K8S - 理解ClusterIP - 集群内部service之间的反向代理和loadbalancer

集群内部通信：ClusterIP 为 Service 提供了一个虚拟的内部 IP 地址，用于在 Kubernetes 集群内的其他组件和服务之间进行通信。其他 Pod 可以通过该虚拟 IP 地址和 Service 的端口来访问该 Service。内部负载均衡：ClusterIP 实现了基于轮询算法的负载均衡，它将请求均匀地分发给 Service 关联的后端 Pod。这意味着无论有多少个后端 Pod

nvd11

1924人浏览 · 2024-06-23 21:07:00

nvd11 · 2024-06-23 21:07:00 发布

在Micro Service的治理中。

有两个很重要的点，

集群外部的用户/service 如何访问集群内的入口服务(例如UI service）
集群内的service A 如何访问集群内的service B

为什么有上面的问题
无非是：

集群内的service 都是多实例的
每个service 实例都有单独不同的ip
如何负载均衡？

如图：
在这里插入图片描述

Spring Cloud 是如何就解决这两个问题的

集群外 to 集群内

用spring cloud gateway 来反向代理集群内的对外service, 例如图中的Service A, 如果其他Service 没有被配置在gateway中，集群外部是无法直接访问的，更加安全。通常这个api gateway所在的server 具有双网卡， 1个ip在外网， 1个ip在集群内网
同是Spring Cloud Gateway 自带Load balancer 功能(基于 Spring cloud loadbalancer) , 所以即使要exposed 的service 有多个实例， Gateway同样可以根据指定规则分发到不同的instance.

集群内 Service A to Service B

使用Eureke 作为注册中心，每个service 的instance 都要往里面注册，以给每个service 的多个instance 获得1个common的service Name作为DNS
使用Ribbon(继承在Eureka) 中，作为load balancer 进行request转发

如图：
在这里插入图片描述

k8s 是如何就解决这两个问题的

K8S 的service 包括了很多种，
ingress, nodeport, clusterIp, externalName 都是属于service的

集群外 to 集群内

使用ingress or NodePort 来作为纵向流量代理，而ingress 和 NodePort 都是自带load balancer 的。
置于什么是纵向横向流量
参考
使用ClusterIP 作为 Service B之的反向代理， ClusterIP 的service自带loadbalancer 功能，这样Service A就可以通过ClusterIP service的名字DNS 来访问Service B了
虽然k8s 没用Eureka, Nacos等注册中心，但是实际上k8s 的service list 实际上就是1个注册中心了！

原理如图：
在这里插入图片描述

ClusterIP 的定义和简单介绍

集群内部通信：ClusterIP 为 Service 提供了一个虚拟的内部 IP 地址，用于在 Kubernetes 集群内的其他组件和服务之间进行通信。其他 Pod 可以通过该虚拟 IP 地址和 Service 的端口来访问该 Service。
内部负载均衡：ClusterIP 实现了基于轮询算法的负载均衡，它将请求均匀地分发给 Service 关联的后端 Pod。这意味着无论有多少个后端 Pod，它们都可以被平等地访问，从而实现负载均衡和高可用性。
集群外部不可访问：ClusterIP 分配的 IP 地址只在 Kubernetes 集群内部可见，对集群外部不可访问。它不直接暴露给外部网络，因此不能直接从集群外部访问该 IP 地址。
适用于内部服务：ClusterIP 适用于内部服务，即那些只需要在 Kubernetes 集群内部可访问的服务。这些服务通常用于应用程序的内部组件之间的通信，例如数据库连接、队列服务等。
可用于其他类型的 Service：ClusterIP 可以作为其他类型的 Service（如 NodePort、LoadBalancer 或 Ingress）的后端服务。通过将其他类型的 Service 配置为使用 ClusterIP 类型的 Service，可以将请求转发到 ClusterIP 提供的虚拟 IP 地址上。

总的来说，ClusterIP 是 Kubernetes 集群内部的一种服务发现和负载均衡机制，用于实现集群内部的内部通信和服务访问。它提供了一个虚拟 IP 地址给 Service，并通过负载均衡算法将请求分发给关联的后端 Pod。ClusterIP 适用于内部服务，不直接对外部公开。

NodePort 和 ClusterIP 的具体例子

解下来我会用 NodePort 和 ClusterIP 来demo 以下 k8s service A 如何访问 ServiceB
置于从集群外访问为何不用ingress, 是因为k8s 的博文系列还没提到Ingress.

大概框架
在这里插入图片描述

在这个例子中
我们会部署：
Service A: bq-api-service
Service B: cloud-user
nodePort service: nodeport-bq-api-service
clusterIP service: clusterip-cloud-user

置于这里两个service 具体是什么不重要，可以认为它们是两个简单的springboot service 并没有集成任何spring cloud 的框架。

cleanup

当前k8s 环境是干净的

[gateman@manjaro-x13 bq-api-service]$ kubectl get all -o wide
NAME                 TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE   SELECTOR
service/kubernetes   ClusterIP   10.96.0.1    <none>        443/TCP   77d   <none>

部署 Service B ， cloud-user service

更新info 接口让其return hostname

先update /actuator/info 接口让其可以return 当前service 所在server/container 的hostname

@Component
@Slf4j
public class AppVersionInfo implements InfoContributor {

    @Value("${pom.version}") // https://stackoverflow.com/questions/3697449/retrieve-version-from-maven-pom-xml-in-code
    private String appVersion;

    @Autowired
    private String hostname;

    @Value("${spring.datasource.url}")
    private String dbUrl;

    @Override
    public void contribute(Info.Builder builder) {
        log.info("AppVersionInfo: contribute ...");
        builder.withDetail("app", "Cloud User API")
                .withDetail("version", appVersion)
                .withDetail("hostname",hostname)
                .withDetail("dbUrl", dbUrl)
                .withDetail("description", "This is a simple Spring Boot application to demonstrate the use of BigQuery in GCP.");
    }
}

测试效果：

[gateman@manjaro-x13 bq-api-service]$ curl 127.0.0.1:8080/actuator/info
{"app":"Cloud User API","version":"0.0.1","hostname":"manjaro-x13","dbUrl":"jdbc:mysql://34.39.2.90:6033/demo_cloud_user?useUnicode=true&characterEncoding=utf-8&useSSL=false&allowPublicKeyRetrieval=true","description":"This is a simple Spring Boot application to demonstrate the use of BigQuery in GCP."}
[gateman@manjaro-x13 bq-api-service]$

利用cloudbuild 和其trigger 让其自动部署docker image 到GAR (google artifact repository)

cloudbuild-gar.yaml

# just to update the docker image to GAR with the pom.xml version

steps:
  - id: run maven install
    name: maven:3.9.6-sapmachine-17 # https://hub.docker.com/_/maven
    entrypoint: bash
    args:
      - '-c'
      - |
        whoami
        set -x
        pwd
        mvn install
        cat pom.xml | grep -m 1 "<version>" | sed -e 's/.*<version>\([^<]*\)<\/version>.*/\1/' > /workspace/version.txt
        echo "Version: $(cat /workspace/version.txt)"


  - id: build and push docker image
    name: 'gcr.io/cloud-builders/docker'
    entrypoint: bash
    args:
      - '-c'
      - |
        set -x
        echo "Building docker image with tag: $(cat /workspace/version.txt)"
        docker build -t $_GAR_BASE/$PROJECT_ID/$_DOCKER_REPO_NAME/${_APP_NAME}:$(cat /workspace/version.txt) .
        docker push $_GAR_BASE/$PROJECT_ID/$_DOCKER_REPO_NAME/${_APP_NAME}:$(cat /workspace/version.txt)


logsBucket: gs://jason-hsbc_cloudbuild/logs/
options: # https://cloud.google.com/cloud-build/docs/build-config#options
  logging: GCS_ONLY # or CLOUD_LOGGING_ONLY https://cloud.google.com/cloud-build/docs/build-config#logging

substitutions:
  _DOCKER_REPO_NAME: my-docker-repo
  _APP_NAME: cloud-user
  _GAR_BASE: europe-west2-docker.pkg.dev

cloudbuild trigger:
terraform：

# referring https://registry.terraform.io/providers/hashicorp/google/latest/docs/resources/cloudbuild_trigger
resource "google_cloudbuild_trigger" "cloud-user-gar-trigger" {
  name = "cloud-user-gar-trigger" # could not contains underscore

  location = var.region_id

  # when use github then should use trigger_template
  github {
    name = "demo_cloud_user"
    owner = "nvd11"
    push {
      branch = "main"
      invert_regex = false # means trigger on branch
    }
  }


  filename = "cloudbuild-gar.yaml"
  # projects/jason-hsbc/serviceAccounts/terraform@jason-hsbc.iam.gserviceaccount.com
  service_account = data.google_service_account.cloudbuild_sa.id 
}

这样，一但有任何commit 推送到github main branch
cloudbuild 就会自动打包docker image 到指定的 GAR 仓库
url：
europe-west2-docker.pkg.dev/jason-hsbc/my-docker-repo/cloud-user:xxx

其中xxx 是pom.xml 里定义的version 数字

有了这个image path,就方便了后面在k8s 部署

编写yaml 脚本

deployment-cloud-user.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  labels: # label of this deployment
    app: cloud-user # custom defined
    author: nvd11
  name: deployment-cloud-user # name of this deployment
  namespace: default
spec:
  replicas: 4            # desired replica count, Please note that the replica Pods in a Deployment are typically distributed across multiple nodes.
  revisionHistoryLimit: 10 # The number of old ReplicaSets to retain to allow rollback
  selector: # label of the Pod that the Deployment is managing,, it's mandatory, without it , we will get this error 
            # error: error validating data: ValidationError(Deployment.spec.selector): missing required field "matchLabels" in io.k8s.apimachinery.pkg.apis.meta.v1.LabelSelector ..
    matchLabels:
      app: cloud-user
  strategy: # Strategy of upodate
    type: RollingUpdate # RollingUpdate or Recreate
    rollingUpdate:
      maxSurge: 25% # The maximum number of Pods that can be created over the desired number of Pods during the update
      maxUnavailable: 25% # The maximum number of Pods that can be unavailable during the update
  template: # Pod template
    metadata:
      labels:
        app: cloud-user # label of the Pod that the Deployment is managing. must match the selector, otherwise, will get the error Invalid value: map[string]string{"app":"bq-api-xxx"}: `selector` does not match template `labels`
    spec:
      containers:
      - image: europe-west2-docker.pkg.dev/jason-hsbc/my-docker-repo/cloud-user:1.0.1 # image of the container
        imagePullPolicy: IfNotPresent
        name: container-cloud-user
        env: # set env varaibles
        - name: APP_ENVIRONMENT
          value: prod
      restartPolicy: Always # Restart policy for all containers within the Pod
      terminationGracePeriodSeconds: 10 # The period of time in seconds given to the Pod to terminate gracefully

部署yaml

[gateman@manjaro-x13 cloud-user]$ kubectl apply -f deployment-cloud-user.yaml 
deployment.apps/deployment-cloud-user created
[gateman@manjaro-x13 cloud-user]$ kubectl get pods -o wide
NAME                                     READY   STATUS    RESTARTS   AGE    IP             NODE        NOMINATED NODE   READINESS GATES
deployment-cloud-user-65fb8d79fd-28vmn   1/1     Running   0          104s   10.244.2.133   k8s-node0   <none>           <none>
deployment-cloud-user-65fb8d79fd-9rjln   1/1     Running   0          104s   10.244.2.134   k8s-node0   <none>           <none>
deployment-cloud-user-65fb8d79fd-m8xv4   1/1     Running   0          104s   10.244.1.67    k8s-node1   <none>           <none>
deployment-cloud-user-65fb8d79fd-ndvjb   1/1     Running   0          104s   10.244.3.76    k8s-node3   <none>           <none>

可以见到 4个pods 跑起来了

初步测试

cloud-user 是部署好了，但是它没有配置nodeport 和 clusterIP 等任何service, 所以它是无法被nodes 的service 访问的。

上面的pods信息里显示了 ip address, 但那些ip address 是容器level, 只能被另1个容器访问。

这样的话，我们可以进入1个新建的容器内测试:

新建dns-test 测试pod

[gateman@manjaro-x13 cloud-user]$ kubectl run dns-test --image=odise/busybox-curl --restart=Never -- /bin/sh -c "while true; do echo hello docker; sleep 1; done"
pod/dns-test created

这样dns-test pod 就创建成功了，之所以要加上一段 while死循环是避免这个pod 自动complete退出

进入测试容器

[gateman@manjaro-x13 cloud-user]$ kubectl get pods -o wide
NAME                                     READY   STATUS    RESTARTS   AGE   IP             NODE        NOMINATED NODE   READINESS GATES
deployment-cloud-user-65fb8d79fd-28vmn   1/1     Running   0          15m   10.244.2.133   k8s-node0   <none>           <none>
deployment-cloud-user-65fb8d79fd-9rjln   1/1     Running   0          15m   10.244.2.134   k8s-node0   <none>           <none>
deployment-cloud-user-65fb8d79fd-m8xv4   1/1     Running   0          15m   10.244.1.67    k8s-node1   <none>           <none>
deployment-cloud-user-65fb8d79fd-ndvjb   1/1     Running   0          15m   10.244.3.76    k8s-node3   <none>           <none>
dns-test                                 1/1     Running   0          6s    10.244.2.135   k8s-node0   <none>           <none>

[gateman@manjaro-x13 cloud-user]$ kubectl exec -it dns-test -- /bin/sh
/ #

十分简单

在容器内调用各个pod的api

/ # curl 10.244.2.133:8080/actuator/info
{"app":"Cloud User API","version":"1.0.1","hostname":"deployment-cloud-user-65fb8d79fd-28vmn","dbUrl":"jdbc:mysql://192.168.0.42:3306/demo_cloud_user?useUnicode=true&characterEncoding=utf-8&useSSL=false&allowPublicKeyRetrieval=true","description":"This is a simple Spring Boot application to demonstrate the use of BigQuery in GCP."}/ # 
/ # 
/ # curl 10.244.2.134:8080/actuator/info
{"app":"Cloud User API","version":"1.0.1","hostname":"deployment-cloud-user-65fb8d79fd-9rjln","dbUrl":"jdbc:mysql://192.168.0.42:3306/demo_cloud_user?useUnicode=true&characterEncoding=utf-8&useSSL=false&allowPublicKeyRetrieval=true","description":"This is a simple Spring Boot application to demonstrate the use of BigQuery in GCP."}/ # 
/ # 
/ # 
/ # curl 10.244.1.67:8080/actuator/info
{"app":"Cloud User API","version":"1.0.1","hostname":"deployment-cloud-user-65fb8d79fd-m8xv4","dbUrl":"jdbc:mysql://192.168.0.42:3306/demo_cloud_user?useUnicode=true&characterEncoding=utf-8&useSSL=false&allowPublicKeyRetrieval=true","description":"This is a simple Spring Boot application to demonstrate the use of BigQuery in GCP."}/ # 
/ # 
/ # curl 10.244.3.76:8080/actuator/info
{"app":"Cloud User API","version":"1.0.1","hostname":"deployment-cloud-user-65fb8d79fd-ndvjb","dbUrl":"jdbc:mysql://192.168.0.42:3306/demo_cloud_user?useUnicode=true&characterEncoding=utf-8&useSSL=false&allowPublicKeyRetrieval=true","description":"This is a simple Spring Boot application to demonstrate the use of BigQuery in GCP."}/ # 
/ # 
/ #

可以见到4个pod的 service 都可以被dns-test 容器内call 通，能分别return 它们的hostname, 但是调用时要指定ip ，无法做到统一入口和 load balance

部署 ClusterIP - clusterip-cloud-user

编写yaml

clusterip-cloud-user.yaml

apiVersion: v1
kind: Service
metadata:
  name: clusterip-cloud-user
spec:
  selector:
    app: cloud-user # for the pods that have the label app: cloud-user
  ports:
    - protocol: TCP
      port: 8080
      targetPort: 8080
  type: ClusterIP

由于加上了selector ，所以endpoint 也会自动创建

部署yaml

[gateman@manjaro-x13 cloud-user]$ kubectl create -f clusterip-cloud-user.yaml 
service/clusterip-cloud-user created

检查一下：

[gateman@manjaro-x13 cloud-user]$ kubectl get svc -o wide
NAME                   TYPE        CLUSTER-IP    EXTERNAL-IP   PORT(S)    AGE   SELECTOR
clusterip-cloud-user   ClusterIP   10.96.11.18   <none>        8080/TCP   29s   app=cloud-user
kubernetes             ClusterIP   10.96.0.1     <none>        443/TCP    77d   <none>
[gateman@manjaro-x13 cloud-user]$ kubectl get ep -o wide
NAME                   ENDPOINTS                                                          AGE
clusterip-cloud-user   10.244.1.67:8080,10.244.2.133:8080,10.244.2.134:8080 + 1 more...   2m36s
kubernetes             192.168.0.3:6443                                                   77d

可以见到1个cluster ip service 已被创建

名字是 clusterip-cloud-user, 类型是ClusterIP, Cluster-IP 就是所谓的虚拟ip

在endpoints 里面，可以见到这个clusterip service 代理的是 4个 ip和端口的组合，它们实际上就是 cloud-user 的4个pods

初步测试

ClusterIP 和 NodePort 不一样，是无法从容器外部直接访问的，
所以我们还是需要进入测试容器类测试

kubectl exec -it dns-test -- /bin/sh

之后我们可以用 $serviceName:$\port 去访问endpoints里的service了

/ # nslookup clusterip-cloud-user
Server:    10.96.0.10
Address 1: 10.96.0.10 kube-dns.kube-system.svc.cluster.local

Name:      clusterip-cloud-user
Address 1: 10.96.11.18 clusterip-cloud-user.default.svc.cluster.local

`
/ # ping clusterip-cloud-user

PING clusterip-cloud-user (10.96.11.18): 56 data bytes
^C
--- clusterip-cloud-user ping statistics ---
10 packets transmitted, 0 packets received, 100% packet loss
/ # curl clusterip-cloud-user:8080/actuator/info
{"app":"Cloud User API","version":"1.0.1","hostname":"deployment-cloud-user-65fb8d79fd-m8xv4","dbUrl":"jdbc:mysql://192.168.0.42:3306/demo_cloud_user?useUnicode=true&characterEncoding=utf-8&useSSL=false&allowPub/ # curl clusterip-cloud-user:8080/actuator/info
{"app":"Cloud User API","version":"1.0.1","hostname":"deployment-cloud-user-65fb8d79fd-28vmn","dbUrl":"jdbc:mysql://192.168.0.42:3306/demo_cloud_user?useUnicode=true&characterEncoding=utf-8&useSSL=false&allowPub/ # curl clusterip-cloud-user:8080/actuator/info
{"app":"Cloud User API","version":"1.0.1","hostname":"deployment-cloud-user-65fb8d79fd-9rjln","dbUrl":"jdbc:mysql://192.168.0.42:3306/demo_cloud_user?useUnicode=true&characterEncoding=utf-8&useSSL=false&allowPub/ # curl clusterip-cloud-user:8080/actuator/info
{"app":"Cloud User API","version":"1.0.1","hostname":"deployment-cloud-user-65fb8d79fd-9rjln","dbUrl":"jdbc:mysql://192.168.0.42:3306/demo_cloud_user?useUnicode=true&characterEncoding=utf-8&useSSL=false&allowPublicKeyRetrieval=true","description":"This is a simple Spring Boot application to demonstrate the use of BigQuery in GCP."}

虽然ping 是无法ping 通的，可能没开通ICMP 协议

但是我们的确可以通过 clusterip的service 去访问 cloud-user 的4个instance ，而且是随机分配的，时间了load balance的功能！

部署 Service A - bq-api-service

修改配置

部署之前，我们在 bq-api-service 先增加1个接口 /ext-service/user-service/info
在这个接口内，会调用 cloud-user 的 /actuator/info 接口

方便测试

Controller

    @Autowired
    private UserService userService;

    @GetMapping("/user-service/info")
    public ResponseEntity<ApiResponse<ServiceInfoDao>> userServiceInfo() {
        ServiceInfoDao userServiceInfo = null;
        try {
            userServiceInfo = this.userService.getServiceInfo();
            ApiResponse<ServiceInfoDao> response = new ApiResponse<>();
            response.setData(userServiceInfo);
            response.setReturnCode(0);
            response.setReturnMsg("user service is running in the host: " + userServiceInfo.getHostname());
            return ResponseEntity.ok(response);
        } catch (Exception e) {
            log.error("Error in getUserById...", e);
            ApiResponse<ServiceInfoDao> response = new ApiResponse<>();
            response.setReturnCode(-1);
            response.setReturnMsg("Error in getting user service info: " + e.getMessage());
            return ResponseEntity.status(500).body(response);
        }
    }

Service

    @Override
    public ServiceInfoDao getServiceInfo() {
        log.info("getServiceInfo()...");
        return userClient.getServiceInfo();
    }

feignclient:

@FeignClient(name = "demo-cloud-user", url="${hostIp.cloud-user}")
public interface UserClient {

    @GetMapping("/actuator/info")
    ServiceInfoDao getServiceInfo();
}

在feign client里见到 ip address 是配置在配置文件中的。
正好，我们增加1个新的application-k8s 配置文件
application-k8s.yaml

## 其他配置

hostIp:
  cloud-user: clusterip-cloud-user:8080

关键我们不需要再指定 cloud-user 部署在哪里的ip了，也不用关心它有多少instance, 跟spring cloud 用法很类似，只需要提供1个名字

在spring cloud 中我们需要提供cloud-user 在eureka注册的名字
在k8s 我们需要提供用于反向代理的 clusterIP service 的名字

部署docker image 上GAR

同样的方法
url： europe-west2-docker.pkg.dev/jason-hsbc/my-docker-repo/bq-api-service:xxx

编写yaml

deployment-bq-api-service.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  labels: # label of this deployment
    app: bq-api-service # custom defined
    author: Jason
  name: deployment-bq-api-service # name of this deployment
  namespace: default
spec:
  replicas: 4            # desired replica count, Please note that the replica Pods in a Deployment are typically distributed across multiple nodes.
  revisionHistoryLimit: 10 # The number of old ReplicaSets to retain to allow rollback
  selector: # label of the Pod that the Deployment is managing,, it's mandatory, without it , we will get this error 
            # error: error validating data: ValidationError(Deployment.spec.selector): missing required field "matchLabels" in io.k8s.apimachinery.pkg.apis.meta.v1.LabelSelector ..
    matchLabels:
      app: bq-api-service
  strategy: # Strategy of upodate
    type: RollingUpdate # RollingUpdate or Recreate
    rollingUpdate:
      maxSurge: 25% # The maximum number of Pods that can be created over the desired number of Pods during the update
      maxUnavailable: 25% # The maximum number of Pods that can be unavailable during the update
  template: # Pod template
    metadata:
      labels:
        app: bq-api-service # label of the Pod that the Deployment is managing. must match the selector, otherwise, will get the error Invalid value: map[string]string{"app":"bq-api-xxx"}: `selector` does not match template `labels`
    spec:
      containers:
      - image: europe-west2-docker.pkg.dev/jason-hsbc/my-docker-repo/bq-api-service:1.2.1 # image of the container
        imagePullPolicy: IfNotPresent
        name: container-bq-api-service
        env: # set env varaibles
        - name: APP_ENVIRONMENT
          value: k8s
      restartPolicy: Always # Restart policy for all containers within the Pod
      terminationGracePeriodSeconds: 10 # The period of time in seconds given to the Pod to terminate gracefully

同样4个实例，注意的是环境变量要正确地配置成 k8s`

        env: # set env varaibles
        - name: APP_ENVIRONMENT
          value: k8s

部署yaml

deployment.apps/deployment-bq-api-service created
[gateman@manjaro-x13 bq-api-service]$ kubectl get po -o wide
NAME                                        READY   STATUS    RESTARTS   AGE    IP             NODE        NOMINATED NODE   READINESS GATES
deployment-bq-api-service-778cf8f54-677vl   1/1     Running   0          34s    10.244.2.136   k8s-node0   <none>           <none>
deployment-bq-api-service-778cf8f54-nfzhg   1/1     Running   0          34s    10.244.3.77    k8s-node3   <none>           <none>
deployment-bq-api-service-778cf8f54-q9lfx   1/1     Running   0          34s    10.244.1.68    k8s-node1   <none>           <none>
deployment-bq-api-service-778cf8f54-z72dr   1/1     Running   0          34s    10.244.3.78    k8s-node3   <none>           <none>
deployment-cloud-user-65fb8d79fd-28vmn      1/1     Running   0          121m   10.244.2.133   k8s-node0   <none>           <none>
deployment-cloud-user-65fb8d79fd-9rjln      1/1     Running   0          121m   10.244.2.134   k8s-node0   <none>           <none>
deployment-cloud-user-65fb8d79fd-m8xv4      1/1     Running   0          121m   10.244.1.67    k8s-node1   <none>           <none>
deployment-cloud-user-65fb8d79fd-ndvjb      1/1     Running   0          121m   10.244.3.76    k8s-node3   <none>           <none>
dns-test                                    1/1     Running   0          105m   10.244.2.135   k8s-node0   <none>           <none>

可以见到 4个 bq-api-service 的pods 也起来了

初步测试

因为没有nodeport ，我们还是需要进入测试容器

kubectl exec -it dns-test -- /bin/sh

还是单独地测试1个instance, 先记住2个ip 10.244.2.136， 10.244.3.77

先测试该service 的info

/ # curl 10.244.2.136:8080/actuator/info
{"app":"Sales API","version":"1.2.1","hostname":"deployment-bq-api-service-778cf8f54-677vl","description":"This is a simple Spring Boot application to demonstrate the use of BigQuery in GCP."}

可以见到是已经启动了

然后在测试它的 /ext-service/user-service/info 接口

/ # curl 10.244.3.77:8080/ext-service/user-service/info
{"returnCode":0,"returnMsg":"user service is running in the host: deployment-cloud-user-65fb8d79fd-m8xv4","data":{"app":"Cloud User API","version":"1.0.1","description":"This is a simple Spring Boot application to demonstrate the use of BigQuery in GCP.","hostname":"deployment-cloud-user-65fb8d79fd-m8xv4","dbUrl":"jdbc:mysql://192.168.0.42:3306/demo_cloud_user?useUnicode=true&characterEncoding=utf-8&useSSL=false&allowP/ # curl 10.244.3.77:8080/ext-service/user-service/info
{"returnCode":0,"returnMsg":"user service is running in the host: deployment-cloud-user-65fb8d79fd-m8xv4","data":{"app":"Cloud User API","version":"1.0.1","description":"This is a simple Spring Boot application to demonstrate the use of BigQuery in GCP.","hostname":"deployment-cloud-user-65fb8d79fd-m8xv4","dbUrl":"jdbc:mysql://192.168.0.42:3306/demo_cloud_user?useUnicode=true&characterEncoding=utf-8&useSSL=false&allowP/ # curl 10.244.3.77:8080/ext-service/user-service/info
{"returnCode":0,"returnMsg":"user service is running in the host: deployment-cloud-user-65fb8d79fd-m8xv4","data":{"app":"Cloud User API","version":"1.0.1","description":"This is a simple Spring Boot application to demonstrate the use of BigQuery in GCP.","hostname":"deployment-cloud-user-65fb8d79fd-m8xv4","dbUrl":"jdbc:mysql://192.168.0.42:3306/demo_cloud_user?useUnicode=true&characterEncoding=utf-8&useSSL=false&allowP/ # curl 10.244.3.77:8080/ext-service/user-service/info
{"returnCode":0,"returnMsg":"user service is running in the host: deployment-cloud-user-65fb8d79fd-m8xv4","data":{"app":"Cloud User API","version":"1.0.1","description":"This is a simple Spring Boot application to demonstrate the use of BigQuery in GCP.","hostname":"deployment-cloud-user-65fb8d79fd-m8xv4","dbUrl":"jdbc:mysql://192.168.0.42:3306/demo_cloud_user?useUnicode=true&characterEncoding=utf-8&useSSL=false&allowP/ # curl 10.244.2.136:8080/ext-service/user-service/info
{"returnCode":0,"returnMsg":"user service is running in the host: deployment-cloud-user-65fb8d79fd-28vmn","data":{"app":"Cloud User API","version":"1.0.1","description":"This is a simple Spring Boot application to demonstrate the use of BigQuery in GCP.","hostname":"deployment-cloud-user-65fb8d79fd-28vmn","dbUrl":"jdbc:mysql://192.168.0.42:3306/demo_cloud_user?useUnicode=true&characterEncoding=utf-8&useSSL=false&allowP/ # curl 10.244.2.136:8080/ext-service/user-service/info
{"returnCode":0,"returnMsg":"user service is running in the host: deployment-cloud-user-65fb8d79fd-28vmn","data":{"app":"Cloud User API","version":"1.0.1","description":"This is a simple Spring Boot application to demonstrate the use of BigQuery in GCP.","hostname":"deployment-cloud-user-65fb8d79fd-28vmn","dbUrl":"jdbc:mysql://192.168.0.42:3306/demo_cloud_user?useUnicode=true&characterEncoding=utf-8&useSSL=false&allowP/ # curl 10.244.2.136:8080/ext-service/user-service/info
{"returnCode":0,"returnMsg":"user service is running in the host: deployment-cloud-user-65fb8d79fd-28vmn","data":{"app":"Cloud User API","version":"1.0.1","description":"This is a simple Spring Boot application to demonstrate the use of BigQuery in GCP.","hostname":"deployment-cloud-user-65fb8d79fd-28vmn","dbUrl":"jdbc:mysql://192.168.0.42:3306/demo_cloud_user?useUnicode=true&characterEncoding=utf-8&useSSL=false&allowP/ # curl 10.244.2.136:8080/ext-service/user-service/info
{"returnCode":0,"returnMsg":"user service is running in the host: deployment-cloud-user-65fb8d79fd-28vmn","data":{"app":"Cloud User API","version":"1.0.1","description":"This is a simple Spring Boot application to demonstrate the use of BigQuery in GCP.","hostname":"deployment-cloud-user-65fb8d79fd-28vmn","dbUrl":"jdbc:mysql://192.168.0.42:3306/demo_cloud_user?useUnicode=true&characterEncoding=utf-8&useSSL=false&allowPublicKeyRetrieval=true"}}/ #

可见bq-api-service 已经成功通过 cluster ip 去访问后面的cloud-user service 了，根据返回的host name

可以看出
clusterip 的loadbalancer 不会无脑随机转发

从 10.244.3.77 访问的bq-api-service 会访问 deployment-cloud-user-65fb8d79fd-m8xv4 里的cloud-user
从 10.244.2.136 访问的就会访问 deployment-cloud-user-65fb8d79fd-28vmn

为什么？因为clusterip 会智能地优先访问同1个node的后台服务！

到这了这一步，我们已经成功demo了 ClusterIP 的主要功能了
service A 已经能通过 cluster ip 访问service B 只是差了NodePort 无法从集群外测试
在这里插入图片描述

部署 NodePort nodeport-bq-api-service

注意这个nodeport 是for service A(bq-api-service)的而不是 service B，如上图

编写yaml

nodeport-bq-api-service.yaml

apiVersion: v1 #  api version can be v1 or apps/v1
kind: Service 
metadata:
  name: nodeport-bq-api-service # name of the service
  labels:
    app: bq-api-service # label of the service itself
spec:
  selector: # Label of the Pod that the Service is selecting ,  all the pods not matter the pods are belong to which deployment, as long as the pods have the label app: bq-api-service
    app: bq-api-service # if the pod do not have the label app: bq-api-service, the pod could not be selected by the service
  ports:
  - port: 8080 # port of the service itself. we could also use serviceip:port to access the pod service, 
                 # but we use the nodeip:nodePort to access the service it. this nodePort is generated by k8s ramdomly
    targetPort: 8080 # port of the Pod
    name: 8080-port # name of the port
  type: NodePort # type of the service, NodePort, ClusterIP, LoadBalancer
                 # Ramdomly start a port (30000-32767) on each node, and forward the request to the service port (32111) on the pod
                 # and it could also be use to expose the service to the external world, but it's not recommended for production, because it's not secure and low efficient

部署yaml

[gateman@manjaro-x13 bq-api-service]$ kubectl create -f nodeport-bq-api-service.yaml 
service/nodeport-bq-api-service created
[gateman@manjaro-x13 bq-api-service]$ kubectl get svc -o wide
NAME                      TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)          AGE   SELECTOR
clusterip-cloud-user      ClusterIP   10.96.11.18     <none>        8080/TCP         86m   app=cloud-user
kubernetes                ClusterIP   10.96.0.1       <none>        443/TCP          77d   <none>
nodeport-bq-api-service   NodePort    10.106.59.100   <none>        8080:32722/TCP   13s   app=bq-api-service
[gateman@manjaro-x13 bq-api-service]$ kubectl get ep -o wide
NAME                      ENDPOINTS                                                          AGE
clusterip-cloud-user      10.244.1.67:8080,10.244.2.133:8080,10.244.2.134:8080 + 1 more...   86m
kubernetes                192.168.0.3:6443                                                   77d
nodeport-bq-api-service   10.244.1.68:8080,10.244.2.136:8080,10.244.3.77:8080 + 1 more...    19s

从nodeport service 的信息得出， 1个随机端口 32722 生成用于外部访问

E2E 测试

既然所有components 都部署了，现在我们可以直接从集群外部测试
34.142.xxxxxx 是k8s-master 的公网ip

[gateman@manjaro-x13 bq-api-service]$ curl 34.142.xxxxxx:32722/actuator/info
{"app":"Sales API","version":"1.2.1","hostname":"deployment-bq-api-service-778cf8f54-z72dr","description":"This is a simple Spring Boot application to demonstrate the use of BigQuery in GCP."}[gateman@manjaro-x13 bq-api-service]$ curl 34.142.35.168:32722/ext-service/user-service/info
{"returnCode":0,"returnMsg":"user service is running in the host: deployment-cloud-user-65fb8d79fd-9rjln","data":{"app":"Cloud User API","version":"1.0.1","description":"This is a simple Spring Boot application to demonstrate the use of BigQuery in GCP.","hostname":"deployment-cloud-user-65fb8d79fd-9rjln","dbUrl":"jdbc:mysql://192.168.0.42:3306/demo_cloud_user?useUnicode=true&characterEncoding=utf-8&useSSL=false&allowPublicKeyRetrieval=true"}}[gateman@manjaro-x13 bq-api-service]$

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