搭建高可用的Eureka注冊中心

搭建高可用的Eureka注冊中心

一、搭建高可用的Eureka的作用

　　當服務器因種種原因導致Eureka注冊中心(后面簡稱Eureka)服務當機(服務器跪了，異常關閉停止服務)。這樣就會影響到整個業務的流程，因為你把所有的業務都注冊到了Eureka中，當Eureka所依賴的docker(容器)當機了，這就會影響到所有在Eureka中注冊的服務全部error。因為Eureka的請求流程在上一篇中說過，當A服務向B服務發送一個請求的時候，他是不會直接請求B服務，首先A服務先會到Eureka，Eureka拿到A服務請求的api，Eureka會通過這個api會去找在Eureka中注冊的所有服務(這個過程叫做服務發現)，找到服務之后，Eureka會返回給A一個服務列表(因為B服務可能會做負載均衡，就是會向Eureka注冊兩個B服務，這個過程叫做服務消費)，當A服務拿到Eureka返回來的服務列表，根據自身的一些機制比如feign，ribbon等(這個后面都會講到)進行處理。

二、第一個Eureka搭建

1. pom.xml文件的配置

    1 <?xml version="1.0" encoding="UTF-8"?>
    2 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  3 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">  4 <modelVersion>4.0.0</modelVersion>  5  6 <groupId>cn.ds</groupId>  7 <artifactId>eureka-server-001</artifactId>  8 <version>0.0.1-SNAPSHOT</version>  9 <packaging>jar</packaging> 10 11 <name>eureka-server-001</name> 12 <description>Eureka服務-001</description> 13 14 <parent> 15 <groupId>org.springframework.boot</groupId> 16 <artifactId>spring-boot-starter-parent</artifactId> 17 <version>2.0.3.RELEASE</version> 18 <relativePath/> <!-- lookup parent from repository --> 19 </parent> 20 21 <properties> 22 <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> 23 <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> 24 <java.version>1.8</java.version> 25 <spring-cloud.version>Finchley.RELEASE</spring-cloud.version> 26 </properties> 27 28 <dependencies> 29 <dependency> 30 <groupId>org.springframework.boot</groupId> 31 <artifactId>spring-boot-starter-web</artifactId> 32 </dependency> 33 <!-- 引入Eureka服務 --> 34 <dependency> 35 <groupId>org.springframework.cloud</groupId> 36 <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId> 37 </dependency> 38 <dependency> 39 <groupId>org.springframework.boot</groupId> 40 <artifactId>spring-boot-devtools</artifactId> 41 <scope>runtime</scope> 42 </dependency> 43 <dependency> 44 <groupId>org.springframework.boot</groupId> 45 <artifactId>spring-boot-starter-test</artifactId> 46 <scope>test</scope> 47 </dependency> 48 </dependencies> 49 50 <dependencyManagement> 51 <dependencies> 52 <dependency> 53 <groupId>org.springframework.cloud</groupId> 54 <artifactId>spring-cloud-dependencies</artifactId> 55 <version>${spring-cloud.version}</version> 56 <type>pom</type> 57 <scope>import</scope> 58 </dependency> 59 </dependencies> 60 </dependencyManagement> 61 62 <build> 63 <plugins> 64 <plugin> 65 <groupId>org.springframework.boot</groupId> 66 <artifactId>spring-boot-maven-plugin</artifactId> 67 </plugin> 68 </plugins> 69 </build> 70 71 72 </project>

2. application.properties配置：這里需要注意的是，IP地址不能寫localhost或者127.0.0.1，后面會說到這個IP地址該怎么配置

    1 # Eureka注冊中心配置  2 # server-port：項目端口號  3 # spring-application-name：項目注冊到Eureka顯示的調用名稱，類似於域名  4 # eureka.client.register-with-erueka：是否將自己注冊到Eureka，默認為true  5 # eureka.client.fetch-registry：是否向Eureka獲取注冊信息，默認為true  6 # spring.jmx.default-domain：區分spring-boot項目  7 # eureka.instance.hostname：作為eureka-server-001服務配置中心  8 # eureka.client.service-url.defaultZone：雙節點注冊  9 server.port = 8080 10 spring.application.name = eureka-server 11 eureka.client.register-with-eureka = true 12 eureka.client.fetch-registry = true 13 spring.jmx.default-domain = erueka-server-001 14 eureka.instance.hostname = eureka-server-001 15 eureka.client.service-url.defaultZone = http://eureka-server-001:8080/eureka/,http://eureka-server-002:8081/eureka/

3. springboot啟動類配置

    1 package cn.yuzhenzi;  2  3 import org.springframework.boot.SpringApplication;  4 import org.springframework.boot.autoconfigure.SpringBootApplication;  5 import org.springframework.cloud.client.discovery.EnableDiscoveryClient;  6  7 /**  8  * @author 玉眞子  9  * @name springboot啟動類 10  * */ 11 @SpringBootApplication 12 @EnableEurekaServer //啟動注冊中心 13 public class Application { 14 15 public static void main(String[] args) { 16 SpringApplication.run(Application.class, args); 17  } 18 }　　

 

三、第二個Eureka搭建

1. pom.xml文件的配置

   <?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>
   
       <groupId>cn.ds</groupId>
       <artifactId>eureka-server-002</artifactId>
       <version>0.0.1-SNAPSHOT</version>
       <packaging>jar</packaging>
   
       <name>eureka-server-002</name>
       <description>Eureka服務-002</description>
   
       <parent>
           <groupId>org.springframework.boot</groupId>
           <artifactId>spring-boot-starter-parent</artifactId>
           <version>2.0.3.RELEASE</version>
           <relativePath/> <!-- lookup parent from repository -->
       </parent>
   
       <properties>
           <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
           <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
           <java.version>1.8</java.version>
           <spring-cloud.version>Finchley.RELEASE</spring-cloud.version>
       </properties>
   
       <dependencies>
           <dependency>
               <groupId>org.springframework.boot</groupId>
               <artifactId>spring-boot-starter-web</artifactId>
           </dependency>
           <!-- 引入Eureka服務 -->
           <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.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>
   
   
   </project>

2. application.properties文件的配置：這里需要注意的是，IP地址不能寫localhost或者127.0.0.1，后面會說到這個IP地址該怎么配置

   #    Eureka注冊中心配置
       #    server-port：項目端口號
       #    spring-application-name：項目注冊到Eureka顯示的調用名稱，類似於域名
       #    eureka.client.register-with-erueka：是否將自己注冊到Eureka，默認為true
       #    eureka.client.fetch-registry：是否向Eureka獲取注冊信息，默認為true
       #    spring.jmx.default-domain：區分spring-boot項目
       #    eureka.instance.hostname：作為eureka-server-001服務配置中心
       #    eureka.client.service-url.defaultZone：雙節點注冊
   server.port = 8081
   spring.application.name = eureka-server
   eureka.client.register-with-eureka = true
   eureka.client.fetch-registry = true
   spring.jmx.default-domain = eureka-server-002
   eureka.instance.hostname = eureka-server-002
   eureka.client.service-url.defaultZone = http://eureka-server-002:8081/eureka/,http://eureka-server-001:8080/eureka/

3. springboot啟動類的配置

   package cn.yuzhenzi;
   
   import org.springframework.boot.SpringApplication;
   import org.springframework.boot.autoconfigure.SpringBootApplication;
   import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
   
   /**
    * @author    玉眞子
    * @name    springboot啟動類
    * */
   @SpringBootApplication
   @EnableEurekaServer                //啟動注冊中心
   public class Application {
   
       public static void main(String[] args) {
           SpringApplication.run(Application.class, args);
       }
   }

四、IP配置以及注意事項

1. IP配置
   1. windows配置：/windows/system32/drivers/etc/hosts
      
   2. Linux配置：/etc/hosts
   3. 如圖所示：

       1 # Copyright (c) 1993-2009 Microsoft Corp.  2 #  3 # This is a sample HOSTS file used by Microsoft TCP/IP for Windows.  4 #  5 # This file contains the mappings of IP addresses to host names. Each  6 # entry should be kept on an individual line. The IP address should  7 # be placed in the first column followed by the corresponding host name.  8 # The IP address and the host name should be separated by at least one  9 # space. 10 # 11 # Additionally, comments (such as these) may be inserted on individual 12 # lines or following the machine name denoted by a '#' symbol. 13 # 14 # For example: 15 # 16 # 102.54.94.97 rhino.acme.com # source server 17 # 38.25.63.10 x.acme.com # x client host 18 19 # localhost name resolution is handled within DNS itself. 20 # 127.0.0.1 localhost 21 # ::1 localhost 22 127.0.0.1 eureka-server-001 23 127.0.0.1 eureka-server-002

2. 注意事項：當項目啟動時會報錯，這是正常現象，因為eureka-server-001要注冊到eureka-server-002上面，但是eureka-server-002項目還沒有啟動起來，所以會報錯

 

五、測試分別訪問http://localhost:8080/eureka/和http://localhost:8081/eureka/