SpringCloud的Region和Zone的区别
1、Region和Zone是一对多的关系。
2、服务注册和发现都会按先指定的Region，然后根据指定的Region寻找第一个Zone。
3、Zone相当于组成Region的基本单元。
样例：
分区服务的部署架构图
介绍：如上图所示，一个region:beijing，下面有zone-1和zone-2两个分区，每个分区内有一个注册中心Eureka Server和一个服务提供者Service。我们在zone-1内创建一个
Consumer-1服务消费者的话，其会优先调用同一个zone内的Service-1，当Service-1不可用时，才会去调用zone-2内的Service-2。
配置文件：
（1）Eureka Server-1：
spring:
application:
name: Server-1
server:
port: 30000
eureka:
instance:
prefer-ip-address: true
status-page-url-path: /actuator/info
health-check-url-path: /actuator/health
hostname: localhost
client:
register-with-eureka: true
fetch-registry: true
prefer-same-zone-eureka: true
#地区
region: beijing
availability-zones:
beijing: zone-1,zone-2
service-url:
zone-1: http://localhost:30000/eureka/
zone-2: http://localhost:30001/eureka/
（2）Eureka Server-2：
spring:
application:
name: Server-2
server:
port: 30001
eureka:
instance:
prefer-ip-address: true
status-page-url-path: /actuator/info
health-check-url-path: /actuator/health
hostname: localhost
client:
register-with-eureka: true
fetch-registry: true
prefer-same-zone-eureka: true
#地区
region: beijing
availability-zones:
beijing: zone-2,zone-1
service-url:
zone-1: http://localhost:30000/eureka/
zone-2: http://localhost:30001/eureka/
（3）Service1
测试代码
@RestController
public class HiController {
@Value("${zone.name}")
private String zoneName;
@RequestMapping(value = "/hi", method = RequestMethod.GET)
public String hi() {
return zoneName;
}
}
}
配置文件
spring:
application:
name: service
server:
port: 30010
eureka:
instance:
prefer-ip-address: true
status-page-url-path: /actuator/info
health-check-url-path: /actuator/health
metadata-map:
zone: zone-1
client:
register-with-eureka: true
fetch-registry: true
prefer-same-zone-eureka: true
#地区
region: beijing
availability-zones:
beijing: zone-1,zone-2
service-url:
zone-1: http://localhost:30000/eureka/
zone-2: http://localhost:30001/eureka/
zone.name: zone-1
（4）Service2
spring:
application:
name: service
server:
port: 30011
eureka:
instance:
prefer-ip-address: true
status-page-url-path: /actuator/info
health-check-url-path: /actuator/health
metadata-map:
zone: zone-2
client:
register-with-eureka: true
fetch-registry: true
prefer-same-zone-eureka: true
#地区
region: beijing
availability-zones:
beijing: zone-2,zone-1
service-url:
zone-1: http://localhost:30000/eureka/
zone-2: http://localhost:30001/eureka/
zone.name: zone-2
（5）Consumer-1
测试代码
@RestController
public class HiController {
@Autowired
private RestTemplate restTemplate;
@RequestMapping(value="/consumer")
public String hi() {
return restTemplate.getForObject("http://service/hi", String.class);
}
}
}
配置文件
spring:
application:
name: consumer
server:
port: 30030
eureka:
instance:
prefer-ip-address: true
status-page-url-path: /actuator/info
health-check-url-path: /actuator/health
metadata-map:
zone: zone-1
client:
register-with-eureka: true
fetch-registry: true
prefer-same-zone-eureka: true
#地区
region: beijing
availability-zones:
beijing: zone-1,zone-2
service-url:
zone-1: http://localhost:30000/eureka/
zone-2: http://localhost:30001/eureka/
总结
1、如果eureka.client.prefer-same-zone-eureka为false，则不按照优先加载同一个zone下的服务，按照eureka.client.service-url下的数据结构为map的第一个EntrySet声明的注册中心来注册。如果为true，会先通过指定的Region取availablility-zones的第一个Zone1，然后在service-url下的Zone1取第一个注册中心地址注册。只在第一个注册失败的情况下，才会依次向其它的注册中心注册，总共重试3次，如果3个service-url都没有注册成
功，则注册失败。每隔一个心跳时间，会再次尝试。
2、通过eureka.client.region指定服务消费者和服务供着属于哪个Region
3、服务消费者和服务提供者分别属于哪个Zone，均是通过eureka.instance.metadata-map.zone来判定的