Spring Cloud 使用 Kubernetes 作为注册中心

Dear 丶 2024-04-18 15:12 80阅读 0赞

# Spring Cloud 使用 Kubernetes 作为注册中心 #

> Spring Cloud 可以使用 Kubernetes 作为注册中心，实现服务注册和发现

创建两个应用，Consumer 和 Provider，Provider 提供一个 REST 接口供 Consumer 调用

## Provider ##

### 添加依赖 ###

*  build.gradle

### 添加配置 ###

*  application.properties

指定服务的名称，用于实现调用

spring.application.name=provider-service
    server.port=8082

*  ProviderApplication.java

添加 `@EnableDiscoveryClient`启用服务发现

@SpringBootApplication
    @EnableDiscoveryClient
    public class ProviderApplication { 
    
        public static void main(String[] args) { 
            SpringApplication.run(ProviderApplication.class, args);
        }
    }

### 添加接口 ###

@GetMapping("/ping")
        @ResponseBody
        public String ping() { 
            try { 
                return InetAddress.getLocalHost().getHostName();
            } catch (UnknownHostException e) { 
                return "Pong";
            }
        }

### 部署到 Kubernetes ###

*  Dockerfile

FROM openjdk:8-jdk-alpine
    VOLUME /tmp
    ENV TZ=Asia/Shanghai
    RUN ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone
    ARG JAR_FILE
    ADD discovery/provider/build/libs/provider-0.0.1-SNAPSHOT.jar app.jar
    ENTRYPOINT ["java","-Djava.security.egd=file:/dev/./urandom", "-Duser.timezone=GMT+08", "-jar","/app.jar"]

构建并上传镜像

*  provider-service.yaml

apiVersion: v1
    kind: Service
    metadata:
      name: provider-service
      labels:
        app.kubernetes.io/name: provider-service
    spec:
      type: ClusterIP
      ports:
        - port: 8082
          targetPort: 8082
          protocol: TCP
          name: http
      selector:
        app.kubernetes.io/name: provider-service
    
    ---
    apiVersion: apps/v1
    kind: Deployment
    metadata:
      name: provider-service
      labels:
        app.kubernetes.io/name: provider-service
    spec:
      replicas: 1
      selector:
        matchLabels:
          app.kubernetes.io/name: provider-service
      template:
        metadata:
          labels:
            app.kubernetes.io/name: provider-service
            app.kubernetes.io/instance: sad-markhor
        spec:
          containers:
            - name: provider-service
              image: "docker.io/hellowoodes/spring-cloud-k8s-provider:1.2"
              imagePullPolicy: IfNotPresent
              ports:
                - name: http
                  containerPort: 8082
                  protocol: TCP

## Consumer ##

### 添加依赖 ###

*  build.gradle

dependencies {
        compile project(":discovery/common")
    
        implementation 'org.springframework.boot:spring-boot-starter-actuator'
        implementation 'org.springframework.boot:spring-boot-starter-web'
    
        implementation 'org.springframework.cloud:spring-cloud-starter-kubernetes-all'
        implementation 'org.springframework.cloud:spring-cloud-starter-openfeign'
        implementation 'org.springframework.cloud:spring-cloud-starter-netflix-ribbon'
        implementation 'io.github.openfeign:feign-java8'
    
        compileOnly 'org.projectlombok:lombok'
        annotationProcessor 'org.projectlombok:lombok'
    
        testImplementation 'org.springframework.boot:spring-boot-starter-test'
    }

不同的是 Consumer 还添加了 Feign 和 Ribbon 的依赖

### 添加配置 ###

*  application.properties

spring.application.name=consumer-service
    server.port=8081

*  ConsumerApplication.java

启用服务发现和 Feign 远程调用

@SpringBootApplication
    @EnableDiscoveryClient
    @EnableFeignClients
    public class ConsumerApplication { 
    
        public static void main(String[] args) { 
            SpringApplication.run(ConsumerApplication.class, args);
        }
    
    }

### 添加接口 ###

*  ConsumerController.java

@RestController
    @Slf4j
    public class ConsumerController { 
    
        @Autowired
        private DiscoveryClient discoveryClient;
    
        @Autowired
        private ProviderClient providerClient;
    
    
        @GetMapping("/service")
        public Object getClient() { 
            return discoveryClient.getServices();
        }
    
        @GetMapping("/instance")
        public List<ServiceInstance> getInstance(String instanceId) { 
            return discoveryClient.getInstances(instanceId);
        }
    
        @GetMapping("/ping")
        public OperationResponse ping() { 
            return OperationResponse
                    .builder()
                    .success(true)
                    .data(providerClient.ping())
                    .build();
        }
    }

*  ProviderClient.java

@FeignClient(name = "provider-service", fallback = ProviderClientFallback.class)
    public interface ProviderClient { 
    
        @RequestMapping(value = "/ping", method = RequestMethod.GET)
        String ping();
    }
    
    @Component
    class ProviderClientFallback implements ProviderClient { 
    
        @Override
        public String ping() { 
            return "Error";
        }
    }

### 部署到 Kubernetes ###

*  Dockerfile

FROM openjdk:8-jdk-alpine
    VOLUME /tmp
    ENV TZ=Asia/Shanghai
    RUN ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone
    ARG JAR_FILE
    ADD discovery/consumer/build/libs/consumer-0.0.1-SNAPSHOT.jar app.jar
    ENTRYPOINT ["java","-Djava.security.egd=file:/dev/./urandom", "-Duser.timezone=GMT+08", "-jar","/app.jar"]

构建并上传镜像

*  consumer-service.yaml

apiVersion: v1
    kind: Service
    metadata:
      name: consumer-service
      labels:
        app.kubernetes.io/name: consumer-service
    spec:
      type: NodePort
      ports:
        - port: 8081
          nodePort: 30081
          protocol: TCP
          name: http
      selector:
        app.kubernetes.io/name: consumer-service
    
    ---
    
    apiVersion: apps/v1
    kind: Deployment
    metadata:
      name: consumer-service
      labels:
        app.kubernetes.io/name: consumer-service
    spec:
      replicas: 1
      selector:
        matchLabels:
          app.kubernetes.io/name: consumer-service
      template:
        metadata:
          labels:
            app.kubernetes.io/name: consumer-service
        spec:
          containers:
            - name: consumer-service
              image: "docker.io/hellowoodes/spring-cloud-k8s-consumer:1.2"
              imagePullPolicy: IfNotPresent
              ports:
                - name: http
                  containerPort: 8081
                  protocol: TCP

## 部署测试 ##

### 部署 ###

kubectl apply -f discovery/provider/provider-service.yaml
    kubectl apply -f discovery/consumer/consumer-service.yaml

### 测试 ###

待部署完成后，访问 `${NODE_IP}:30081/${PATH}`即可得到服务信息

#### 测试接口 ####

*  ping

curl http://192.168.0.110:30081/ping
    { "success":true,"message":null,"data":"provider-service-bb8844f9b-c74rj"}%

*  service

curl http://192.168.0.110:30081/service
    ["backend","consumer-service","kubernetes","provider-service","traefik","traefik-dashboard"]%

*  instance

curl http://192.168.0.110:30081/instance\?instanceId\=provider-service
    
    [{ "instanceId":"87f35232-cb2a-4a35-a094-f4577bce195e","serviceId":"provider-service","secure":false,"metadata":{ "app.kubernetes.io/name":"provider-service","kubectl.kubernetes.io/last-applied-configuration":"{\"apiVersion\":\"v1\",\"kind\":\"Service\",\"metadata\":{\"annotations\":{},\"labels\":{\"app.kubernetes.io/name\":\"provider-service\"},\"name\":\"provider-service\",\"namespace\":\"default\"},\"spec\":{\"ports\":[{\"name\":\"http\",\"port\":8082,\"protocol\":\"TCP\",\"targetPort\":8082}],\"selector\":{\"app.kubernetes.io/name\":\"provider-service\"},\"type\":\"ClusterIP\"}}\n","port.http":"8082"},"uri":"http://10.32.0.8:8082","scheme":"http://","host":"10.32.0.8","port":8082}]%

#### 添加 Provider-Service 实例 ####

kubectl scale deploy/provider-service --replicas=3

待扩容完成后，多次访问 ping 接口，会看到在轮询访问每个 Provider 实例，每次返回的实例 ID 都不一样

curl http://192.168.0.110:30081/ping
    { "success":true,"message":null,"data":"provider-service-bb8844f9b-lm589"}%
    
    curl http://192.168.0.110:30081/ping
    { "success":true,"message":null,"data":"provider-service-bb8844f9b-n5szb"}%
    
    curl http://192.168.0.110:30081/ping
    { "success":true,"message":null,"data":"provider-service-bb8844f9b-c74rj"}%