Ribbon的负载均衡算法
默认简单轮询算法:一台服务器一次
Ribbon在工作时分成两步
第一步先选择EurekaServer,它优先选择在同一个区域内负载较少的server;
第二步再根据用户指定的策略,在从server取到的服务注册列表中选择一个地址;
参考microservicecloud-provider-dept-8001,新建两份,分别命名为8002,8003
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>com.yt.springcloud</groupId>
<artifactId>microservicecloud</artifactId>
<version>0.0.1-SNAPSHOT</version>
</parent>
<artifactId>microservicecloud-provider-dept-8002</artifactId>
<dependencies>
<!-- 引入自己已定义的api通用包,可以使用Dept部门Entity -->
<dependency>
<groupId>com.yt.springcloud</groupId>
<artifactId>microservicecloud-api</artifactId>
<version>${project.version}</version>
</dependency>
<!-- junit的jar包 -->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
</dependency>
<!-- mysql的jar包 -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
</dependency>
<!-- druid的jar包 -->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
</dependency>
<!-- mybatis的整合 -->
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
</dependency>
<!-- springboot的整合jetty 微服务架构不发布在tomcat下面,内嵌的父容器 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jetty</artifactId>
</dependency>
<!-- springboot的整合web-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<!-- springboot的整合测试 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
</dependency>
<!-- 修改后立即生效,热部署 (一修改,自动发布,自动构建)-->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>springloaded</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
</dependency>
<!-- 将微服务provider侧注册进入eureka(引入eureka的client端) -->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-config</artifactId>
</dependency>
<!-- actuator监控信息完善 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
</dependencies>
</project>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>com.yt.springcloud</groupId>
<artifactId>microservicecloud</artifactId>
<version>0.0.1-SNAPSHOT</version>
</parent>
<artifactId>microservicecloud-provider-dept-8003</artifactId>
<dependencies>
<!-- 引入自己已定义的api通用包,可以使用Dept部门Entity -->
<dependency>
<groupId>com.yt.springcloud</groupId>
<artifactId>microservicecloud-api</artifactId>
<version>${project.version}</version>
</dependency>
<!-- junit的jar包 -->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
</dependency>
<!-- mysql的jar包 -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
</dependency>
<!-- druid的jar包 -->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
</dependency>
<!-- mybatis的整合 -->
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
</dependency>
<!-- springboot的整合jetty 微服务架构不发布在tomcat下面,内嵌的父容器 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jetty</artifactId>
</dependency>
<!-- springboot的整合web-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<!-- springboot的整合测试 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
</dependency>
<!-- 修改后立即生效,热部署 (一修改,自动发布,自动构建)-->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>springloaded</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
</dependency>
<!-- 将微服务provider侧注册进入eureka(引入eureka的client端) -->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-config</artifactId>
</dependency>
<!-- actuator监控信息完善 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
</dependencies>
</project>
新建8002/8003数据库,各自微服务分别连接各自的数据库
DROP DATABASE IF EXISTS cloudDB02;
CREATE DATABASE cloudDB02 CHARACTER SET UTF8;
USE cloudDB02;
CREATE TABLE dept(
deptno BIGINT NOT NULL PRIMARY KEY AUTO_INCREMENT,
dname VARCHAR(60),
db_source VARCHAR(60)
);
INSERT INTO dept(dname,db_source)VALUES ('开发部',DATABASE());
INSERT INTO dept(dname,db_source)VALUES ('人事部',DATABASE());
INSERT INTO dept(dname,db_source)VALUES ('财务部',DATABASE());
INSERT INTO dept(dname,db_source)VALUES ('市场部',DATABASE());
INSERT INTO dept(dname,db_source)VALUES ('运维部',DATABASE());
SELECT * FROM dept;
DROP DATABASE IF EXISTS cloudDB03;
CREATE DATABASE cloudDB03 CHARACTER SET UTF8;
USE cloudDB03;
CREATE TABLE dept(
deptno BIGINT NOT NULL PRIMARY KEY AUTO_INCREMENT,
dname VARCHAR(60),
db_source VARCHAR(60)
);
INSERT INTO dept(dname,db_source)VALUES ('开发部',DATABASE());
INSERT INTO dept(dname,db_source)VALUES ('人事部',DATABASE());
INSERT INTO dept(dname,db_source)VALUES ('财务部',DATABASE());
INSERT INTO dept(dname,db_source)VALUES ('市场部',DATABASE());
INSERT INTO dept(dname,db_source)VALUES ('运维部',DATABASE());
SELECT * FROM dept;
修改8002的yml
server:
port: 8002 # 当前微服务的端口
mybatis:
config-location: classpath:mybatis/mybatis.cfg.xml # mybatis配置文件所在路径
type-aliases-package: com.yt.springcloud.entity # 所有饿entity实体类所在包
mapper-locations:
- classpath:mybatis/mapper/**/*.xml # mapper映射文件
spring:
application:
name: microservicecloud-dept # 对外暴露的微服务的名字(很重要)
datasource:
type: com.alibaba.druid.pool.DruidDataSource # 当前数据源操作类型
driver-class-name: org.gjt.mm.mysql.Driver # mysql驱动包
url: jdbc:mysql://localhost:3306/cloudDB02 # 数据库名称
username: root
password: hannong
dbcp2:
min-idle: 5 # 数据库连接池的最小维持连接数
initial-size: 5 # 初始化连接数
max-total: 5 # 最大连接数
max-wait-millis: 200 # 等待连接获取的最大超时时间
eureka:
client: #客户端注册进eureka服务列表内
service-url:
defaultZone: http://eureka7001.com:7001/eureka/,http://eureka7002.com:7002/eureka/,http://eureka7003.com:7003/eureka/ #去注册中心的地址
#defaultZone:7001,7002,7003 去注册中心的地址
instance:
instance-id: microservicecloud-dept8002 #修改eureka的服务路径名称
prefer-ip-address: true #访问路径可以显示ip地址
info:
app.name: yt-microservicecloud #
company.name: www.yt.com #
build.artifactId: $project.artifactId$ #
build.version: $project.version$ #
修改8003的yml
server:
port: 8003 # 当前微服务的端口
mybatis:
config-location: classpath:mybatis/mybatis.cfg.xml # mybatis配置文件所在路径
type-aliases-package: com.yt.springcloud.entity # 所有饿entity实体类所在包
mapper-locations:
- classpath:mybatis/mapper/**/*.xml # mapper映射文件
spring:
application:
name: microservicecloud-dept # 对外暴露的微服务的名字(很重要)
datasource:
type: com.alibaba.druid.pool.DruidDataSource # 当前数据源操作类型
driver-class-name: org.gjt.mm.mysql.Driver # mysql驱动包
url: jdbc:mysql://localhost:3306/cloudDB03 # 数据库名称
username: root
password: hannong
dbcp2:
min-idle: 5 # 数据库连接池的最小维持连接数
initial-size: 5 # 初始化连接数
max-total: 5 # 最大连接数
max-wait-millis: 200 # 等待连接获取的最大超时时间
eureka:
client: #客户端注册进eureka服务列表内
service-url:
defaultZone: http://eureka7001.com:7001/eureka/,http://eureka7002.com:7002/eureka/,http://eureka7003.com:7003/eureka/ #去注册中心的地址
#defaultZone:7001,7002,7003 去注册中心的地址
instance:
instance-id: microservicecloud-dept8003 #修改eureka的服务路径名称
prefer-ip-address: true #访问路径可以显示ip地址
info:
app.name: yt-microservicecloud #
company.name: www.yt.com #
build.artifactId: $project.artifactId$ #
build.version: $project.version$ #
启动3个eureka集群配置区
启动3个Dept微服务并各自测试通过
启动microservicecloud-consumer-dept-80:http://localhost:8003/dept/list
客户端通过Ribbon完成负载均衡并访问上一步的Dept微服务
总结:Ribbon其实就是一个软负载均衡的客户端组件,它可以和其他所需请求的客户端结合使用,和eureka结合只是其中的一个实例;
Ribbon核心组件IRule:根据特定算法中从服务列表中选取一个要访问的服务;
默认的简单轮询算法,改成随机算法
package com.yt.springcloud.cfgbeans;
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 com.netflix.loadbalancer.IRule;
import com.netflix.loadbalancer.RandomRule;
@Configuration//其实就是ApplicationContext.xml
public class ConfigBean {
/**
* RestTemplate提供了多种便捷访问远程Http服务的方法
* 是一种简单便捷的访问restful服务模板类,是Spring提供的用于访问Rest服务的客户端模板工具集
* @return
*/
@Bean
@LoadBalanced//ribbon是客户端的负载均衡工具,所以在rest去访问微服务的时候,自带负载均衡,这个注解是开启负载均衡的
public RestTemplate getRestTemplate() {
return new RestTemplate();
}
/**
* 有显示的声明算法,就覆盖默认的轮询算法
* @return
*/
@Bean
public IRule myRule() {
//return new RoundRobinRule();//轮询算法
return new RandomRule();//随机算法
}
}
Ribbon自定义算法
修改microservicecloud-consumer-dept-80
主启动类添加@RibbonClient
package com.yt.springcloud;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.netflix.ribbon.RibbonClient;
import com.yt.myrule.MySelfRule;
@SpringBootApplication
@EnableEurekaClient
//在启动该微服务的时候就能去加载我们的自定义Ribbon配置类，从而使配置生效
@RibbonClient(name="MICROSERVICECLOUD-DEPT",configuration=MySelfRule.class)
public class DeptConsumer80_App {
public static void main(String[] args) {
SpringApplication.run(DeptConsumer80_App.class, args);
}
}
注意配置细节
package com.yt.myrule;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import com.netflix.loadbalancer.IRule;
import com.netflix.loadbalancer.RandomRule;
//自定义负载均衡算法类
@Configuration
public class MySelfRule {
@Bean
public IRule myRule() {
return new RandomRule();//Ribbon默认是轮询,我自定义为随机
}
}
启动3个eureka集群和8001,8002,8003,80等
自定义规则深度解析
创建RandomRule_YT
package com.yt.myrule;
import java.util.List;
import com.netflix.client.config.IClientConfig;
import com.netflix.loadbalancer.AbstractLoadBalancerRule;
import com.netflix.loadbalancer.ILoadBalancer;
import com.netflix.loadbalancer.Server;
public class RandomRule_YT extends AbstractLoadBalancerRule{
// total = 0 // 当total==5以后，我们指针才能往下走，
// index = 0 // 当前对外提供服务的服务器地址，
// total需要重新置为零，但是已经达到过一个5次，我们的index = 1
// 分析：我们5次，但是微服务只有8001 8002 8003 三台，OK？
//
private int total = 0; // 总共被调用的次数，目前要求每台被调用5次
private int currentIndex = 0; // 当前提供服务的机器号
/**
* 返回具体服务的服务器(是8001还是8002还是8003)
* @param lb
* @param key
* @return
*/
public Server choose(ILoadBalancer lb, Object key)
{
if (lb == null) {
return null;
}
Server server = null;
while (server == null) {
if (Thread.interrupted()) {
return null;
}
List<Server> upList = lb.getReachableServers();//活着的,可以对外提供服务的服务器
List<Server> allList = lb.getAllServers();
int serverCount = allList.size();//得到服务器的台数
if (serverCount == 0) {//为0就不进去
/*
* No servers. End regardless of pass, because subsequent passes only get more
* restrictive.
*/
return null;
}
// int index = rand.nextInt(serverCount);// java.util.Random().nextInt(3);
// server = upList.get(index);
// private int total = 0; // 总共被调用的次数，目前要求每台被调用5次
// private int currentIndex = 0; // 当前提供服务的机器号
if(total < 5)
{
server = upList.get(currentIndex);
total++;
}else {
total = 0;
currentIndex++;
if(currentIndex >= upList.size())
{
currentIndex = 0;
}
}
if (server == null) {
/*
* The only time this should happen is if the server list were somehow trimmed.
* This is a transient condition. Retry after yielding.
*/
Thread.yield();
continue;
}
if (server.isAlive()) {
return (server);
}
// Shouldn't actually happen.. but must be transient or a bug.
server = null;
Thread.yield();
}
return server;
}
@Override
public Server choose(Object key)
{
return choose(getLoadBalancer(), key);
}
@Override
public void initWithNiwsConfig(IClientConfig clientConfig)
{
// TODO Auto-generated method stub
}
}
修改MySelfRule类的返回类
package com.yt.myrule;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import com.netflix.loadbalancer.IRule;
//自定义负载均衡算法类
@Configuration
public class MySelfRule {
@Bean
public IRule myRule() {
return new RandomRule_YT();//Ribbon默认是轮询,我自定义为随机
}
}
启动3个eureka集群,8001,8002,8003,80等
总结
翻译于尚硅谷周阳老师:https://www.bilibili.com/video/av22613028?from=search&seid=11377756339718254280
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