多节点高可用Eureka集群配置与部署

港控/mmm° 2022-05-13 15:24 518阅读 0赞

## 前言 ##

上一节讲的是动态扩容Eureka服务，说实话，一般情况这种操作并不多，一般多用在，由于大量服务节点部署后给Eureka造成压力突然积增，而解决的办法。这节讲的是一次启动或部署，直接就是集群多节点的，多用于服务节点相对稳定的场景。还有笔者这里有实际部署和应用的经验分享给大家，就是，我目前25个服务都注册在一个单节点Eureka上了（无论生产还是测试环境下），测试周期接近一年，我发现Eureka可靠性和可用性还是很高的，没有出现一次注册中心挂了的情况。还有，我一下内容没有花里胡哨的套话和流程图，想必大家最想解决的就是如何快速的解决自己的问题，所以以下基本都是贴出的代码，关键地方我会文字说明。代码还是基于《重新定义》的思想。

## 正文 ##

**首先还是创建一个父module**，pom配置如下：

<groupId>cn.springcloud.book</groupId>
    	<artifactId>ch3-2</artifactId>
    	<version>0.0.1-SNAPSHOT</version>
    	<packaging>pom</packaging>
    
    	<name>ch3-2</name>
    	<description>ch3-2</description>
    
    	<modules>
    		<module>ch3-2-zuul-gateway</module>
    		<module>ch3-2-eureka-server</module>
    		<module>ch3-2-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>

**然后创建EurekaServer服务**，分别贴出pom文件和启动类

<groupId>cn.springcloud.book</groupId>
        <artifactId>ch3-2-eureka-server</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <packaging>jar</packaging>
    
        <name>ch3-2-eureka-server</name>
        <description>ch3-2-eureka-server</description>
    
        <parent>
            <groupId>cn.springcloud.book</groupId>
            <artifactId>ch3-2</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>
        </dependencies>
    
        <build>
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                </plugin>
            </plugins>
        </build>

@SpringBootApplication
    @EnableEurekaServer
    public class Ch322EurekaServerApplication {
    
        public static void main(String[] args) {
            SpringApplication.run(Ch322EurekaServerApplication.class, args);
        }
    }

###  然后下面的内容是多节点配置的重要部分了 ###

我会从上到下依次贴出这个目录的代码

![70][]

eureka:
      server:
        use-read-only-response-cache: false
        response-cache-auto-expiration-in-seconds: 10
    management:
      endpoints:
        web:
          exposure:
            include: '*'

server:
      port: 8761
    spring:
      application:
        name: eureka-server
    eureka:
      instance:
        hostname: localhost
        preferIpAddress: true
        metadataMap.zone: zone1
      client:
        register-with-eureka: true
        fetch-registry: true
        region: region-east
        service-url:
          zone1: http://localhost:8761/eureka/,http://localhost:8762/eureka/
          zone2: http://localhost:8763/eureka/,http://localhost:8764/eureka/
        availability-zones:
          region-east: zone1,zone2
      server:
          waitTimeInMsWhenSyncEmpty: 0
          enableSelfPreservation: false

server:
      port: 8762
    spring:
      application:
        name: eureka-server
    eureka:
      instance:
        hostname: localhost
        preferIpAddress: true
        metadataMap.zone: zone1
      client:
        register-with-eureka: true
        fetch-registry: true
        region: region-east
        service-url:
          zone1: http://localhost:8761/eureka/,http://localhost:8762/eureka/
          zone2: http://localhost:8763/eureka/,http://localhost:8764/eureka/
        availability-zones:
          region-east: zone1,zone2
      server:
          waitTimeInMsWhenSyncEmpty: 0
          enableSelfPreservation: false

server:
      port: 8763
    spring:
      application:
        name: eureka-server
    eureka:
      instance:
        hostname: localhost
        preferIpAddress: true
        metadataMap.zone: zone2
      client:
        register-with-eureka: true
        fetch-registry: true
        region: region-east
        service-url:
          zone1: http://localhost:8761/eureka/,http://localhost:8762/eureka/
          zone2: http://localhost:8763/eureka/,http://localhost:8764/eureka/
        availability-zones:
          region-east: zone1,zone2
      server:
          waitTimeInMsWhenSyncEmpty: 0
          enableSelfPreservation: false

server:
      port: 8764
    spring:
      application:
        name: eureka-server
    eureka:
      instance:
        hostname: localhost
        preferIpAddress: true
        metadataMap.zone: zone2
      client:
        register-with-eureka: true
        fetch-registry: true
        region: region-east
        service-url:
          zone1: http://localhost:8761/eureka/,http://localhost:8762/eureka/
          zone2: http://localhost:8763/eureka/,http://localhost:8764/eureka/
        availability-zones:
          region-east: zone1,zone2
      server:
          waitTimeInMsWhenSyncEmpty: 0
          enableSelfPreservation: false

###  这里值得解释的是 ###

上面我配置的是四个节点，分别在一个区域里，用region: region-east 配置，然后这个区域有两个空间分别是zone1和zone2

availability-zones:
      region-east: zone1,zone2
     这个配置代表了

然后8761和8762在zone1空间里，8763和8764在zone2空间里，请大家仔细看我上面的配置，按照配置理解用意。

还有必要解释的是WaitTimeInMsWhenSyncEmpty(\*)：

这个设置为0是为了尽快让eureka server启动起来就提供rest api服务。默认是5分钟，也就是如果peer节点注册列表为空，那就等5分钟让其他服务有注册上来了，然后同步过来，再对外提供rest api服务。

UseReadOnlyResponseCache（\*）：

目前采用的是二级缓存策略，一个是读写高速缓存过期策略，另一个没有过期只有只读缓存，默认为true，表示只读缓存。

然后进入eureka-server目录下分别执行

mvn spring-boot:run -Dspring.profiles.active=zone1a

mvn spring-boot:run -Dspring.profiles.active=zone1b

mvn spring-boot:run -Dspring.profiles.active=zone2a

mvn spring-boot:run -Dspring.profiles.active=zone1b

切记每次执行下一条命令需要再打开一个Terminal

![70 1][]

![70 2][]

这里笔者全部启动成功了。其实这时候你们访问[http://localhost:8761/][http_localhost_8761] 任意节点都是可以看到的。

**但是我为了更好说明问题，这里加入一个eureka-client，并且这个客户端是双节点的，分别在zone1和zone2各一个**

下面是client的pom和启动类

<groupId>cn.springcloud.book</groupId>
        <artifactId>ch3-2-eureka-client</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <packaging>jar</packaging>
    
        <name>ch3-2-eureka-client</name>
        <description>ch3-2-eureka-client</description>
    
        <parent>
            <groupId>cn.springcloud.book</groupId>
            <artifactId>ch3-2</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-client</artifactId>
            </dependency>
        </dependencies>
    
        <build>
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                </plugin>
            </plugins>
        </build>

@SpringBootApplication
    @EnableDiscoveryClient
    public class Ch32EurekaClientApplication {
    
    	public static void main(String[] args) {
    		SpringApplication.run(Ch32EurekaClientApplication.class, args);
    	}
    }

下面我同样分别列出client的配置文件

![70 3][]

management:
      endpoints:
        web:
          exposure:
            include: '*'

server:
      port: 8081
    spring:
      application:
        name: client
    eureka:
      instance:
        metadataMap.zone: zone1
      client:
        register-with-eureka: true
        fetch-registry: true
        region: region-east
        service-url:
          zone1: http://localhost:8761/eureka/,http://localhost:8762/eureka/
          zone2: http://localhost:8763/eureka/,http://localhost:8764/eureka/
        availability-zones:
          region-east: zone1,zone2

server:
      port: 8082
    spring:
      application:
        name: client
    eureka:
      instance:
        metadataMap.zone: zone2
      client:
        register-with-eureka: true
        fetch-registry: true
        region: region-east
        service-url:
          zone1: http://localhost:8761/eureka/,http://localhost:8762/eureka/
          zone2: http://localhost:8763/eureka/,http://localhost:8764/eureka/
        availability-zones:
          region-east: zone1,zone2

下面分别用命令启动两个节点，操作也是和eurekaServer是一样的，进入到client目录

分别使用mvn spring-boot:run -Dspring.profiles.active=zone1 和mvn spring-boot:run -Dspring.profiles.active=zone2

![70 4][]

访问[http://localhost:8761/][http_localhost_8761]

![70 5][]

大家可以四个节点都访问以下，展示的页面和这一个是一样的。

好了，到这里已经讲解完多节点配置和应用了，

下面如果把这两个工程打成jar在服务器上分别启动不同配置文件jar的时候

用java -Dspring.profiles.active=prod -jar xxx.jar 命令

注：大家可能看到我的副本均是不可用的，原因是我四个节点都是在本地，需要改hosts文件，

由于我在当前Demo没有做这些，所以后期我在本地补了一部分，这回所有节点都是可用的，如下图需要改几个地方。

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zODAwMzM4OQ_size_16_color_FFFFFF_t_70][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zODAwMzM4OQ_size_16_color_FFFFFF_t_70 1][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zODAwMzM4OQ_size_16_color_FFFFFF_t_70 2][]

对本文有异议或不明白的地方微信探讨，wx：15524579896

[70]: /images/20220504/a778287c4f7a4f6c9b9598d6a3eebf9d.png
[70 1]: /images/20220504/f3d786362e92492da1d3696e2249126a.png
[70 2]: /images/20220504/a5149808a0c44b5a98c3b88511c3da72.png
[http_localhost_8761]: http://localhost:8761/
[70 3]: /images/20220504/bcbbfaa3e5144800a25ca2bb5f30a23f.png
[70 4]: /images/20220504/a71b2052387a447786293a0a86075f50.png
[70 5]: /images/20220504/74e1ce11b4f14ca8ab2816604a6065b3.png
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[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zODAwMzM4OQ_size_16_color_FFFFFF_t_70 1]: /images/20220504/ea8fd79fcc8a4ef185017ccb6eb868d3.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zODAwMzM4OQ_size_16_color_FFFFFF_t_70 2]: /images/20220504/aa3d585b5e684a71a8f2f64d2455b605.png