Spring Cloud Eureka动态扩容

以你之姓@ 2022-05-13 14:16 377阅读 0赞

## 前言 ##

本文心得包括案例基于《重新定义》，动态扩容Eureka是为了不影响已运行服务的情况下进行扩容。

## 正文 ##

利用了config进行统一管理了eureka服务的配置，**首先创建一个父module**，主要就是把web工程依赖的jar包含在内，pom如下

<groupId>cn.springcloud.book</groupId>
    	<artifactId>ch3-1</artifactId>
    	<version>0.0.1-SNAPSHOT</version>
    	<packaging>pom</packaging>
    
    	<name>ch3-1</name>
    	<description>ch3-1</description>
    
    	<modules>
    		<module>ch3-1-config-server</module>
    		<module>ch3-1-eureka-server</module>
    		<module>ch3-1-eureka-client</module>
    	</modules>
    
    	<parent>
    		<groupId>org.springframework.boot</groupId>
    		<artifactId>spring-boot-starter-parent</artifactId>
    		<version>2.0.3.RELEASE</version>
    		<relativePath/> 
    	</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>
    
    	<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>
    
    	<dependencies>
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-actuator</artifactId>
    		</dependency>
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-web</artifactId>
    		</dependency>
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-test</artifactId>
    			<scope>test</scope>
    		</dependency>
    	</dependencies>

**然后在这个父module下创建ConfigServer 名为：ch3-1-config-server，pom如下**

<parent>
            <groupId>cn.springcloud.book</groupId>
            <artifactId>ch3-1</artifactId>
            <version>0.0.1-SNAPSHOT</version>
            <relativePath>../pom.xml</relativePath> 
        </parent>
    
        <properties>
            <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
            <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
            <java.version>1.8</java.version>
        </properties>
    
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-config-server</artifactId>
            </dependency>
        </dependencies>

当前configserver的main方法及配置文件

@SpringBootApplication
    @EnableConfigServer
    public class Ch31ConfigServerApplication {
    
        public static void main(String[] args) {
            SpringApplication.run(Ch31ConfigServerApplication.class, args);
        }
    }

spring:
      application:
        name: config-server
      profiles:
        active: native
    server:
      port: 8888

在resources下创建一个目录叫 config，里面创建三个yml文件，这里为了方便，我建了三个配置文件。代码如下

第一个是eureka的客户端配置文件

server:
      port: 8081
    
    spring:
      application:
        name: eureka-client1
    
    eureka:
      client:
        serviceUrl:
    #      defaultZone: http://localhost:8761/eureka/ # one eureka server
    #      defaultZone: http://localhost:8761/eureka/,http://localhost:8762/eureka/ # two eureka server
          defaultZone: http://localhost:8761/eureka/,http://localhost:8762/eureka/,http://localhost:8763/eureka/ # three eureka server

第二个是eureka服务的peer1文件

server:
      port: 8761
    
    spring:
      application:
        name: eureka-server
    eureka:
      instance:
        hostname: localhost
        preferIpAddress: true
      client:
        registerWithEureka: true
        fetchRegistry: true
        serviceUrl:
    #      defaultZone: http://localhost:8761/eureka/ # one eureka server
    #      defaultZone: http://localhost:8762/eureka/ # two eureka server
          defaultZone: http://localhost:8762/eureka/,http://localhost:8763/eureka/ # three eureka server
      server:
          waitTimeInMsWhenSyncEmpty: 0
          enableSelfPreservation: false

第三个是eureka服务的peer2文件

server:
      port: 8762
    
    eureka:
      instance:
        hostname: localhost
        preferIpAddress: true
      client:
        registerWithEureka: true
        fetchRegistry: true
        serviceUrl:
    #      defaultZone: http://localhost:8761/eureka/ # two eureka server
          defaultZone: http://localhost:8761/eureka/,http://localhost:8763/eureka/ # three eureka server
      server:
          waitTimeInMsWhenSyncEmpty: 0
          enableSelfPreservation: false

**创建EurekaServer 工程名：ch3-1-eureka-server**

pom文件

<groupId>cn.springcloud.book</groupId>
        <artifactId>ch3-1-eureka-server</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <packaging>jar</packaging>
    
        <name>ch3-1-eureka-server</name>
        <description>ch3-1-eureka-server</description>
    
        <parent>
            <groupId>cn.springcloud.book</groupId>
            <artifactId>ch3-1</artifactId>
            <version>0.0.1-SNAPSHOT</version>
            <relativePath>../pom.xml</relativePath> 
        </parent>
    
        <properties>
            <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
            <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
            <java.version>1.8</java.version>
        </properties>
    
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-config</artifactId>
            </dependency>
        </dependencies>

eureka服务的两个配置文件如下，分别是bootstrap.yml 和application.yml

spring:
      application:
        name: eureka-server
      cloud:
        config:
          uri: http://localhost:8888
    management:
      endpoints:
        web:
          exposure:
            include: '*'

eureka:
      server:
        peer-eureka-nodes-update-interval-ms: 10000 #默认是10分钟即600000，这里为了验证改为10秒

main方法启动类

@SpringBootApplication
    @EnableEurekaServer
    public class Ch31EurekaServerApplication {
    
        public static void main(String[] args) {
            SpringApplication.run(Ch31EurekaServerApplication.class, args);
        }
    }

**最后一个就是创建eurakaClient**

他的配置文件和eureka服务的两个配置文件都一样分别是bootstrap.yml 和application.yml ，区别是

spring:
      application:
        name: eureka-client

eurekaClient 的启动类

@SpringBootApplication
    @EnableDiscoveryClient
    public class Ch31EurekaClientApplication {
    
        public static void main(String[] args) {
            SpringApplication.run(Ch31EurekaClientApplication.class, args);
        }
    }

现在所有代码都准备好了，我们来首先启动configServer

然后，下面的操作很关键，大家一定跟上，我会说的很清楚的

![70][]

启动时会有报错信息，不要管，最后的结果是启动成功就ok

![70 1][]

访问 [http://localhost:8761/][http_localhost_8761]，可以看到注册成功

![70 2][]

**下面就开始进行对eureka-server进行动态扩容了**

我们来修改peer1文件

![70 3][]

然后修改peer2文件

![70 4][]

![70 5][]

然后我们重启config-server，使配置生效。然后用如下命令分别刷新eureka-client以及eureka-server-peer1

![70 6][]

分别访问[http://localhost:8761/][http_localhost_8761] ，和[http://localhost:8762/][http_localhost_8762]，这里只截一个图了。

![70 7][]

### 动态扩容成功 ###

注：对本文有异议或不明白的地方微信探讨，wx：15524579896

[70]: /images/20220504/710105785a48479db49dfde46f527ab7.png
[70 1]: /images/20220504/37c915a6ddd44280829de47b291483e4.png
[http_localhost_8761]: http://localhost:8761/
[70 2]: /images/20220504/eb7b6f8940fb4120af4f9c09cd405bc6.png
[70 3]: /images/20220504/f196983a923d46979ec7d1df4f359ddd.png
[70 4]: /images/20220504/a4967823c3584479b81649227cc5654a.png
[70 5]: /images/20220504/7c82334f36924e28ac92dc776cd76245.png
[70 6]: /images/20220504/c2ff82e38c184e7cb827467aa62476d7.png
[http_localhost_8762]: http://localhost:8762/
[70 7]: /images/20220504/cbd1aafb7210492b92da1790575c2415.png