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提示:本文主要对Eureka的集群搭建进行总结
提示:这里可以添加本文要记录的大概内容:
本文主要对Eureka的集群搭建进行总结
提示:以下是本篇文章正文内容
问题:微服务RPC远程服务调用最核心的是什么?
高可用,试想你的注册中心只有一个only one, 它出故障了那就呵呵( ̄▽ ̄)"了,会导致整个为服务环境不可用,所以解决办法:搭建Eureka注册中心集群 ,实现负载均衡+故障容错
参考cloud-eureka-server7001,新建cloud-eureka-server7002
<?xml version="1.0" encoding="UTF-8"?> <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"> <parent> <artifactId>cloud2022</artifactId> <groupId>com.atguidu.springcloud</groupId> <version>1.0-SNAPSHOT</version> </parent> <modelVersion>4.0.0</modelVersion> <artifactId>cloud-eureka-server7002</artifactId> <dependencies> <!--euraka server--> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId> </dependency> <dependency><!--引入自定义的api通用包--> <groupId>com.atguidu.springcloud</groupId> <artifactId>cloud-api-commons</artifactId> <version>${project.version}</version> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-actuator</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-devtools</artifactId> <scope>runtime</scope> <optional>true</optional> </dependency> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <optional>true</optional> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> </dependency> </dependencies> </project>
父工程会默认将当前创建的项目依赖引入
父工程的pom文件:
<modules>
<module>cloud-provider-payment8001</module>
<module>cloud-consumer-order80</module>
<module>cloud-api-commons</module>
<module>cloud-euraka-server7001</module>
<module>cloud-eureka-server7002</module>
</modules>
找到C:\Windows\System32\drivers\etc路径下的hosts文件,修改映射配置添加进hosts文件
### eureka ###
127.0.0.1 eureka7001.com
127.0.0.1 eureka7002.com
application.yml
server:
port: 7001
eureka:
instance:
hostname: localhost
client:
register-with-eureka: false #false表示不向注册中心注册自己
fetch-registry: false #表示自己就是注册中心,职责就是维护服务实例,并不需要去检索服务
#设置Eureka Server交互的地址,查询服务和注册服务都需要依赖这个地址
service-url:
defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/
7001:
server:
port: 7001
eureka:
instance:
hostname: eureka7001.com #eureka服务端的实例名称
client:
register-with-eureka: false #false表示不向注册中心注册自己。
fetch-registry: false #false表示自己端就是注册中心,我的职责就是维护服务实例,并不需要去检索服务
service-url:
defaultZone: http://eureka7002.com:7002/eureka/
7002:
server:
port: 7002
eureka:
instance:
hostname: eureka7002.com #eureka服务端的实例名称
client:
register-with-eureka: false #false表示不向注册中心注册自己。
fetch-registry: false #false表示自己端就是注册中心,我的职责就是维护服务实例,并不需要去检索服务
service-url:
defaultZone: http://eureka7001.com:7001/eureka/
package com.atguigu.springcloud;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;
@SpringBootApplication
@EnableEurekaServer
public class EurekaMain7002 {
public static void main(String[] args) {
SpringApplication.run(EurekaMain7002.class, args);
}
}
http://eureka7001.com:7001/
http://eureka7002.com:7002/
# 集群版
defaultZone: http://eureka7001.com:7001/eureka,http://eureka7002.com:7002/eureka
application.yml:
server: port: 8001 spring: application: name: cloud-payment-service datasource: type: com.alibaba.druid.pool.DruidDataSource # 当前数据源操作类型 driver-class-name: com.mysql.cj.jdbc.Driver # mysql驱动包 com.mysql.jdbc.Driver url: jdbc:mysql://localhost:3306/springcloud2021?useUnicode=true&characterEncoding=utf-8&useSSL=false username: root password: 123456 eureka: client: #表示是否将自己注册进EurekaServer默认为true。 register-with-eureka: true #是否从EurekaServer抓取已有的注册信息,默认为true。单节点无所谓,集群必须设置为true才能配合ribbon使用负载均衡 fetchRegistry: true service-url: #defaultZone: http://localhost:7001/eureka defaultZone: http://eureka7001.com:7001/eureka,http://eureka7002.com:7002/eureka # 集群版 mybatis: mapperLocations: classpath:mapper/*.xml type-aliases-package: com.atguigu.springcloud.entities # 所有Entity别名类所在包
defaultZone: http://eureka7001.com:7001/eureka,http://eureka7002.com:7002/eureka # 集群版
application.yml:
server: port: 80 spring: application: name: cloud-order-service eureka: client: #表示是否将自己注册进EurekaServer默认为true。 register-with-eureka: true #是否从EurekaServer抓取已有的注册信息,默认为true。单节点无所谓,集群必须设置为true才能配合ribbon使用负载均衡 fetchRegistry: true service-url: defaultZone: http://eureka7001.com:7001/eureka,http://eureka7002.com:7002/eureka # 集群版
先要启动EurekaServer,7001/7002服务,再要启动服务提供者provide——8001,最后再启动消费者——80
http://localhost/consumer/payment/get/1
参考cloud-provider-payment8001
pom.xml
<?xml version="1.0" encoding="UTF-8"?> <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"> <parent> <artifactId>cloud2022</artifactId> <groupId>com.atguidu.springcloud</groupId> <version>1.0-SNAPSHOT</version> </parent> <modelVersion>4.0.0</modelVersion> <artifactId>cloud-provider-payment8002</artifactId> <dependencies> <!--eureka-client--> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId> </dependency> <dependency> <groupId>com.atguidu.springcloud</groupId> <artifactId>cloud-api-commons</artifactId> <version>${project.version}</version> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-actuator</artifactId> </dependency> <dependency> <groupId>org.mybatis.spring.boot</groupId> <artifactId>mybatis-spring-boot-starter</artifactId> </dependency> <dependency> <groupId>com.alibaba</groupId> <artifactId>druid-spring-boot-starter</artifactId> <version>1.1.10</version> </dependency> <!--mysql-connector-java--> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> </dependency> <!--jdbc--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-jdbc</artifactId> </dependency> <!--热部署--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-devtools</artifactId> <scope>runtime</scope> <optional>true</optional> </dependency> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <optional>true</optional> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> </dependencies> </project>
application.yml
server: port: 8002 spring: application: name: cloud-payment-service datasource: type: com.alibaba.druid.pool.DruidDataSource # 当前数据源操作类型 driver-class-name: com.mysql.cj.jdbc.Driver # mysql驱动包 url: jdbc:mysql://localhost:3306/mydb111?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=GMT%2B8 username: root password: 123456 mybatis: mapperLocations: classpath:mapper/*.xml type-aliases-package: com.atguigu.springcloud.entities # 所有Entity别名类所在包 eureka: client: register-with-eureka: true #表示将自己注册进Eureka Server fetch-registry: true #表示是否从EurekaServer抓取已有的注册信息,默认为true。单节点无所谓,集群必须设置为true才能配合ribbon使用负载均衡 service-url: defaultZone: http://eureka7001.com:7001/eureka,http://eureka7002.com:7002/eureka
主启动:
package com.atguigu.springcloud;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
@SpringBootApplication
@EnableEurekaClient
public class PaymentMain8002 {
public static void main(String[] args) {
SpringApplication.run(PaymentMain8002.class,args);
}
}
修改8001的controller层:
package com.atguigu.springcloud.controller; import com.atguigu.springcloud.entities.CommonResult; import com.atguigu.springcloud.entities.Payment; import com.atguigu.springcloud.service.PaymentService; import lombok.extern.slf4j.Slf4j; import org.springframework.beans.factory.annotation.Value; import org.springframework.web.bind.annotation.*; import javax.annotation.Resource; /** */ @RestController @Slf4j public class PaymentController{ @Resource private PaymentService paymentService; @Value("${server.port}") private String serverPort; @PostMapping(value = "/payment/create") public CommonResult create(@RequestBody Payment payment) {//此处一定要加@RequestBody,否则80调用8001时,无法传递数据 log.info("前端传递数据:"+payment); int result = paymentService.create(payment); log.info("************************插入结果:" +result); if (result > 0) { return new CommonResult(200,"插入数据库成功,serverPort为: "+serverPort,result); } else { return new CommonResult(444,"插入数据库失败,serverPort为: "+serverPort, null); } } @GetMapping(value = "/payment/get/{id}") public CommonResult<Payment> getPaymentById(@PathVariable("id") Long id) { Payment payment = paymentService.getPaymentById(id); log.info("*************************查询结果:" +payment); if (payment != null) { return new CommonResult(200, "查询成功,serverPort为: "+serverPort, payment); } else { return new CommonResult(445,"没有对应id: "+id+" 的记录,serverPort为: "+serverPort, null); } } }
8002的controller类似:
package com.atguigu.springcloud.controller; import com.atguigu.springcloud.entities.CommonResult; import com.atguigu.springcloud.entities.Payment; import com.atguigu.springcloud.service.PaymentService; import lombok.extern.slf4j.Slf4j; import org.springframework.beans.factory.annotation.Value; import org.springframework.web.bind.annotation.*; import javax.annotation.Resource; /** */ @RestController @Slf4j public class PaymentController{ @Resource private PaymentService paymentService; @Value("${server.port}") private String serverPort; @PostMapping(value = "/payment/create") public CommonResult create(@RequestBody Payment payment) {//此处一定要加@RequestBody,否则80调用8001时,无法传递数据 log.info("前端传递数据:"+payment); int result = paymentService.create(payment); log.info("************************插入结果:" +result); if (result > 0) { return new CommonResult(200,"插入数据库成功,serverPort为: "+serverPort,result); } else { return new CommonResult(444,"插入数据库失败,serverPort为: "+serverPort, null); } } @GetMapping(value = "/payment/get/{id}") public CommonResult<Payment> getPaymentById(@PathVariable("id") Long id) { Payment payment = paymentService.getPaymentById(id); log.info("*************************查询结果:" +payment); if (payment != null) { return new CommonResult(200, "查询成功,serverPort为: "+serverPort, payment); } else { return new CommonResult(445,"没有对应id: "+id+" 的记录,serverPort为: "+serverPort, null); } } }
测试:
启动7001、7002再启动8001、8002、80项目查看效果,访问localhost:8001/payment/get/1进行自测,成功界面如下:
http://localhost:8001/payment/get/1
http://localhost:8002/payment/get/1
http://eureka7001.com:7001/
http://eureka7002.com:7002/
http://localhost/consumer/payment/get/1
出现的问题:
我们访问http://localhost/consumer/payment/get/1
,一直访问都是使用的端口为8001的生产者服务。不会调用到端口为8002的生产者服务。
原因是在消费者服务的controller层中,我们将请求路径写死了,如下图:
我们只需要换成生产者的服务名称就行了,如下图:
package com.atguigu.springcloud.controller; import com.atguigu.springcloud.entities.CommonResult; import com.atguigu.springcloud.entities.Payment; import lombok.extern.slf4j.Slf4j; 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 javax.annotation.Resource; @RestController @Slf4j public class OrderController { @Resource private RestTemplate restTemplate; public static final String PAYMENT_URL = "http://CLOUD-PAYMENT-SERVICE"; @GetMapping("/consumer/payment/create") public CommonResult<Payment> create(Payment payment){ return restTemplate.postForObject(PAYMENT_URL+"/payment/create", payment, CommonResult.class); } @GetMapping("/consumer/payment/get/{id}") public CommonResult<Payment> getPayment(@PathVariable("id") Long id){ return restTemplate.getForObject(PAYMENT_URL+"/payment/get/"+id, CommonResult.class); } }
但是访问localhost/consumer/payment/get/1会出现如下报错信息:
原因是我们配置了以服务名的方式访问,但不能确定是哪一个服务。
所以我们需要给restTemplate
开启负载均衡,默认是轮循。
只需要在restTemplate
配置类中加上@LoadBalanced
这个注解,该注解就是开启负载均衡的。
如下图:
package com.atguigu.springcloud.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 ApplicationContextConfig { @Bean //RestTemplate 的负载均衡能力 @LoadBalanced public RestTemplate getRestTemplate(){ return new RestTemplate(); } }
然后我们重启消费者服务,再次访问localhost/consumer/payment/get/1
,已经开启了负载均衡,生产者的两个服务交替轮循,如下图:
我们看一下@LoadBalanced注解的源码,如下图:
/**
* Annotation to mark a RestTemplate bean to be configured to use a LoadBalancerClient
* @author Spencer Gibb
*/
@Target({ ElementType.FIELD, ElementType.PARAMETER, ElementType.METHOD })
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
@Qualifier
public @interface LoadBalanced {
}
可以看到 @LoadBalanced是一个注解,用于标记要配置为使用LoadBalancerClient的RestTemplate bean的。那么我们再来看看 LoadBalancerClient,如下图:
public interface ServiceInstanceChooser {
ServiceInstance choose(String serviceId);
}
public interface LoadBalancerClient extends ServiceInstanceChooser {
<T> T execute(String serviceId, LoadBalancerRequest<T> request) throws IOException;
<T> T execute(String serviceId, ServiceInstance serviceInstance, LoadBalancerRequest<T> request) throws IOException;
URI reconstructURI(ServiceInstance instance, URI original);
}
1、LoadBalancerClient
是一个接口,该接口中有四个方法,我们来大概看一下这几个方法的作用:
ServiceInstance choose(String serviceId)
根据传入的服务名serviceId
从客户端负载均衡器中挑选一个对应服务的实例。
2、T execute()
,使用从负载均衡器中挑选出来的服务实例来执行请求。
3、URI reconstructURI(ServiceInstance instance, URI original)
表示为系统构建一个合适的URI,我们在Spring Cloud
中服务的发现与消费一文中发送请求时使用了服务的逻辑名称(http://HELLO-SERVICE/hello)
而不是具体的服务地址,在reconstructURI
方法中,第一个参数ServiceInstance
实例是一个带有host
和port
的具体服务实例,第二个参数URI
则是使用逻辑服务名定义为host
和port
的URI
,而返回的URI
则是通过ServiceInstance
的服务实例详情拼接出的具体的host:port
形式的请求地址。一言以蔽之,就是把类似于http://HELLO-SERVICE/hello
这种地址转为类似于http://195.124.207.128/hello
地址(IP地址也可能是域名)。
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