微服务客户端负载均衡组件Ribbon-阿里云开发者社区

负载均衡分类

服务端负载均衡

常见的服务端负载均衡有Nginx，客户端将请求发送给Nginx，Nginx根据负载均衡算法选择一个服务器调用，具体调用哪个服务器由Nginx说了算，客户端是不知道服务器的真实IP的。

客户端负载均衡

Spring Cloud Ribbon是基于NetFilix Ribbon实现的一套客户端负载均衡，Ribbon客户端组件提供了一系列的完善的配置，例如超时，重试等。客户端从注册中心获取到服务器的列表，由客户端自己根据负载均衡算法选择将流量分发给哪个服务器，客户端是知道服务器的真实IP的。

重写RestTemplate的doExecute()方法实现负载均衡

通过阅读RestTemplate源码得知，不管是POST,GET请求，最终都会调用doExecute()方法,因此我们可以通过继承RestTemplate类并重写doExecute()方法来实现负载均衡算法。

package com.tuling.config;
import lombok.extern.slf4j.Slf4j;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.discovery.DiscoveryClient;
import org.springframework.http.HttpMethod;
import org.springframework.http.client.ClientHttpRequest;
import org.springframework.http.client.ClientHttpResponse;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.web.client.*;
import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.List;
import java.util.Random;
/**
 * 根据RestTemplate特性自己改造
 */
@Slf4j
public class TulingRestTemplate extends RestTemplate {
    private DiscoveryClient discoveryClient;
    public TulingRestTemplate (DiscoveryClient discoveryClient) {
        this.discoveryClient = discoveryClient;
    }
    protected <T> T doExecute(URI url, @Nullable HttpMethod method, @Nullable RequestCallback requestCallback,
                              @Nullable ResponseExtractor<T> responseExtractor) throws RestClientException {
        Assert.notNull(url, "URI is required");
        Assert.notNull(method, "HttpMethod is required");
        ClientHttpResponse response = null;
        try {
            log.info("请求的url路径为:{}",url);
            //把服务名 替换成我们的IP
            url = replaceUrl(url);
            log.info("替换后的路径:{}",url);
            ClientHttpRequest request = createRequest(url, method);
            if (requestCallback != null) {
                requestCallback.doWithRequest(request);
            }
            response = request.execute();
            handleResponse(url, method, response);
            return (responseExtractor != null ? responseExtractor.extractData(response) : null);
        }
        catch (IOException ex) {
            String resource = url.toString();
            String query = url.getRawQuery();
            resource = (query != null ? resource.substring(0, resource.indexOf('?')) : resource);
            throw new ResourceAccessException("I/O error on " + method.name() +
                    " request for \"" + resource + "\": " + ex.getMessage(), ex);
        } finally {
            if (response != null) {
                response.close();
            }
        }
    }
    /**
     * 方法实现说明:把微服务名称去注册中心拉取对应IP进行替换
     * http://product-center/selectProductInfoById/1
     * @param url:请求的url
     * @return: 替换后的url
     * @exception:
     * @date:2020/2/6 13:11
     */
    private URI replaceUrl(URI url){
        //1:从URI中解析调用的调用的serviceName=product-center
        String serviceName = url.getHost();
        log.info("调用微服务的名称:{}",serviceName);
        //2:解析我们的请求路径 reqPath= /selectProductInfoById/1
        String reqPath = url.getPath();
        log.info("请求path:{}",reqPath);
        //通过微服务的名称去nacos服务端获取 对应的实例列表
        List<ServiceInstance> serviceInstanceList = discoveryClient.getInstances(serviceName);
        if(serviceInstanceList.isEmpty()) {
            throw new RuntimeException("没有可用的微服务实例列表:"+serviceName);
        }
        String serviceIp = chooseTargetIp(serviceInstanceList);
        String source = serviceIp+reqPath;
        try {
            return new URI(source);
        } catch (URISyntaxException e) {
            log.error("根据source:{}构建URI异常",source);
        }
        return url;
    }
    /**
     * 方法实现说明:从服务列表中 随机选举一个ip
     * @param serviceInstanceList 服务列表
     * @return: 调用的ip
     * @exception:
     * @date:2020/2/6 13:15
     */
    private String chooseTargetIp(List<ServiceInstance> serviceInstanceList) {
        //采取随机的获取一个
        Random random = new Random();
        Integer randomIndex = random.nextInt(serviceInstanceList.size());
        String serviceIp = serviceInstanceList.get(randomIndex).getUri().toString();
        log.info("随机选举的服务IP:{}",serviceIp);
        return serviceIp;
    }
}

order服务的Controller：

package com.tuling.controller;
import com.tuling.entity.OrderInfo;
import com.tuling.entity.ProductInfo;
import com.tuling.mapper.OrderInfoMapper;
import com.tuling.vo.OrderVo;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;
/**
 * 自定义负载均衡的服务消费者
 */
@RestController
public class OrderInfoController {
    @Autowired
    private RestTemplate restTemplate;
    @Autowired
    private OrderInfoMapper orderInfoMapper;
    @RequestMapping("/selectOrderInfoById/{orderNo}")
    public Object selectOrderInfoById(@PathVariable("orderNo") String orderNo) {
        OrderInfo orderInfo = orderInfoMapper.selectOrderInfoById(orderNo);
        if(null == orderInfo) {
            return "根据orderNo:"+orderNo+"查询没有该订单";
        }
        ResponseEntity<ProductInfo> responseEntity = restTemplate.getForEntity("http://product-center/selectProductInfoById/"+orderInfo.getProductNo(), ProductInfo.class);
        ProductInfo productInfo = responseEntity.getBody();
        if(productInfo == null) {
            return "没有对应的商品";
        }
        OrderVo orderVo = new OrderVo();
        orderVo.setOrderNo(orderInfo.getOrderNo());
        orderVo.setUserName(orderInfo.getUserName());
        orderVo.setProductName(productInfo.getProductName());
        orderVo.setProductNum(orderInfo.getProductCount());
        return orderVo;
    }
}

在后端并行启动两个product实例：我们用 8081启动一个服务后，然后修改端口为8082，如下图所示勾选Allow parallel run，就可以同一个工程启动两个实例。

spring:
  datasource:
      druid:
        username: root
        password: 123456
        jdbcUrl: jdbc:mysql://192.168.1.14:3306/tuling-ms-alibaba?serverTimezone=Asia/Shanghai&useUnicode=true&characterEncoding=UTF-8&useSSL=false
        driverClassName: com.mysql.jdbc.Driver
        initialSize: 5
        minIdle: 5
        maxActive: 20
        maxWait: 60000
        timeBetweenEvictionRunsMillis: 60000
        minEvictableIdleTimeMillis: 300000
        validationQuery: SELECT 1 FROM DUAL
        testWhileIdle: true
        testOnBorrow: false
        testOnReturn: false
        poolPreparedStatements: true
        filters: stat,wall #\u914D\u7F6E\u8FC7\u6EE4\u5668
        maxPoolPreparedStatementPerConnectionSize: 20
        useGlobalDataSourceStat: true
        connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=500
  application:
    name: product-center
  cloud:
    nacos:
      discovery:
        server-addr: 192.168.1.5:8848
server:
  port: 8081
  #port: 8082

查看日志可以看到我们重写的负载均衡方法先从注册中心获取到product服务的列表，并且随机选择一个IP替换url。

2021-03-02 22:26:14.098  INFO 8449 --- [nio-8080-exec-9] com.tuling.config.TulingRestTemplate     : 请求的url路径为:http://product-center/selectProductInfoById/1
2021-03-02 22:26:14.098  INFO 8449 --- [nio-8080-exec-9] com.tuling.config.TulingRestTemplate     : 调用微服务的名称:product-center
2021-03-02 22:26:14.098  INFO 8449 --- [nio-8080-exec-9] com.tuling.config.TulingRestTemplate     : 请求path:/selectProductInfoById/1
2021-03-02 22:26:14.098  INFO 8449 --- [nio-8080-exec-9] com.tuling.config.TulingRestTemplate     : 随机选举的服务IP:http://192.168.1.136:8081
2021-03-02 22:26:14.098  INFO 8449 --- [nio-8080-exec-9] com.tuling.config.TulingRestTemplate     : 替换后的路径:http://192.168.1.136:8081/selectProductInfoById/1
2021-03-02 22:26:18.477  INFO 8449 --- [io-8080-exec-10] com.tuling.config.TulingRestTemplate     : 请求的url路径为:http://product-center/selectProductInfoById/1
2021-03-02 22:26:18.477  INFO 8449 --- [io-8080-exec-10] com.tuling.config.TulingRestTemplate     : 调用微服务的名称:product-center
2021-03-02 22:26:18.477  INFO 8449 --- [io-8080-exec-10] com.tuling.config.TulingRestTemplate     : 请求path:/selectProductInfoById/1
2021-03-02 22:26:18.478  INFO 8449 --- [io-8080-exec-10] com.tuling.config.TulingRestTemplate     : 随机选举的服务IP:http://192.168.1.136:8082
2021-03-02 22:26:18.478  INFO 8449 --- [io-8080-exec-10] com.tuling.config.TulingRestTemplate     : 替换后的路径:http://192.168.1.136:8082/selectProductInfoById/1

Ribbon组件使用

第一步：加入依赖（nacos-client和ribbon）

<!--加入nocas-client-->
<dependency>
   <groupId>com.alibaba.cloud</groupId>
   <artifactId>spring-cloud-alibaba-nacos-discovery</artifactId>
</dependency>
<!--加入ribbon-->
<dependency>
   <groupId>org.springframework.cloud</groupId>
   <artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
</dependency>

第二步：在RestTemplate上加上@LoadBalanced注册

package com.tuling.config;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.client.RestTemplate;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
@Configuration
public class WebConfig implements WebMvcConfigurer {
    @LoadBalanced
    @Bean
    public RestTemplate restTemplate( ) {
        return new RestTemplate();
    }
}

第三步：写配置文件（现在暂时用默认的ribbon负载均衡方法，配置文件只写nacos的就行）

spring:
  datasource:
      druid:
        username: root
        password: 123456
        jdbcUrl: jdbc:mysql://192.168.1.14:3306/tuling-ms-alibaba?serverTimezone=Asia/Shanghai&useUnicode=true&characterEncoding=UTF-8&useSSL=false
        driverClassName: com.mysql.jdbc.Driver
        initialSize: 5
        minIdle: 5
        maxActive: 20
        maxWait: 60000
        timeBetweenEvictionRunsMillis: 60000
        minEvictableIdleTimeMillis: 300000
        validationQuery: SELECT 1 FROM DUAL
        testWhileIdle: true
        testOnBorrow: false
        testOnReturn: false
        poolPreparedStatements: true
        filters: stat,wall #\u914D\u7F6E\u8FC7\u6EE4\u5668
        maxPoolPreparedStatementPerConnectionSize: 20
        useGlobalDataSourceStat: true
        connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=500
  cloud:
    nacos:
      discovery:
        server-addr: 192.168.1.5:8848
  application:
    name: order-center
server:
  port: 8080

第四步：写Controller

package com.tuling.controller;
import com.tuling.entity.OrderInfo;
import com.tuling.entity.ProductInfo;
import com.tuling.mapper.OrderInfoMapper;
import com.tuling.vo.OrderVo;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;
/**
 * 基于ribbon负载均衡
 */
@RestController
public class OrderInfoController {
    @Autowired
    private RestTemplate restTemplate;
    @Autowired
    private OrderInfoMapper orderInfoMapper;
    @RequestMapping("/selectOrderInfoById/{orderNo}")
    public Object selectOrderInfoById(@PathVariable("orderNo") String orderNo) {
        OrderInfo orderInfo = orderInfoMapper.selectOrderInfoById(orderNo);
        if(null == orderInfo) {
            return "根据orderNo:"+orderNo+"查询没有该订单";
        }
        ResponseEntity<ProductInfo> responseEntity = null;
        try {
            responseEntity = restTemplate.getForEntity("http://product-center/selectProductInfoById/"+orderInfo.getProductNo(), ProductInfo.class);
        }catch (Exception e) {
            System.out.println(e.getStackTrace());
        }
        ProductInfo productInfo = responseEntity.getBody();
        if(productInfo == null) {
            return "没有对应的商品";
        }
        OrderVo orderVo = new OrderVo();
        orderVo.setOrderNo(orderInfo.getOrderNo());
        orderVo.setUserName(orderInfo.getUserName());
        orderVo.setProductName(productInfo.getProductName());
        orderVo.setProductNum(orderInfo.getProductCount());
        return orderVo;
    }
}

和前面一样并行起2个product服务：

Ribbon细粒度自定义配置

场景：order服务需要采用随机算法调用product服务，使用轮询算法调用pay服务，其他服务使用随机算法调用。

在order服务的配置文件中指定即可：

spring:
  datasource:
      druid:
        username: root
        password: 123456
        jdbcUrl: jdbc:mysql://192.168.1.14:3306/tuling-ms-alibaba?serverTimezone=Asia/Shanghai&useUnicode=true&characterEncoding=UTF-8&useSSL=false
        driverClassName: com.mysql.jdbc.Driver
        initialSize: 5
        minIdle: 5
        maxActive: 20
        maxWait: 60000
        timeBetweenEvictionRunsMillis: 60000
        minEvictableIdleTimeMillis: 300000
        validationQuery: SELECT 1 FROM DUAL
        testWhileIdle: true
        testOnBorrow: false
        testOnReturn: false
        poolPreparedStatements: true
        filters: stat,wall #\u914D\u7F6E\u8FC7\u6EE4\u5668
        maxPoolPreparedStatementPerConnectionSize: 20
        useGlobalDataSourceStat: true
        connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=500
  cloud:
    nacos:
      discovery:
        server-addr: 192.168.1.5:8848
        #自定义负载均衡时使用
        cluster-name: NJ-CLUSTER
        metadata:
          current-version: V1
  application:
    name: order-center
#开启ribbon饥饿加载,解决微服务调用第一次很慢的情况下
ribbon:
  NFLoadBalancerRuleClassName: com.netflix.loadbalancer.RandomRule
  eager-load:
    enabled: true
    #可以指定多个微服务用逗号分隔
    clients: product-center,pay-center
#
##自定义Ribbon的细粒度配置
product-center:
  ribbon:
    NFLoadBalancerRuleClassName: com.netflix.loadbalancer.RandomRule
pay-center:
  ribbon:
    NFLoadBalancerRuleClassName: com.netflix.loadbalancer.RoundRobinRule
server:
  port: 8080

自定义负载均衡策略

order服务有V1一个版本，在NJ-Cluster（1个实例）；product服务有V1，V2两个版本分别在BJ-Cluster和NJ-Cluster（4个实例）。

要求order服务按照以下优先级调用product服务，跨版本不允许调用：

同集群同版本。
同版本不同集群。

package com.ribbonconfig;
import com.netflix.loadbalancer.IRule;
import com.tuling.myrule.TheSameClusterPriorityWithVersionRule;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
public class GlobalRibbonConfig {
    @Bean
    public IRule theSameClusterPriorityRule() {
        return new TheSameClusterPriorityWithVersionRule();  //自定义负载均衡策略
    }
}

编写自定义负载均衡策略TheSameClusterPriorityWithVersionRule，继承AbstractLoadBalancerRule并重写choose()方法:

package com.tuling.myrule;
import com.alibaba.cloud.nacos.NacosDiscoveryProperties;
import com.alibaba.cloud.nacos.ribbon.NacosServer;
import com.alibaba.nacos.api.exception.NacosException;
import com.alibaba.nacos.api.naming.NamingService;
import com.alibaba.nacos.api.naming.pojo.Instance;
import com.netflix.client.config.IClientConfig;
import com.netflix.loadbalancer.AbstractLoadBalancerRule;
import com.netflix.loadbalancer.BaseLoadBalancer;
import com.netflix.loadbalancer.Server;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.util.StringUtils;
import java.util.ArrayList;
import java.util.List;
/**
 * 自定义负载均衡，同集群同版本优先调用，然后是跨集群同版本
 */
@Slf4j
public class TheSameClusterPriorityWithVersionRule extends AbstractLoadBalancerRule {
    @Autowired
    private NacosDiscoveryProperties discoveryProperties;
    @Override
    public void initWithNiwsConfig(IClientConfig clientConfig) {
    }
    /**
     * 重写choose方法，自定义负载均衡策略
     * @param key
     * @return
     */
    @Override
    public Server choose(Object key) {
        try {
            //获取当前的集群名称
            String currentClusterName = discoveryProperties.getClusterName();
            //获取和当前集群 相同集群下,相同版本的 所有实例
            List<Instance> theSameClusterNameAndTheSameVersionInstList = getTheSameClusterAndTheSameVersionInstances(discoveryProperties);
            //声明被调用的实例
            Instance toBeChooseInstance;
            //判断同集群同版本号的微服务实例是否为空
            if(theSameClusterNameAndTheSameVersionInstList.isEmpty()) {
                //如果没有同集群同版本的服务，跨集群调用相同的版本
                toBeChooseInstance = crossClusterAndTheSameVersionInovke(discoveryProperties);
            }else {
                toBeChooseInstance = TulingWeightedBalancer.chooseInstanceByRandomWeight(theSameClusterNameAndTheSameVersionInstList);
                log.info("同集群同版本调用--->当前微服务所在集群:{},被调用微服务所在集群:{},当前微服务的版本:{},被调用微服务版本:{},Host:{},Port:{}",
                        currentClusterName,toBeChooseInstance.getClusterName(),discoveryProperties.getMetadata().get("current-version"),
                        toBeChooseInstance.getMetadata().get("current-version"),toBeChooseInstance.getIp(),toBeChooseInstance.getPort());
            }
            return new NacosServer(toBeChooseInstance);
        } catch (NacosException e) {
            log.error("同集群优先权重负载均衡算法选择异常:{}",e);
            return null;
        }
    }
    /**
     * 方法实现说明:获取相同集群下,相同版本的 所有实例
     * @param discoveryProperties nacos的配置
     * @return: List<Instance>
     * @exception: NacosException
     */
    private List<Instance> getTheSameClusterAndTheSameVersionInstances(NacosDiscoveryProperties discoveryProperties) throws NacosException {
        //当前的集群的名称
        String currentClusterName = discoveryProperties.getClusterName();
        String currentVersion = discoveryProperties.getMetadata().get("current-version");
        //获取所有实例的信息(包括不同集群的)
        List<Instance> allInstance =  getAllInstances(discoveryProperties);
        List<Instance> theSameClusterNameAndTheSameVersionInstList = new ArrayList<>();
        //过滤相同集群的
        for(Instance instance : allInstance) {
            if(StringUtils.endsWithIgnoreCase(instance.getClusterName(),currentClusterName)&&
               StringUtils.endsWithIgnoreCase(instance.getMetadata().get("current-version"),currentVersion)) {
                theSameClusterNameAndTheSameVersionInstList.add(instance);
            }
        }
        return theSameClusterNameAndTheSameVersionInstList;
    }
    /**
     * 方法实现说明:获取被调用服务的所有实例
     * @param discoveryProperties nacos的配置
     * @return: List<Instance>
     * @exception: NacosException
     */
    private List<Instance> getAllInstances(NacosDiscoveryProperties discoveryProperties) throws NacosException {
        //第1步:获取一个负载均衡对象
        BaseLoadBalancer baseLoadBalancer = (BaseLoadBalancer) getLoadBalancer();
        //第2步:获取当前调用的微服务的名称
        String invokedSerivceName = baseLoadBalancer.getName();
        //第3步:获取nacos clinet的服务注册发现组件的api
        NamingService namingService = discoveryProperties.namingServiceInstance();
        //第4步:获取所有的服务实例
        List<Instance> allInstance =  namingService.getAllInstances(invokedSerivceName);
        return allInstance;
    }
    /**
     * 方法实现说明:跨集群环境下 相同版本的
     * @param discoveryProperties
     * @return: List<Instance>
     * @exception: NacosException
     */
    private List<Instance> getCrossClusterAndTheSameVersionInstList(NacosDiscoveryProperties discoveryProperties) throws NacosException {
        //版本号
        String currentVersion = discoveryProperties.getMetadata().get("current-version");
        //被调用的所有实例
        List<Instance> allInstance = getAllInstances(discoveryProperties);
        List<Instance>  crossClusterAndTheSameVersionInstList = new ArrayList<>();
        //过滤相同版本
        for(Instance instance : allInstance) {
            if(StringUtils.endsWithIgnoreCase(instance.getMetadata().get("current-version"),currentVersion)) {
                crossClusterAndTheSameVersionInstList.add(instance);
            }
        }
        return crossClusterAndTheSameVersionInstList;
    }
    private Instance crossClusterAndTheSameVersionInovke(NacosDiscoveryProperties discoveryProperties) throws NacosException {
        //获取所有集群下相同版本的实例信息
        List<Instance>  crossClusterAndTheSameVersionInstList = getCrossClusterAndTheSameVersionInstList(discoveryProperties);
        //当前微服务的版本号
        String currentVersion = discoveryProperties.getMetadata().get("current-version");
        //当前微服务的集群名称
        String currentClusterName = discoveryProperties.getClusterName();
        //声明被调用的实例
        Instance toBeChooseInstance = null ;
        //没有对应相同版本的实例
        if(crossClusterAndTheSameVersionInstList.isEmpty()) {
            log.info("跨集群调用找不到对应合适的版本当前版本为:currentVersion:{}",currentVersion);
            throw new RuntimeException("找不到相同版本的微服务实例");
        }else {
            toBeChooseInstance = TulingWeightedBalancer.chooseInstanceByRandomWeight(crossClusterAndTheSameVersionInstList);
            log.info("跨集群同版本调用--->当前微服务所在集群:{},被调用微服务所在集群:{},当前微服务的版本:{},被调用微服务版本:{},Host:{},Port:{}",
                    currentClusterName,toBeChooseInstance.getClusterName(),discoveryProperties.getMetadata().get("current-version"),
                    toBeChooseInstance.getMetadata().get("current-version"),toBeChooseInstance.getIp(),toBeChooseInstance.getPort());
        }
        return toBeChooseInstance;
    }
}

RestTemplate添加@LoadBalanced注解：

package com.tuling.config;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.client.RestTemplate;
@Configuration
public class WebConfig {
    @LoadBalanced
    @Bean
    public RestTemplate restTemplate( ) {
        return new RestTemplate();
    }
}

order服务Controller方法和之前一样。

连续在浏览器请求order服务，在所有product服务都好的情况下，会优先调用同集群同版本的:

2021-03-04 23:42:20.492  INFO 9478 --- [nio-8080-exec-2] .m.TheSameClusterPriorityWithVersionRule : 同集群同版本调用--->当前微服务所在集群:NJ-CLUSTER,被调用微服务所在集群:NJ-CLUSTER,当前微服务的版本:V1,被调用微服务版本:V1,Host:192.168.1.136,Port:8081
2021-03-04 23:42:32.408  INFO 9478 --- [nio-8080-exec-4] .m.TheSameClusterPriorityWithVersionRule : 同集群同版本调用--->当前微服务所在集群:NJ-CLUSTER,被调用微服务所在集群:NJ-CLUSTER,当前微服务的版本:V1,被调用微服务版本:V1,Host:192.168.1.136,Port:8081
2021-03-04 23:42:33.029  INFO 9478 --- [nio-8080-exec-5] .m.TheSameClusterPriorityWithVersionRule : 同集群同版本调用--->当前微服务所在集群:NJ-CLUSTER,被调用微服务所在集群:NJ-CLUSTER,当前微服务的版本:V1,被调用微服务版本:V1,Host:192.168.1.136,Port:8081

将NJ-Cluster,V1版本的product服务下线，此时会去调BJ-Cluster的V1版本的服务：

2021-03-04 23:47:10.242  INFO 9478 --- [nio-8080-exec-8] .m.TheSameClusterPriorityWithVersionRule : 跨集群同版本调用--->当前微服务所在集群:NJ-CLUSTER,被调用微服务所在集群:BJ-CLUSTER,当前微服务的版本:V1,被调用微服务版本:V1,Host:192.168.1.136,Port:8083
2021-03-04 23:47:11.627  INFO 9478 --- [nio-8080-exec-9] .m.TheSameClusterPriorityWithVersionRule : 跨集群同版本调用--->当前微服务所在集群:NJ-CLUSTER,被调用微服务所在集群:BJ-CLUSTER,当前微服务的版本:V1,被调用微服务版本:V1,Host:192.168.1.136,Port:8083
2021-03-04 23:47:12.380  INFO 9478 --- [io-8080-exec-10] .m.TheSameClusterPriorityWithVersionRule : 跨集群同版本调用--->当前微服务所在集群:NJ-CLUSTER,被调用微服务所在集群:BJ-CLUSTER,当前微服务的版本:V1,被调用微服务版本:V1,Host:192.168.1.136,Port:8083

如果将NJ-Cluster,V1版本的product服务也下线，此时由于剩下的只有V2版本的product服务，将无法调用：

微服务客户端负载均衡组件Ribbon

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