搭建高可用的Eureka注册中心

搭建高可用的Eureka注册中心

一、搭建高可用的Eureka的作用

　　当服务器因种种原因导致Eureka注册中心(后面简称Eureka)服务当机(服务器跪了，异常关闭停止服务)。这样就会影响到整个业务的流程，因为你把所有的业务都注册到了Eureka中，当Eureka所依赖的docker(容器)当机了，这就会影响到所有在Eureka中注册的服务全部error。因为Eureka的请求流程在上一篇中说过，当A服务向B服务发送一个请求的时候，他是不会直接请求B服务，首先A服务先会到Eureka，Eureka拿到A服务请求的api，Eureka会通过这个api会去找在Eureka中注册的所有服务(这个过程叫做服务发现)，找到服务之后，Eureka会返回给A一个服务列表(因为B服务可能会做负载均衡，就是会向Eureka注册两个B服务，这个过程叫做服务消费)，当A服务拿到Eureka返回来的服务列表，根据自身的一些机制比如feign，ribbon等(这个后面都会讲到)进行处理。

二、第一个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服务-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服务 -->
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：这里需要注意的是，IP地址不能写localhost或者127.0.0.1，后面会说到这个IP地址该怎么配置 
     1 #    Eureka注册中心配置
 2     #    server-port：项目端口号
 3     #    spring-application-name：项目注册到Eureka显示的调用名称，类似于域名
 4     #    eureka.client.register-with-erueka：是否将自己注册到Eureka，默认为true
 5     #    eureka.client.fetch-registry：是否向Eureka获取注册信息，默认为true
 6     #    spring.jmx.default-domain：区分spring-boot项目
 7     #    eureka.instance.hostname：作为eureka-server-001服务配置中心
 8     #    eureka.client.service-url.defaultZone：双节点注册
 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启动类配置 
     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启动类
10  * */
11 @SpringBootApplication
12 @EnableEurekaServer            //启动注册中心
13 public class Application {
14 
15     public static void main(String[] args) {
16         SpringApplication.run(Application.class, args);
17     }
18 }　　

三、第二个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-002</artifactId>
 8     <version>0.0.1-SNAPSHOT</version>
 9     <packaging>jar</packaging>
10 
11     <name>eureka-server-002</name>
12     <description>Eureka服务-002</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服务 -->
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文件的配置：这里需要注意的是，IP地址不能写localhost或者127.0.0.1，后面会说到这个IP地址该怎么配置 
     1 #    Eureka注册中心配置
 2     #    server-port：项目端口号
 3     #    spring-application-name：项目注册到Eureka显示的调用名称，类似于域名
 4     #    eureka.client.register-with-erueka：是否将自己注册到Eureka，默认为true
 5     #    eureka.client.fetch-registry：是否向Eureka获取注册信息，默认为true
 6     #    spring.jmx.default-domain：区分spring-boot项目
 7     #    eureka.instance.hostname：作为eureka-server-001服务配置中心
 8     #    eureka.client.service-url.defaultZone：双节点注册
 9 server.port = 8081
10 spring.application.name = eureka-server
11 eureka.client.register-with-eureka = true
12 eureka.client.fetch-registry = true
13 spring.jmx.default-domain = eureka-server-002
14 eureka.instance.hostname = eureka-server-002
15 eureka.client.service-url.defaultZone = http://eureka-server-002:8081/eureka/,http://eureka-server-001:8080/eureka/
  3. springboot启动类的配置 
     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启动类
10  * */
11 @SpringBootApplication
12 @EnableEurekaServer                //启动注册中心
13 public class Application {
14 
15     public static void main(String[] args) {
16         SpringApplication.run(Application.class, args);
17     }
18 }

四、IP配置以及注意事项

  1. IP配置
    1. windows配置：/windows/system32/drivers/etc/hosts
    2. Linux配置：/etc/hosts
    3. 如图所示： 
       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. 注意事项：当项目启动时会报错，这是正常现象，因为eureka-server-001要注册到eureka-server-002上面，但是eureka-server-002项目还没有启动起来，所以会报错

五、测试分别访问http://localhost:8080/eureka/和http://localhost:8081/eureka/

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原文地址：https://www.cnblogs.com/yuzhenzi/p/9446611.html