秒)。

由于正式环境,经常会有网络故障,网络延迟问题发生,服务和注册中心无法正常通信,此时服务是正常的,不应该注销该服务,Eureka这时候,就通过“自我保护模式”来解决问题,当短时间和服务失去通信时,保留服务信息,当恢复网络和通信时候,退出“自我保护模式”;

通过“自我保护模式”,使Eureka集群更加的健壮和稳定;


原文链接:https://www.cnblogs.com/xmf3628/p/11999956.html


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