Eureka集群

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

1、pom.xml 把依赖加下；

<?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.</modelVersion>

    <parent>

        <groupId>com.jt</groupId>

        <artifactId>microservice</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>

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

package com.jt.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.jt.com

127.0.0.1  eureka2002.jt.com

127.0.0.1  eureka2003.jt.com

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

2001修改：

server:

  port:

  context-path: /

eureka:

  instance:

    hostname: eureka2001.jt.com

  client:

    register-with-eureka: false

    service-url:

      defaultZone: http://eureka2002.jt.com:2002/eureka/,http://eureka2003.jt.com:2003/eureka/ # 集群

2002

server:

  port:

  context-path: /

eureka:

  instance:

    hostname: eureka2002.jt.com

  client:

    register-with-eureka: false

    service-url:

      defaultZone: http://eureka2001.jt.com:2001/eureka/,http://eureka2003.jt.com:2003/eureka/

2003

server:

  port:

  context-path: /

eureka:

  instance:

    hostname: eureka2003.jt.com

  client:

    register-with-eureka: false

    service-url:

      defaultZone: http://eureka2001.jt.com:2001/eureka/,http://eureka2002.jt.com:2002/eureka/

骚操作

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.</modelVersion>

    <parent>

        <groupId>com.jt</groupId>

        <artifactId>microservice</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:

  context-path: /

eureka:

  instance:

    hostname: eureka2001.jt.com

  client:

    register-with-eureka: false

    fetch-registry: false

    service-url:

      defaultZone: http://eureka2002.jt.com:2002/eureka/,http://eureka2003.jt.com:2003/eureka/

spring:

  profiles: eureka2001

---

server:

  port:

  context-path: /

eureka:

  instance:

    hostname: eureka2002.jt.com

  client:

    register-with-eureka: false

    fetch-registry: false

    service-url:

      defaultZone: http://eureka2001.jt.com:2001/eureka/,http://eureka2003.jt.com:2003/eureka/

spring:

  profiles: eureka2002

---

server:

  port:

  context-path: /

eureka:

  instance:

    hostname: eureka2003.jt.com

  client:

    register-with-eureka: false

    fetch-registry: false

    service-url:

      defaultZone: http://eureka2001.jt.com:2001/eureka/,http://eureka2002.jt.com:2002/eureka/

spring:

  profiles: eureka2003

启动类MicroserviceEurekaServerApplication.java

package com.jt.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);

    }

}

跑起来的效果跟普通操作的效果是一致的；

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；

巴特西

Eureka集群

普通操作

骚操作

Eureka自我保护机制

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