Spring Cloud 快速上手之 Ribbon 负载均衡

架构探险之道

修改于 2020-05-18 18:16:57

7160

修改于 2020-05-18 18:16:57

Spring Cloud 快速上手之 Ribbon 负载均衡

简介

Spring Cloud Ribbon是基于HTTP和TCP的客户端负载工具，它是基于Netflix Ribbon实现的。通过Spring Cloud的封装，可以轻松地将面向服务的REST 模板请求，自动转换成客户端负载均衡服务调用。提供云端负载均衡，有多种负载均衡策略可供选择，可配合服务发现和断路器使用。

准备工作

开发环境

Greenwich.SR5
Spring Boot 2.1.5
MySQL 5.7
JDK 1.8

依赖管理

<!--负载均衡 Ribbon-->
<dependency>
  <groupId>org.springframework.cloud</groupId>
  <artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
</dependency>

需要注意的是，在spring-cloud-starter-netflix-eureka-client默认集成了spring-cloud-starter-netflix-ribbon，因此可以不引入。

Ribbon

基本配置

RestTemlate 配置

@Configuration
public class RpcConfig {

    @Bean
    //添加此注解后，可以直接通过 服务 ID 进行接口调用，而无需输入IP 和端口信息
    @LoadBalanced
    public RestTemplate restTemplate() {
        return new RestTemplate();
    }
}

RestController

@RestController
public class UserController {

    @Autowired
    private IUserService userService;

    @Autowired
    private LoadBalancerClient loadBalancerClient;

    @GetMapping("/user/{id}")
    public User findById(@PathVariable Long id) {
        return userService.findById(id);
    }

    @GetMapping("/instance/{instanceId}")
    public String instance(@PathVariable String instanceId) {
        ServiceInstance choose = loadBalancerClient.choose(instanceId);
        HashMap<String, String> instanceInfo = new HashMap<>();
        return JSON.toJSONString(choose,true);
    }
}

UserServiceImpl

@Service
public class UserServiceImpl implements IUserService {

    @Autowired
    private RestTemplate restTemplate;

    @Override
    public User findById(Long id) {
        return this.restTemplate.getForObject("http://ms-provider-user-v2/" + id, User.class);
    }

}

接口测试

http://localhost:8012/instance/ms-consumer-user-v2-ribbon

GET http://localhost:8012/instance/ms-consumer-user-v2-ribbon

HTTP/1.1 200 
Content-Type: application/json;charset=UTF-8
Content-Length: 1792
Date: Tue, 05 May 2020 06:10:12 GMT

{
  "host": "192.168.0.100",
  "instanceId": "192.168.0.100:8012",
  "metadata": {
    "management.port": "8012"
  },
  "port": 8012,
  "secure": false,
  "server": {
    "alive": true,
    "host": "192.168.0.100",
    "hostPort": "192.168.0.100:8012",
    "id": "192.168.0.100:8012",
    "instanceInfo": {
      "actionType": "ADDED",
      "appName": "MS-CONSUMER-USER-V2-RIBBON",
      "coordinatingDiscoveryServer": false,
      "countryId": 1,
      "dataCenterInfo": {
        "name": "MyOwn"
      },
      "dirty": false,
      "healthCheckUrl": "http://192.168.0.100:8012/actuator/health",
      "healthCheckUrls": [
        "http://192.168.0.100:8012/actuator/health"
      ],
      "homePageUrl": "http://192.168.0.100:8012/",
      "hostName": "192.168.0.100",
      "iPAddr": "192.168.0.100",
      "id": "192.168.0.100:ms-consumer-user-v2-ribbon:8012",
      "instanceId": "192.168.0.100:ms-consumer-user-v2-ribbon:8012",
      "lastDirtyTimestamp": 1588658754217,
      "lastUpdatedTimestamp": 1588658754758,
      "leaseInfo": {
        "durationInSecs": 90,
        "evictionTimestamp": 0,
        "registrationTimestamp": 1588658754758,
        "renewalIntervalInSecs": 30,
        "renewalTimestamp": 1588659024755,
        "serviceUpTimestamp": 1588658754254
      },
      "metadata": {
        "$ref": "$.metadata"
      },
      "overriddenStatus": "UNKNOWN",
      "port": 8012,
      "sID": "na",
      "securePort": 443,
      "secureVipAddress": "ms-consumer-user-v2-ribbon",
      "status": "UP",
      "statusPageUrl": "http://192.168.0.100:8012/actuator/info",
      "vIPAddress": "ms-consumer-user-v2-ribbon",
      "version": "unknown"
    },
    "metaInfo": {
      "appName": "MS-CONSUMER-USER-V2-RIBBON",
      "instanceId": "192.168.0.100:ms-consumer-user-v2-ribbon:8012",
      "serviceIdForDiscovery": "ms-consumer-user-v2-ribbon"
    },
    "port": 8012,
    "readyToServe": true,
    "zone": "defaultZone"
  },
  "serviceId": "ms-consumer-user-v2-ribbon",
  "uri": "http://192.168.0.100:8012"
}

Response code: 200; Time: 100ms; Content length: 1792 bytes

http://localhost:8012/user/16

GET http://localhost:8012/user/16

HTTP/1.1 200 
Content-Type: application/json;charset=UTF-8
Transfer-Encoding: chunked
Date: Tue, 05 May 2020 06:54:25 GMT

{
  "id": 16,
  "account": "account5",
  "userName": "x_user_5",
  "age": 20
}

Response code: 200; Time: 27ms; Content length: 61 bytes

负载均衡

配置服务提供者多实例

两个实例的启动参数分别为--spring.profiles.active=ribbon1和

--spring.profiles.active=ribbon2

server:
  port: 8011

spring:
  datasource:
    url: jdbc:mysql://127.0.0.1:3306/db_yier?characterEncoding=UTF-8&rewriteBatchedStatements=true
    username: root
    password: Abc123++
    driver-class-name: com.mysql.jdbc.Driver
  jpa:
    hibernate:
      ddl-auto: update
    show-sql: true
    database-platform: org.hibernate.dialect.MySQL5Dialect

  application:
    name: ms-provider-user-v2

eureka:
  client:
    service-url:
      defaultZone: http://localhost:8010/eureka/
  instance:
    prefer-ip-address: true

info:
  app:
    name: @project.artifactId@
    encoding: @project.build.sourceEncoding@
    java:
      source: @java.version@
      target: @java.version@


---
spring:
  profiles: ribbon1
server:
  port: 8013

---
spring:
  profiles: ribbon2
server:
  port: 8014

接口测试

http://localhost:8012/instance/ms-provider-user-v2

//第一次调用
GET http://localhost:8012/instance/ms-provider-user-v2

HTTP/1.1 200 
Content-Type: application/json;charset=UTF-8
Content-Length: 1729
Date: Tue, 05 May 2020 07:39:49 GMT

{
  "host": "192.168.0.100",
  "instanceId": "192.168.0.100:8014",
  "metadata": {
    "management.port": "8014"
  },
  "port": 8014,
  "secure": false,
  "server": {
    "alive": true,
    "host": "192.168.0.100",
    "hostPort": "192.168.0.100:8014",
    "id": "192.168.0.100:8014",
    "instanceInfo": {
      "actionType": "ADDED",
      "appName": "MS-PROVIDER-USER-V2",
      "coordinatingDiscoveryServer": false,
      "countryId": 1,
      "dataCenterInfo": {
        "name": "MyOwn"
      },
      "dirty": false,
      "healthCheckUrl": "http://192.168.0.100:8014/actuator/health",
      "healthCheckUrls": [
        "http://192.168.0.100:8014/actuator/health"
      ],
      "homePageUrl": "http://192.168.0.100:8014/",
      "hostName": "192.168.0.100",
      "iPAddr": "192.168.0.100",
      "id": "192.168.0.100:ms-provider-user-v2:8014",
      "instanceId": "192.168.0.100:ms-provider-user-v2:8014",
      "lastDirtyTimestamp": 1588663883990,
      "lastUpdatedTimestamp": 1588663884538,
      "leaseInfo": {
        "durationInSecs": 90,
        "evictionTimestamp": 0,
        "registrationTimestamp": 1588663884538,
        "renewalIntervalInSecs": 30,
        "renewalTimestamp": 1588664154534,
        "serviceUpTimestamp": 1588663884034
      },
      "metadata": {
        "$ref": "$.metadata"
      },
      "overriddenStatus": "UNKNOWN",
      "port": 8014,
      "sID": "na",
      "securePort": 443,
      "secureVipAddress": "ms-provider-user-v2",
      "status": "UP",
      "statusPageUrl": "http://192.168.0.100:8014/actuator/info",
      "vIPAddress": "ms-provider-user-v2",
      "version": "unknown"
    },
    "metaInfo": {
      "appName": "MS-PROVIDER-USER-V2",
      "instanceId": "192.168.0.100:ms-provider-user-v2:8014",
      "serviceIdForDiscovery": "ms-provider-user-v2"
    },
    "port": 8014,
    "readyToServe": true,
    "zone": "defaultZone"
  },
  "serviceId": "ms-provider-user-v2",
  "uri": "http://192.168.0.100:8014"
}

Response code: 200; Time: 12ms; Content length: 1729 bytes

//第二次调用

GET http://localhost:8012/instance/ms-provider-user-v2

HTTP/1.1 200 
Content-Type: application/json;charset=UTF-8
Content-Length: 1729
Date: Tue, 05 May 2020 07:40:26 GMT

{
  "host": "192.168.0.100",
  "instanceId": "192.168.0.100:8013",
  "metadata": {
    "management.port": "8013"
  },
  "port": 8013,
  "secure": false,
  "server": {
    "alive": true,
    "host": "192.168.0.100",
    "hostPort": "192.168.0.100:8013",
    "id": "192.168.0.100:8013",
    "instanceInfo": {
      "actionType": "ADDED",
      "appName": "MS-PROVIDER-USER-V2",
      "coordinatingDiscoveryServer": false,
      "countryId": 1,
      "dataCenterInfo": {
        "name": "MyOwn"
      },
      "dirty": false,
      "healthCheckUrl": "http://192.168.0.100:8013/actuator/health",
      "healthCheckUrls": [
        "http://192.168.0.100:8013/actuator/health"
      ],
      "homePageUrl": "http://192.168.0.100:8013/",
      "hostName": "192.168.0.100",
      "iPAddr": "192.168.0.100",
      "id": "192.168.0.100:ms-provider-user-v2:8013",
      "instanceId": "192.168.0.100:ms-provider-user-v2:8013",
      "lastDirtyTimestamp": 1588663874416,
      "lastUpdatedTimestamp": 1588663874966,
      "leaseInfo": {
        "durationInSecs": 90,
        "evictionTimestamp": 0,
        "registrationTimestamp": 1588663874966,
        "renewalIntervalInSecs": 30,
        "renewalTimestamp": 1588664144962,
        "serviceUpTimestamp": 1588663874460
      },
      "metadata": {
        "$ref": "$.metadata"
      },
      "overriddenStatus": "UNKNOWN",
      "port": 8013,
      "sID": "na",
      "securePort": 443,
      "secureVipAddress": "ms-provider-user-v2",
      "status": "UP",
      "statusPageUrl": "http://192.168.0.100:8013/actuator/info",
      "vIPAddress": "ms-provider-user-v2",
      "version": "unknown"
    },
    "metaInfo": {
      "appName": "MS-PROVIDER-USER-V2",
      "instanceId": "192.168.0.100:ms-provider-user-v2:8013",
      "serviceIdForDiscovery": "ms-provider-user-v2"
    },
    "port": 8013,
    "readyToServe": true,
    "zone": "defaultZone"
  },
  "serviceId": "ms-provider-user-v2",
  "uri": "http://192.168.0.100:8013"
}

Response code: 200; Time: 12ms; Content length: 1729 bytes

关注"instanceId": "192.168.0.100:ms-provider-user-v2:8013",

和 "instanceId": "192.168.0.100:ms-provider-user-v2:8014",

可以发现实现了负载均衡，两次请求被均匀的分配到2个ms-provider-user-v2服务实例上。

源码分析

LoadBalancerInterceptor

LoadBalancerInterceptor是注解@LoadBalanced的关联实现类。

/**
 * @author Spencer Gibb
 * @author Dave Syer
 * @author Ryan Baxter
 * @author William Tran
 */
public class LoadBalancerInterceptor implements ClientHttpRequestInterceptor {

    private LoadBalancerClient loadBalancer;

    private LoadBalancerRequestFactory requestFactory;

    public LoadBalancerInterceptor(LoadBalancerClient loadBalancer,
            LoadBalancerRequestFactory requestFactory) {
        this.loadBalancer = loadBalancer;
        this.requestFactory = requestFactory;
    }

    public LoadBalancerInterceptor(LoadBalancerClient loadBalancer) {
        // for backwards compatibility
        this(loadBalancer, new LoadBalancerRequestFactory(loadBalancer));
    }

    @Override
    public ClientHttpResponse intercept(final HttpRequest request, final byte[] body,
            final ClientHttpRequestExecution execution) throws IOException {
        final URI originalUri = request.getURI();
        String serviceName = originalUri.getHost();
        Assert.state(serviceName != null,
                "Request URI does not contain a valid hostname: " + originalUri);
        return this.loadBalancer.execute(serviceName,
                this.requestFactory.createRequest(request, body, execution));
    }

}

在LoadBalancerAutoConfiguration中，会对RestTemplate进行增强处理：

//传入拦截器
@Bean
@ConditionalOnMissingBean
public RestTemplateCustomizer restTemplateCustomizer(
  final LoadBalancerInterceptor loadBalancerInterceptor) {
  return restTemplate -> {
    List<ClientHttpRequestInterceptor> list = new ArrayList<>(
      restTemplate.getInterceptors());
    list.add(loadBalancerInterceptor);
    restTemplate.setInterceptors(list);
  };
}

//加工RestTemplate
@Bean
public SmartInitializingSingleton loadBalancedRestTemplateInitializerDeprecated(
  final ObjectProvider<List<RestTemplateCustomizer>> restTemplateCustomizers) {
  return () -> restTemplateCustomizers.ifAvailable(customizers -> {
    for (RestTemplate restTemplate : LoadBalancerAutoConfiguration.this.restTemplates) {
      for (RestTemplateCustomizer customizer : customizers) {
        customizer.customize(restTemplate);
      }
    }
  });
}

而在 Spring 容器注入单例 Bean 的时候，会在DefaultListableBeanFactory中调用如下一段代码：

// Trigger post-initialization callback for all applicable beans...
        for (String beanName : beanNames) {
            Object singletonInstance = getSingleton(beanName);
            if (singletonInstance instanceof SmartInitializingSingleton) {
                final SmartInitializingSingleton smartSingleton = (SmartInitializingSingleton) singletonInstance;
                if (System.getSecurityManager() != null) {
                    AccessController.doPrivileged((PrivilegedAction<Object>) () -> {
                        smartSingleton.afterSingletonsInstantiated();
                        return null;
                    }, getAccessControlContext());
                }
                else {
                    smartSingleton.afterSingletonsInstantiated();
                }
            }
        }

负载均衡策略

改变负载均衡策略，配置形式，或者注解形式都可以（IRule）

配置文件

ms-provider-user-v2:
  ribbon:
    # 配置随机策略
    NFLoadBalancerRuleClassName: com.netflix.loadbalancer.RandomRule

代码配置

/**
  * 配置均衡负载策略
  * @return
  */
@Bean
public IRule ribbonRule() {
  return new RandomRule();
}

# 测试 LoadBalancerClient 返回的 实例 ms-provider-user-v2 的信息
GET http://localhost:8012/instance/ms-provider-user-v2
Accept: application/json

通过返回的结果测试，可以验证是随机的，而非默认的轮询选择机制。

单独使用

依赖配置

删除spring-cloud-starter-netflix-eureka-client，并引入配置：

<!--负载均衡 Ribbon-->
<dependency>
  <groupId>org.springframework.cloud</groupId>
  <artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
</dependency>

配置

server:
  port: 8012

spring:
  application:
    name: ms-consumer-user-v2-ribbon-single

#ms-provider-user-v2:
#  ribbon:
#    # 配置随机策略
#    NFLoadBalancerRuleClassName: com.netflix.loadbalancer.RandomRule

# 单独使用，不使用 Eureka
ms-provider-user-v2:
  ribbon:
    listOfServers: localhost:8013,localhost:8014

测试

GET http://localhost:8012/instance/ms-provider-user-v2

HTTP/1.1 200 
Content-Type: application/json;charset=UTF-8
Content-Length: 390
Date: Tue, 05 May 2020 08:27:49 GMT

{
  "host": "localhost",
  "instanceId": "localhost:8013",
  "metadata": {},
  "port": 8013,
  "secure": false,
  "server": {
    "alive": true,
    "host": "localhost",
    "hostPort": "localhost:8013",
    "id": "localhost:8013",
    "metaInfo": {
      "instanceId": "localhost:8013"
    },
    "port": 8013,
    "readyToServe": true,
    "zone": "UNKNOWN"
  },
  "serviceId": "ms-provider-user-v2",
  "uri": "http://localhost:8013"
}

Response code: 200; Time: 507ms; Content length: 390 bytes

结果轮询返回的端口为 8013 或 8014。

饥饿加载

默认情况下Ribbon是懒加载的。当服务起动好之后，第一次请求是非常慢的，第二次之后就快很多。其解决方式：开启饥饿加载。

ribbon:
 eager-load:
  # 开启饥饿加载
  enabled: true 
  # 为哪些服务的名称开启饥饿加载,多个用逗号分隔
  clients: server-1,server-2,server-3

Spring Cloud 会为每个名称的 Ribbon Client 维护一个子应用程序的上下文，默认是懒加载的，配置饥饿加载后，可以在启动时就加载对应子应用程序的上下文，从而提高首次请求的访问速度

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原始发表：2020-05-06，如有侵权请联系 cloudcommunity@tencent.com 删除

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Spring Cloud 快速上手之 Ribbon 负载均衡

Spring Cloud 快速上手之 Ribbon 负载均衡

Spring Cloud 快速上手之 Ribbon 负载均衡

Ribbon

基本配置

负载均衡

源码分析

负载均衡策略

单独使用

饥饿加载

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