0. Dubbo简易介绍
DUBBO是一个分布式服务框架,致力于提供高性能和透明化的RPC远程服务调用方案,是阿里巴巴SOA服务化治理方案的核心框架,每天为2,000+个服务提供3,000,000,000+次访问量支持,并被广泛应用于阿里巴巴集团的各成员站点。
1. 架构演变
- 单一应用架构
- 当网站流量很小时,只需一个应用,将所有功能都部署在一起,以减少部署节点和成本。
- 此时,用于简化增删改查工作量的 数据访问框架(ORM) 是关键。
- 垂直应用架构
- 当访问量逐渐增大,单一应用增加机器带来的加速度越来越小,将应用拆成互不相干的几个应用,以提升效率。
- 此时,用于加速前端页面开发的 Web框架(MVC) 是关键。
- 分布式服务架构
- 当垂直应用越来越多,应用之间交互不可避免,将核心业务抽取出来,作为独立的服务,逐渐形成稳定的服务中心,使前端应用能更快速的响应多变的市场需求。
- 此时,用于提高业务复用及整合的 分布式服务框架(RPC) 是关键。
- 流动计算架构
- 当服务越来越多,容量的评估,小服务资源的浪费等问题逐渐显现,此时需增加一个调度中心基于访问压力实时管理集群容量,提高集群利用率。
- 此时,用于提高机器利用率的 资源调度和治理中心(SOA) 是关键。
2. 常见问题
在大规模服务化之前,应用可能只是通过RMI或Hessian等工具,简单的暴露和引用远程服务,通过配置服务的URL地址进行调用,通过F5等硬件进行负载均衡。
(1) 当服务越来越多时,服务URL配置管理变得非常困难,F5硬件负载均衡器的单点压力也越来越大。
此时需要一个服务注册中心,动态的注册和发现服务,使服务的位置透明。
并通过在消费方获取服务提供方地址列表,实现软负载均衡和Failover,降低对F5硬件负载均衡器的依赖,也能减少部分成本。
(2) 当进一步发展,服务间依赖关系变得错踪复杂,甚至分不清哪个应用要在哪个应用之前启动,架构师都不能完整的描述应用的架构关系。
这时,需要自动画出应用间的依赖关系图,以帮助架构师理清理关系。
(3) 接着,服务的调用量越来越大,服务的容量问题就暴露出来,这个服务需要多少机器支撑?什么时候该加机器?
为了解决这些问题,第一步,要将服务现在每天的调用量,响应时间,都统计出来,作为容量规划的参考指标。
其次,要可以动态调整权重,在线上,将某台机器的权重一直加大,并在加大的过程中记录响应时间的变化,直到响应时间到达阀值,记录此时的访问量,再以此访问量乘以机器数反推总容量。
3. Dubbo简易项目
3.1 项目结构:
dubbo-parent :所有项目的父项目,统一管理依赖等
dubbo-api:提供对外暴露的API服务
dubbo-provider:服务的生产者,提供对API的实现
dubbo-consumer:服务的消费者,
3.2 pom.xml
<properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <!-- frameworks --> <org.springframework.version>3.2.4.RELEASE</org.springframework.version> </properties> <dependencyManagement> <dependencies> <dependency> <groupId>commons-io</groupId> <artifactId>commons-io</artifactId> <version>2.0.1</version> </dependency> <dependency> <groupId>org.apache.commons</groupId> <artifactId>commons-lang3</artifactId> <version>3.1</version> </dependency> <dependency> <groupId>commons-logging</groupId> <artifactId>commons-logging</artifactId> <version>1.1.3</version> </dependency> <dependency> <groupId>org.jboss.netty</groupId> <artifactId>netty</artifactId> <version>3.2.5.Final</version> </dependency> <dependency> <groupId>javassist</groupId> <artifactId>javassist</artifactId> <version>3.12.1.GA</version> </dependency> <dependency> <groupId>log4j</groupId> <artifactId>log4j</artifactId> <version>1.2.17</version> </dependency> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-api</artifactId> <version>1.7.5</version> </dependency> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-log4j12</artifactId> <version>1.6.6</version> </dependency> <dependency> <groupId>com.alibaba</groupId> <artifactId>dubbo</artifactId> <!-- <version>2.5.4-SNAPSHOT</version> --> <version>2.5.3</version> </dependency> <dependency> <groupId>org.apache.zookeeper</groupId> <artifactId>zookeeper</artifactId> <version>3.3.3</version> </dependency> <dependency> <groupId>com.101tec</groupId> <artifactId>zkclient</artifactId> <version>0.3</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-aop</artifactId> <version>${org.springframework.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-aspects</artifactId> <version>${org.springframework.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-beans</artifactId> <version>${org.springframework.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context</artifactId> <version>${org.springframework.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context-support</artifactId> <version>${org.springframework.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-core</artifactId> <version>${org.springframework.version}</version> </dependency> </dependencies> </dependencyManagement>
3.2 定义接口
在dubbo-api项目中暴露对外提供的服务接口(API):
/** * * 测试接口 * * @author night */ public interface HelloService { void echo(String str); }
3.3 注册生产者服务
编辑dubbo-provider项目的pom.xml文件,引入dubbo-api项目:
<dependencies> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.11</version> <scope>test</scope> </dependency> <dependency> <groupId>org.luisyang</groupId> <artifactId>dubbo-api</artifactId> <version>0.0.1-SNAPSHOT</version> </dependency> <dependency> <groupId>org.luisyang.dubbo</groupId> <artifactId>dubbo-api</artifactId> <version>0.0.1-SNAPSHOT</version> </dependency> <!-- dubbo 需要的jar start --> <dependency> <groupId>org.jboss.netty</groupId> <artifactId>netty</artifactId> </dependency> <dependency> <groupId>com.alibaba</groupId> <artifactId>dubbo</artifactId> <exclusions> <exclusion> <groupId>org.springframework</groupId> <artifactId>spring</artifactId> </exclusion> </exclusions> </dependency> <dependency> <groupId>org.apache.zookeeper</groupId> <artifactId>zookeeper</artifactId> </dependency> <dependency> <groupId>com.101tec</groupId> <artifactId>zkclient</artifactId> </dependency> <!-- dubbo 需要的jar end --> <dependency> <groupId>commons-io</groupId> <artifactId>commons-io</artifactId> </dependency> <dependency> <groupId>org.apache.commons</groupId> <artifactId>commons-lang3</artifactId> </dependency> <dependency> <groupId>commons-logging</groupId> <artifactId>commons-logging</artifactId> </dependency> <dependency> <groupId>log4j</groupId> <artifactId>log4j</artifactId> </dependency> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-api</artifactId> </dependency> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-log4j12</artifactId> </dependency> <!-- Common Dependency End --> <!-- Spring Dependency Begin --> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-beans</artifactId> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context</artifactId> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context-support</artifactId> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-core</artifactId> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-aop</artifactId> <scope>compile</scope> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-aspects</artifactId> <scope>compile</scope> </dependency> <!-- Spring Dependency End --> </dependencies>
添加接口实现:
public class HelloServiceImpl implements HelloService{ public void echo(String str) { // TODO Auto-generated method stub System.out.println("Hello " +str +" !!!!!"); } }
添加服务配置文件:
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:dubbo="http://code.alibabatech.com/schema/dubbo" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd http://code.alibabatech.com/schema/dubbo http://code.alibabatech.com/schema/dubbo/dubbo.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd"> <!-- 读入配置属性文件 --> <bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer"> <property name="ignoreResourceNotFound" value="false" /> <property name="ignoreUnresolvablePlaceholders" value="true" /> <property name="locations"> <list> <value>file:conf/*.properties</value> </list> </property> </bean> <dubbo:provider> <dubbo:parameter key="shutdown.timeout" value="10000" /> <!-- 单位毫秒 --> </dubbo:provider> <!-- owner应用或者服务的负责人 --> <dubbo:application name="demo-provider" owner=""/> <!-- 建议将internal配置放到公共配置文件中 --> <dubbo:registry id="internal" protocol="${dubbo.registry.internal.protocol}" address="${dubbo.registry.internal.address}" /> <dubbo:registry id="external" protocol="${dubbo.registry.external.protocol}" address="${dubbo.registry.internal.address}" /> <!-- 大文件传输,协议选择rmi --> <dubbo:protocol name="rmi" port="1099" accesslog="log/access.log" /> <dubbo:protocol name="dubbo" port="20880" accesslog="true"> <dubbo:parameter key="shutdown.timeout" value="10000" /> <!-- 单位毫秒 --> </dubbo:protocol> <bean id="helloService" class="org.luisyang.dubbo.api.impl.HelloServiceImpl" /> <!-- 当consumer发现所有服务不可用时,mock的使用场景 <provider delay="-1" /> 当spring容器有依赖,需要 <protocol/service/reference timeout="1000" 默认1000ms, 复杂/阻塞时间比较长的服务可以加大 --> <dubbo:service interface="org.luisyang.dubbo.api.HelloService" ref="helloService" protocol="dubbo" registry="internal" /> <!-- internal暴露给内部的,external是暴露给外部的(比如网银) --> <!-- <dubbo:service interface="com.alibaba.dubbo.demo.DemoService" ref="demoService" protocol="rmi" registry="internal" /> --> </beans>
添加日志配置文件:
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE log4j:configuration SYSTEM "log4j.dtd"> <log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/" debug="false"> <appender name="FIlE_LOG" class="org.apache.log4j.RollingFileAppender"> <param name="File" value="log/provider.log" /> <param name="Append" value="true" /> <param name="MaxFileSize" value="15000KB" /> <param name="MaxBackupIndex" value="100"/> <param name="encoding" value="UTF-8"/> <layout class="org.apache.log4j.PatternLayout"> <param name="ConversionPattern" value="[%d{dd/MM/yy hh:mm:ss:sss z}] %t %5p %c{2}: %m%n" /> </layout> </appender> <appender name="CONSOLE" class="org.apache.log4j.ConsoleAppender"> <layout class="org.apache.log4j.PatternLayout"> <param name="ConversionPattern" value="[%d{dd/MM/yy hh:mm:ss:sss z}] %t %5p %c{2}: %m%n" /> </layout> </appender> <root> <level value="INFO" /> <appender-ref ref="CONSOLE" /> <appender-ref ref="FIlE_LOG" /> </root> </log4j:configuration>
添加属性配置文件(dubbo-rpc.properties):
dubbo.registry.internal.protocol=zookeeper dubbo.registry.external.protocol=zookeeper dubbo.registry.internal.address=192.168.91.132:2181 dubbo.registry.external.address=192.168.91.132:2181
dubbo.provider.servcie.version=1.0.0
添加属性配置文件(dubbo.properties):
dubbo.container=log4j,spring dubbo.application.name=demo-provider dubbo.application.owner=william dubbo.shutdown.hook=true #dubbo.registry.address=multicast://224.5.6.7:1234 #dubbo.registry.address=zookeeper://127.0.0.1:2181 #dubbo.registry.address=redis://127.0.0.1:6379 #dubbo.registry.address=dubbo://127.0.0.1:9090 #dubbo.monitor.protocol=registry dubbo.protocol.name=dubbo dubbo.protocol.port=20880 #dubbo.protocol.host=192.168.116.1 dubbo.service.loadbalance=roundrobin #dubbo.log4j.file=logs/dubbo-demo-consumer.log #dubbo.log4j.level=WARN
添加测试类:
/** * * 发布服务 * * @author night */ public class ProviderTest { public static void main(String[] args) throws Exception { ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("springContext.xml"); context.start(); System.in.read(); } }
3.5 注册服务消费者
同上服务生产者,pom文件中引入dubbo-api的依赖
日志配置文件也同上。
添加服务配置文件:
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:dubbo="http://code.alibabatech.com/schema/dubbo" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd http://code.alibabatech.com/schema/dubbo http://code.alibabatech.com/schema/dubbo/dubbo.xsd"> <!-- 读入配置属性文件 --> <bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer"> <property name="ignoreResourceNotFound" value="false" /> <property name="ignoreUnresolvablePlaceholders" value="true" /> <property name="locations"> <list> <value>file:conf/*.properties</value> </list> </property> </bean> <dubbo:application name="demo-consumer" /> <dubbo:consumer timeout="100000" /> <dubbo:registry protocol="zookeeper" address="${dubbo.registry.address}" /> <dubbo:reference id="helloService" interface="org.luisyang.dubbo.api.HelloService" protocol="dubbo" check="false"/> </beans>
添加服务属性配置文件(dubbo.properties):
dubbo.container=log4j,spring dubbo.application.name=demo-consumer dubbo.application.owner=william #dubbo.registry.address=multicast://224.5.6.7:1234 #dubbo.registry.address=localhost:2181 dubbo.registry.address=192.168.91.132:2181 #dubbo.registry.address=redis://127.0.0.1:6379 #dubbo.registry.address=dubbo://127.0.0.1:9090 #dubbo.monitor.protocol=registry dubbo.protocol.name=dubbo dubbo.protocol.port=20880 dubbo.service.loadbalance=roundrobin dubbo.consumer.ref.version=1.0
添加消费服务测试类:
/** * * 消费服务 * * @author night */ public class ConsumerTest { public static void main(String[] args) throws Exception { ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("springContext.xml"); context.start(); HelloService helloService = (HelloService) context.getBean("helloService"); int i = 1; while(true){ helloService.echo("word"+i); Thread.sleep(1000); i ++; } } }
3.6 注册中心
由于Dubbo启动需要到第三方的注册中心查询/注册服务信息。(本示例中采用的是Zookeeper。)
Linux下简易搭建单节点的Zookeeper服务。
下载地址:
http://mirrors.cnnic.cn/apache/zookeeper/
将Zookeeper安装拷贝至远程服务器中。
[root]# tar –zxvf zookeeper-3.4.6.tar.gz
[root]# mv zookeeper-3.4.6 zookeeper
[root]# cd zookeeper
[root]# touch conf/zoo.cfg
[root]# vi conf/zoo.cfg
拷贝如下内容:
tickTime=2000 initLimit=10 syncLimit=5 dataDir=/opt/zookeeper/data dataLogDir=/opt/zookeeper/logs clientPort=2181
启动Zookeeper服务:
[root]# ./bin/zkServer.sh start
查看服务状态:
[root]# ./bin/zkServer.sh status
停止服务:
[root]# ./bin/zkServer.sh stop
3.7 测试:
运行ProviderTest.java 将服务注册到服务中心。
运行ConsumerTest.java消费服务。
4.参考资料
Dubbo官网:
用户指南:
http://dubbo.io/User+Guide-zh.htm
Zookeeper官网:
Dubbo与Zookeeper、SpringMVC整合和使用(负载均衡、容错):
http://doc.okbase.net/congcong68/archive/112508.html
5.示例下载