工程公共pom依赖
UTF-8
UTF-8
1.8
Finchley.RELEASE
org.springframework.cloud
spring-cloud-dependencies
${spring-cloud.version}
pom
import
1、eureka server工程
1.1、eureka server工程pom依赖：
org.springframework.cloud
spring-cloud-starter-netflix-eureka-server
org.springframework.boot
spring-boot-maven-plugin
1.2、项目启动类：
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;
@SpringBootApplication
@EnableEurekaServer
public class EurkeaServerApplication {
public static void main(String[] args) {
SpringApplication.run(EurkeaServerApplication.class, args);
}
}
1.3、这里配置4个eureka server实例，路径：eureka-server\src\main\resources\，分4个zone，属于region-east、region-west两个区。
属于region-east的配置文件为：application-zone1.yml，application-zone2.yml
application-zone1.yml：
server:
port: 8761
spring:
application:
name: eureka-server
eureka:
server:
waitTimeInMsWhenSyncEmpty: 0
enableSelfPreservation: false
remoteRegionUrlsWithName:
region-west: http://localhost:8763/eureka/
client:
register-with-eureka: true
fetch-registry: true
region: region-east
service-url:
zone1: http://localhost:8761/eureka/
zone2: http://localhost:8762/eureka/
availability-zones:
region-east: zone1,zone2
instance:
hostname: localhost
metadataMap.zone: zone1
application-zone2.yml：
server:
port: 8762
spring:
application:
name: eureka-server
eureka:
server:
waitTimeInMsWhenSyncEmpty: 0
enableSelfPreservation: false
remoteRegionUrlsWithName:
region-west: http://localhost:8763/eureka/
client:
register-with-eureka: true
fetch-registry: true
region: region-east
service-url:
zone1: http://localhost:8761/eureka/
zone2: http://localhost:8762/eureka/
availability-zones:
region-east: zone1,zone2
instance:
hostname: localhost
metadataMap.zone: zone2
属于region-west的配置文件为：application-zone3-region-west.yml，application-zone4-region-west.yml
application-zone3-region-west.yml
server:
port: 8763
spring:
application:
name: eureka-server
eureka:
server:
waitTimeInMsWhenSyncEmpty: 0
enableSelfPreservation: false
remoteRegionUrlsWithName:
region-east: http://localhost:8761/eureka/
client:
register-with-eureka: true
fetch-registry: true
region: region-west
service-url:
zone3: http://localhost:8763/eureka/
zone4: http://localhost:8764/eureka/
availability-zones:
region-west: zone3,zone4
instance:
hostname: localhost
metadataMap.zone: zone3
application-zone4-region-west.yml
server:
port: 8764
spring:
application:
name: eureka-server
eureka:
server:
waitTimeInMsWhenSyncEmpty: 0
enableSelfPreservation: false
remoteRegionUrlsWithName:
region-east: http://localhost:8761/eureka/
client:
register-with-eureka: true
fetch-registry: true
region: region-west
service-url:
zone3: http://localhost:8763/eureka/
zone4: http://localhost:8764/eureka/
availability-zones:
region-west: zone3,zone4
instance:
hostname: localhost
metadataMap.zone: zone4
由于框架中，EurekaServerConfigBean的remoteRegionAppWhitelist默认值是null，而getRemoteRegionAppWhitelist(String regionName)方法又被直接调用，如果工程上不处理，就直接空指针异常了。
//框架源码
package org.springframework.cloud.netflix.eureka.server;
import ......
@ConfigurationProperties("eureka.server")
public class EurekaServerConfigBean implements EurekaServerConfig {
public static final String PREFIX = "eureka.server";
private static final int MINUTES = 60000;
@Autowired(
required = false
)
PropertyResolver propertyResolver;
private String aWSAccessId;
//.....private String[] remoteRegionUrls;
private Map> remoteRegionAppWhitelist;
//......
}
so，在eureka server工程中加入以下配置：
import com.netflix.discovery.EurekaClientConfig;
import com.netflix.eureka.EurekaServerConfig;
import org.springframework.boot.autoconfigure.AutoConfigureBefore;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.cloud.netflix.eureka.server.EurekaServerAutoConfiguration;
import org.springframework.cloud.netflix.eureka.server.EurekaServerConfigBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import java.util.HashMap;
/**
* 配置类
*/
@Configuration
@AutoConfigureBefore(EurekaServerAutoConfiguration.class)//当前配置类EurekaServerAutoConfiguration加载完毕后的后续加载操作
public class RegionConfig {
@Bean
@ConditionalOnMissingBean
public EurekaServerConfig eurekaServerConfig(EurekaClientConfig clientConfig) {
EurekaServerConfigBean server = new EurekaServerConfigBean();
if (clientConfig.shouldRegisterWithEureka()) {
server.setRegistrySyncRetries(5);
}
server.setRemoteRegionAppWhitelist(new HashMap<>());
return server;
}
}
1.4、启动实例，执行命令：
mvn spring-boot:run -Dspring.profiles.active=zone1
mvn spring-boot:run -Dspring.profiles.active=zone2
mvn spring-boot:run -Dspring.profiles.active=zone3-region-west
mvn spring-boot:run -Dspring.profiles.active=zone4-region-west
2、Eureka Client工程
2.1、eureka client工程pom依赖：
org.springframework.cloud
spring-cloud-starter-netflix-eureka-client
org.springframework.boot
spring-boot-maven-plugin
2.2、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);
}
}
2.3、eureka client工程配置文件
这里配置4个client实例，也是分4个zone，属于region-east、region-west两个区。
属于region-east的配置文件为：application-zone1.yml，application-zone2.yml
application-zone1.yml：
server:
port: 8071
spring:
application.name: demo-client
eureka:
client:
prefer-same-zone-eureka: true
region: region-east
service-url:
zone1: http://localhost:8761/eureka/
zone2: http://localhost:8762/eureka/
availability-zones:
region-east: zone1,zone2
instance:
metadataMap.zone: zone1
application-zone2.yml
server:
port: 8072
spring:
application.name: demo-client
eureka:
client:
prefer-same-zone-eureka: true
region: region-east
service-url:
zone1: http://localhost:8761/eureka/
zone2: http://localhost:8762/eureka/
availability-zones:
region-east: zone1,zone2
instance:
metadataMap.zone: zone2
属于region-west的配置文件为：application-zone3.yml，application-zone4.yml
application-zone3.yml：
server:
port: 8073
spring:
application.name: demo-client
eureka:
client:
prefer-same-zone-eureka: true
region: region-west
service-url:
zone3: http://localhost:8763/eureka/
zone4: http://localhost:8764/eureka/
availability-zones:
region-west: zone3,zone4
instance:
metadataMap.zone: zone3
application-zone4.yml：
server:
port: 8074
spring:
application.name: demo-client
eureka:
client:
prefer-same-zone-eureka: true
region: region-west
service-url:
zone3: http://localhost:8763/eureka/
zone4: http://localhost:8764/eureka/
availability-zones:
region-west: zone3,zone4
instance:
metadataMap.zone: zone4
application.yml：
management:
endpoints:
web:
exposure:
include: ‘*‘
2.4、启动eureka client工程，执行命令：
mvn spring-boot:run -Dspring.profiles.active=zone1
mvn spring-boot:run -Dspring.profiles.active=zone2
mvn spring-boot:run -Dspring.profiles.active=zone3
mvn spring-boot:run -Dspring.profiles.active=zone4
3、Zuul Gateway工程
3.1、zuul gateway工程pom依赖：
org.springframework.cloud
spring-cloud-starter-netflix-zuul
org.springframework.cloud
spring-cloud-starter-netflix-eureka-client
org.springframework.boot
spring-boot-maven-plugin
3.2、zuul gateway工程启动类：
package cn.springcloud.book;
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
@EnableZuulProxy
@EnableDiscoveryClient
public class ZuulGatewayApplication {
public static void main(String[] args) {
SpringApplication.run(ZuulGatewayApplication.class, args);
}
}
3.3、zuul gateway工程配置文件，这里使用2个gateway实例来演示fallback到remote region的应用实例功能，配置文件一个属于region-east，一个属于region-west。
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/
zone2: http://localhost:8762/eureka/
availability-zones:
region-east: zone1,zone2
application-zone3-region-west.yml：
server:
port: 10002
eureka:
instance:
metadataMap.zone: zone3
client:
register-with-eureka: true
fetch-registry: true
region: region-west
service-url:
zone3: http://localhost:8763/eureka/
zone4: http://localhost:8764/eureka/
availability-zones:
region-west: zone3,zone4
3.4、启动gateway工程，执行命令：
mvn spring-boot:run -Dspring.profiles.active=zone1
mvn spring-boot:run -Dspring.profiles.active=zone3-region-west
访问：localhost:10001/demo-client/actuator/env，结果如下：
访问：localhost:10002/demo-client/actuator/env，结果如下：
可以看到ZoneAffinity特性（上一篇文章有讲），zone1的gateway访问的是zone1的demo-client，zone3的gateway访问的是zone3的demo-client。
接下来，关闭eureka-client的zone1实例，继续访问 localhost:10001/demo-client/actuator/env，可以看到在经过几个错误之后，自动fallback到了remote-region的zone4实例上，实现了类似异地多活自动转移请求的效果。
Eureka实战-3【支持Remote Region】
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