Day17_09_SpringCloud教程之搭建高可用的Eureka注册中心集群

Myth丶恋晨 2024-02-19 20:44 48阅读 0赞

## 搭建高可用的Eureka注册中心集群 ##

### 一. 高可用的服务注册中心集群 ###

#### 1. Eureka高可用概述 ####

考虑到发生故障的情况,服务注册中心发生故障必将会造成整个系统的瘫痪,因此需要保证服务注册中心的高可用.

Eureka Server在设计的时候就考虑了高可用的设计.**在Eureka服务治理设计中,所有节点既是服务的提供方,也是服务的消费方,服务注册中心也不例外.**

#### 2. Eureka高可用原理 ####

**Eureka Server的高可用实际上就是将自己做为服务向其他服务注册中心注册自己,这样就可以形成一组互相注册的服务注册中心,以实现服务清单的互相同步,达到高可用的效果.**

### 二. 构建服务注册中心集群 ###

#### 1. 理论基础 ####

Eureka Server的同步遵循着一个非常简单的原则:

**只要有一条边将节点连接,就可以进行信息的传播与同步.**

**可以采用两两注册的方式实现集群中节点完全对等的效果**,从而实现高可用的集群,这样任何一台注册中心故障都不会影响服务的注册与发现.

#### 2. 实现步骤 ####

本案例创建了3个Eureka Server,采用的是一主两从的模式.我们需要创建3个Eureka Server模块.

如图所示:  
![Image 1][]![2019071417543211.png][]

这3个Eureka Server除了配置文件不同之外,其他的依赖包和代码实现都一样.所以添加依赖包和安全配置类的代码是一样的,不在一一赘述!

#### 2.1 添加依赖包 ####

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

#### 2.2 安全配置类 ####

package com.syc.cloud.config;
    
    import org.springframework.security.config.annotation.web.builders.HttpSecurity;
    import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
    import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
    
    /**
     * Spring Cloud Finchley及更高版本,必须添加如下代码以用来部分关闭掉Spring Security
     * 的CSRF保护功能,否则应用无法正常注册.
     * Spring Cloud Finchley及更高版本必须添加这一段,在Edgware以及更早的版本中无需这一步骤.
     */
    @EnableWebSecurity
    public class WebSecurityConfig extends WebSecurityConfigurerAdapter {
    
        @Override
        protected void configure(HttpSecurity http) throws Exception {
            //忽略掉/eureka/相关接口的安全拦截
            http.csrf()
                    .ignoringAntMatchers("/eureka/**");
            super.configure(http);
        }
    
    }

#### 2.3 创建application.yml文件 ####

#### 2.3.1 eureka\_server01的配置文件 ####

server:
      port: 8761
    spring:
      application:
        name: eurka-server01
      security: #eureka的身份认证
        user:
          name: admin
          password: 123
    
    eureka:
      server:
        enable-self-preservation: true #开启自我保护机制
        renewal-percent-threshold: 0.85 #开启自我保护的阈值
        eviction-interval-timer-in-ms: 5000 #(代表是5秒,单位是毫秒,清理失效服务的间隔)
      instance:
        #instance-id: eureka-server01
        hostname: master
        preferIpAddress: true
        #调整自我保护机制的参数
        lease-renewal-interval-in-seconds: 30
        lease-expiration-duration-in-seconds: 90
      client:
        registerWithEureka: false
        fetchRegistry: false
        serviceUrl:
          #defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/
          #defaultZone: http://admin:123@localhost:8761/eureka/
          defaultZone: http://${spring.security.user.name}:${spring.security.user.password}@slave01:8762/eureka/,http://${spring.security.user.name}:${spring.security.user.password}@slave02:8763/eureka/
          #注意:需要修改host文件配置
          #127.0.0.1 master
          #127.0.0.1 slave01
          #127.0.0.1 slave02

#### 2.3.2 eureka\_server02的配置文件 ####

server:
      port: 8762
    spring:
      application:
        name: eurka-server02
      security: #eureka的身份认证
        user:
          name: admin
          password: 123
    
    eureka:
      server:
        enable-self-preservation: true #开启自我保护机制
        renewal-percent-threshold: 0.85 #开启自我保护的阈值
        eviction-interval-timer-in-ms: 5000 #(代表是5秒,单位是毫秒,清理失效服务的间隔)
      instance:
        #instance-id: eureka-server02
        hostname: slave01
        preferIpAddress: true
        #调整自我保护机制的参数
        lease-renewal-interval-in-seconds: 30
        lease-expiration-duration-in-seconds: 90
      client:
        registerWithEureka: false
        fetchRegistry: false
        serviceUrl:
          #defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/
          #defaultZone: http://admin:123@localhost:8761/eureka/
          defaultZone: http://${spring.security.user.name}:${spring.security.user.password}@master:8761/eureka/,http://${spring.security.user.name}:${spring.security.user.password}@slave02:8763/eureka/
          #注意:需要修改host文件配置
          #127.0.0.1 master
          #127.0.0.1 slave01
          #127.0.0.1 slave02

#### 2.3.3 eureka\_server02的配置文件 ####

server:
      port: 8763
    spring:
      application:
        name: eurka-server03
      security: #eureka的身份认证
        user:
          name: admin
          password: 123
    
    eureka:
      server:
        enable-self-preservation: true #开启自我保护机制
        renewal-percent-threshold: 0.85 #开启自我保护的阈值
        eviction-interval-timer-in-ms: 5000 #(代表是5秒,单位是毫秒,清理失效服务的间隔)
      instance:
        #instance-id: eureka-server03
        hostname: slave02
        preferIpAddress: true
        #调整自我保护机制的参数
        lease-renewal-interval-in-seconds: 30
        lease-expiration-duration-in-seconds: 90
      client:
        registerWithEureka: false
        fetchRegistry: false
        serviceUrl:
          #defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/
          #defaultZone: http://admin:123@localhost:8761/eureka/
          defaultZone: http://${spring.security.user.name}:${spring.security.user.password}@master:8761/eureka/,http://${spring.security.user.name}:${spring.security.user.password}@slave01:8762/eureka/
          #注意:需要修改host文件配置
          #127.0.0.1 master
          #127.0.0.1 slave01
          #127.0.0.1 slave02

#### 3. 配置host文件映射 ####

![Image 1][]![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3N5YzAwMDY2Ng_size_16_color_FFFFFF_t_70][]

#### 4. 创建一个eureka-client模块 ####

#### 4.1 client工程的application.yml文件 ####

server:
      port: 8764
    spring:
      application:
        name: service-client
      security: #eureka的身份认证
        user:
          name: admin
          password: 123
    eureka:
      instance:
        lease-renewal-interval-in-seconds: 30 #该配置指示eureka客户端需要向eureka服务器发送心跳的频率 (Spring Cloud默认该配置是 30s)
        lease-expiration-duration-in-seconds: 90 #该配置指示eureka服务器在接收到最后一个心跳之后等待的时间,如果服务端90秒还未收到心跳的话,就将该服务移除列表然后才能从列表中删除此实例 (Spring Cloud默认该配置是 90s)
      client:
        healthcheck:
          enabled: true #这个属性不会提示,修改健康检测方式为health监控
        serviceUrl:
          #defaultZone: http://localhost:8761/eureka/
          defaultZone: http://${spring.security.user.name}:${spring.security.user.password}@localhost:8761/eureka/
    #actuator设置
    management:
      endpoints:
        web:
          exposure:
            include: "*" #暴露所有端点,默认是info和health
      endpoint:
        health:
          show-details: always #默认是never

#### 5. 项目结构图 ####

![Image 1][]![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3N5YzAwMDY2Ng_size_16_color_FFFFFF_t_70 1][]

### 三. 启动项目 ###

#### 1. 分别启动3个eureka-server和1个eureka-client项目. ####

![Image 1][]![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3N5YzAwMDY2Ng_size_16_color_FFFFFF_t_70 2][]

#### 2. 分别进入到每个eureka-server的监控界面. ####

#### 2.1 8761-server ####

![Image 1][]![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3N5YzAwMDY2Ng_size_16_color_FFFFFF_t_70 3][]

#### 2.2 8762-server ####

![Image 1][]![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3N5YzAwMDY2Ng_size_16_color_FFFFFF_t_70 4][]

#### 2.3 8763-server ####

![Image 1][]![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3N5YzAwMDY2Ng_size_16_color_FFFFFF_t_70 5][]

#### 2.4 8764-client ####

![Image 1][]![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3N5YzAwMDY2Ng_size_16_color_FFFFFF_t_70 6][]

[Image 1]: 
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[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3N5YzAwMDY2Ng_size_16_color_FFFFFF_t_70 6]: https://image.dandelioncloud.cn/pgy_files/images/2024/01/29/73245a3b88644228991596c6b972030e.png