Eureka【构建Multi Zone Eureka Server】

工程pom中公共依赖

<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>

1、Eureka Server工程

启动4个实例，配置两个zone，即zone1、zone2，每个zone都要2个eureka server实例，这个2个zone配置在同一个region上，即region-east。

1.1、eureka-server工程pom文件：

<!--加上文章头部的公共依赖-->

<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>

1.2、eureka-server工程启动类

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;

@SpringBootApplication
@EnableEurekaServer
public class EurekaServerApplication {

    public static void main(String[] args) {
        SpringApplication.run(EurekaServerApplication.class, args);
    }
}

1.3、eureka-server工程配置文件，路径：eureka-serversrcmain esources，分别有5个文件：application-zone1a.yml，application-zone1b.yml，application-zone2a.yml，application-zone2b.yml，application.yml

application-zone1a.yml：

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

application-zone1b.yml

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

application-zone2a.yml

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

application-zone2b.yml

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

application.yml

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

从上面的4个配置文件可以看出，我们通过eureka.instance.metadataMap.zone设置了每个实例所属的zone，接下来使用这4个配置启动4个eureka server实例：

//启动命令
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=zone2b

2、Eureka Client工程

这里配置2个eureka clent，分别属于zone1和zone2。

2.1、eureka-client工程pom文件

<!--加上文章头部公共配置-->

<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>

2.1、eureka-client工程启动类

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;

@SpringBootApplication
@EnableDiscoveryClient
public class EurekaClientApplication {

    public static void main(String[] args) {
        SpringApplication.run(EurekaClientApplication.class, args);
    }
}

2.2、eureka-client工程配置文件，路径：eureka-clientsrcmain esources，共3个文件：application.yml，application-zone1.yml，application-zone2.yml

application.yml：

#这里暴露所有的endpoints，便于后面验证
management:
  endpoints:
    web:
      exposure:
        include: '*'

application-zone1.yml：

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

application-zone2.yml：

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

2.3、启动eureka client，执行命令，启动2个实例：

mvn spring-boot:run -Dspring.profiles.active=zone1
mvn spring-boot:run -Dspring.profiles.active=zone2

3、Zuul Gateway工程

这里新建一个zuul网关工程，来演示metadataMap的zone属性中ZoneAffinity特性。

3.1、zuul gateway工程，pom文件：

<!--加上文章头部的公共依赖-->

<dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-zuul</artifactId>
        </dependency>
        <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>

3.2、zuul gateway工程启动类：

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.netflix.zuul.EnableZuulProxy;

@SpringBootApplication
@EnableDiscoveryClient
@EnableZuulProxy
public class ZuulGatewayApplication {

    public static void main(String[] args) {
        SpringApplication.run(ZuulGatewayApplication.class, args);
    }
}

3.3、zuul gateway工程配置文件，路径：zuul-gatewaysrcmain esources，一共3个文件：application.yml，application-zone1.yml，application-zone2.yml

application.yml：

spring:
  application:
    name: zuul-gateway
management:
  endpoints:
    web:
      exposure:
        include: '*'

application-zone1.yml：

server:
  port: 10001
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

application-zone2.yml：

server:
  port: 10002
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

3.4、启动zuul gateway工程，一共2个实例，执行命令：

mvn spring-boot:run -Dspring.profiles.active=zone1
mvn spring-boot:run -Dspring.profiles.active=zone2

验证ZoneAffinity，访问：localhost:10001/client/actuator/env，结果：

 访问：localhost:10002/client/actuator/env，结果：

 可以看出请求网关/client/actuator/env，访问的是eureka client实例的/actuator/env接口，处于zone1的Gateway返回的activeProfiles为zone1，处于zone2的Gateway返回的activeProfiles是zone2。