spring cloud中通過配置文件自定義Ribbon負載均衡策略

一、Ribbon中的負載均衡策略

1、Ribbon中支持的負載均衡策略

AvailabilityFilteringRule：過濾掉那些因為一直連接失敗的被標記為circuit tripped的后端server，並過濾掉那些高並發的的后端server（active connections 超過配置的閾值） | 使用一個AvailabilityPredicate來包含過濾server的邏輯，其實就就是檢查status里記錄的各個server的運行狀態

RandomRule：隨機選擇一個server

BestAvailabl：選擇一個最小的並發請求的server，逐個考察Server，如果Server被tripped了，則忽略

RoundRobinRule：roundRobin方式輪詢選擇， 輪詢index，選擇index對應位置的server

WeightedResponseTimeRule：根據響應時間分配一個weight(權重)，響應時間越長，weight越小，被選中的可能性越低

RetryRule：對選定的負載均衡策略機上重試機制，在一個配置時間段內當選擇server不成功，則一直嘗試使用subRule的方式選擇一個可用的server

ZoneAvoidanceRule：復合判斷server所在區域的性能和server的可用性選擇server

ResponseTimeWeightedRule：作用同WeightedResponseTimeRule，二者作用是一樣的，ResponseTimeWeightedRule后來改名為WeightedResponseTimeRule

二、驗證

1、自定義負載均衡策略

 
            
            # 自定義負載均衡策略  
springboot-h2.ribbon.NFLoadBalancerRuleClassName=com.netflix.loadbalancer.RandomRule // 自定義使用隨機策略，springboot-h2是服務應用名

2、修改調用代碼

package com.chhliu.springboot.restful.controller;  
  
import org.springframework.beans.factory.annotation.Autowired;  
import org.springframework.cloud.client.ServiceInstance;  
import org.springframework.cloud.client.loadbalancer.LoadBalancerClient;  
import org.springframework.web.bind.annotation.GetMapping;  
import org.springframework.web.bind.annotation.PathVariable;  
import org.springframework.web.bind.annotation.RestController;  
import org.springframework.web.client.RestTemplate;  
  
import com.chhliu.springboot.restful.vo.User;  
  
@RestController  
public class RestTemplateController {  
    @Autowired  
    private RestTemplate restTemplate;  
      
    @Autowired  
    private LoadBalancerClient loadBalancerClient;  
      
    @GetMapping("/template/{id}")  
    public User findById(@PathVariable Long id) {  
        ServiceInstance serviceInstance = this.loadBalancerClient.choose("springboot-h2");  
        System.out.println("===" + ":" + serviceInstance.getServiceId() + ":" + serviceInstance.getHost() + ":"  
                + serviceInstance.getPort());// 打印當前調用服務的信息  
        User u = this.restTemplate.getForObject("http://springboot-h2/user/" + id, User.class);  
        System.out.println(u);  
        return u;  
    }  
}  

 

3、測試

 

服務調用關系如下：

測試結果如下：

 

 
            
            ===:springboot-h2:127.0.0.1:7902  
User [id=2, username=user2, name=李四, age=20, balance=100.00]  
===:springboot-h2:127.0.0.1:7901  
User [id=2, username=user2, name=李四, age=20, balance=100.00]  
===:springboot-h2:127.0.0.1:7902  
User [id=2, username=user2, name=李四, age=20, balance=100.00]  
===:springboot-h2:127.0.0.1:7901  
User [id=2, username=user2, name=李四, age=20, balance=100.00]  
===:springboot-h2:127.0.0.1:7902  
User [id=2, username=user2, name=李四, age=20, balance=100.00]  
===:springboot-h2:127.0.0.1:7902  
User [id=2, username=user2, name=李四, age=20, balance=100.00]  
===:springboot-h2:127.0.0.1:7902  
User [id=2, username=user2, name=李四, age=20, balance=100.00]  
===:springboot-h2:127.0.0.1:7902  
User [id=2, username=user2, name=李四, age=20, balance=100.00]  
===:springboot-h2:127.0.0.1:7902  
User [id=2, username=user2, name=李四, age=20, balance=100.00]  
===:springboot-h2:127.0.0.1:7901  
User [id=2, username=user2, name=李四, age=20, balance=100.00]  
===:springboot-h2:127.0.0.1:7901  
User [id=2, username=user2, name=李四, age=20, balance=100.00]  
===:springboot-h2:127.0.0.1:7902  
User [id=2, username=user2, name=李四, age=20, balance=100.00]  
===:springboot-h2:127.0.0.1:7902  
User [id=2, username=user2, name=李四, age=20, balance=100.00]  
===:springboot-h2:127.0.0.1:7901  
User [id=2, username=user2, name=李四, age=20, balance=100.00]  
===:springboot-h2:127.0.0.1:7901  
User [id=2, username=user2, name=李四, age=20, balance=100.00]  
發現選擇7901端口服務和7902端口服務確實是隨機的！