如何在K8S集群内部中前后连接(拒绝连接)

deploy-front.yml apiVersion: apps/v1 # for versions before 1.9.0 use apps/v1beta2kind: Deploymentmetadata: name: gbpd-frontspec: selector: matchLabels: app: gbpd-api tier: frontend track: stable replicas: 2 template: metadata: labels: app: gbpd-api tier: frontend track: stable spec: containers: - name: react image: binomio/gbpd-front:k8s-3 ports: - containerPort: 3000 resources: limits: memory: "150Mi" requests: memory: "100Mi" imagePullPolicy: Always service-front.yaml apiVersion: v1kind: Servicemetadata: name: gbpd-frontspec: selector: app: gbpd-api tier: frontend ports: - protocol: "TCP" port: 3000 targetPort: 3000 type: LoadBalancer Deploy-back.yaml apiVersion: apps/v1 # for versions before 1.9.0 use apps/v1beta2kind: Deploymentmetadata: name: gbpd-apispec: selector: matchLabels: app: gbpd-api tier: backend track: stable replicas: 3 # tells deployment to run 2 pods matching the template template: metadata: labels: app: gbpd-api tier: backend track: stable spec: containers: - name: gbpd-api image: binomio/gbpd-back:dev ports: - name: http containerPort: 3008 service-back.yaml apiVersion: v1kind: Servicemetadata: name: gbpd-apispec: selector: app: gbpd-api tier: backend ports: - protocol: "TCP" port: 3008 targetPort: http 我尝试了许多组合，还尝试将"LoadBalancer"添加到backservice中，但是什么也没有...我可以将perfecto连接到localhost:3000并使用前端，但是前端无法连接到后端服务. 问题1 :要通过REACT_APP_API_URL正确进行设置，要使用的IP/名称是什么?问题2 :为什么curl localhost:3008没有回答?经过2天的尝试，几乎可以尝试k8s官方文档中的所有内容...无法弄清这里发生了什么，因此任何帮助将不胜感激. kubectl描述svc gbpd-api响应:kubectl describe svc gbpd-apiName: gbpd-apiNamespace: defaultLabels: <none>Annotations: kubectl.kubernetes.io/last-applied-configuration: {"apiVersion":"v1","kind":"Service","metadata":{"annotations":{},"name":"gbpd-api","namespace":"default"},"spec":{"ports":[{"port":3008,"p...Selector: app=gbpd-api,tier=backendType: LoadBalancerIP: 10.107.145.227LoadBalancer Ingress: localhostPort: <unset> 3008/TCPTargetPort: http/TCPNodePort: <unset> 31464/TCPEndpoints: 10.1.1.48:3008,10.1.1.49:3008,10.1.1.50:3008Session Affinity: NoneExternal Traffic Policy: ClusterEvents: <none>解决方案我测试了您的环境，并且在使用Nginx图像时它可以正常工作，让我们回顾一下环境:正确描述了前端部署.前端服务将其公开为负载均衡器，这意味着您可以从外部轻松访问前端.还正确描述了后端部署.后端服务与ClusterIP一起使用，以便只能从群集内部访问.下面，我将演示前端和后端之间的通信.我使用的是您提供的相同Yaml，出于示例目的，仅将图像更改为Nginx，并且由于它是http服务器，因此我将Containerport更改为80. 问题1:为了传递REACT_APP_API_URL正确进行前端访问，要使用的ip/名称是什么?我已根据要求将ENV变量添加到前端部署中，并且还将使用它进行演示.您必须使用服务名称进行卷曲，而我使用的是简短版本，因为我们使用的是同一名称空间.您也可以使用全名: http://gbpd-api.default.svc. cluster.local:3008 复制:创建Yaml并应用它们:$ cat deploy-front.yamlapiVersion: apps/v1kind: Deploymentmetadata: name: gbpd-frontspec: selector: matchLabels: app: gbpd-api tier: frontend track: stable replicas: 2 template: metadata: labels: app: gbpd-api tier: frontend track: stable spec: containers: - name: react image: nginx env: - name: REACT_APP_API_URL value: http://gbpd-api:3008 ports: - containerPort: 80 resources: limits: memory: "150Mi" requests: memory: "100Mi" imagePullPolicy: Always$ cat service-front.yamlcat: cat: No such file or directoryapiVersion: v1kind: Servicemetadata: name: gbpd-frontspec: selector: app: gbpd-api tier: frontend ports: - protocol: "TCP" port: 3000 targetPort: 80 type: LoadBalancer$ cat deploy-back.yamlapiVersion: apps/v1kind: Deploymentmetadata: name: gbpd-apispec: selector: matchLabels: app: gbpd-api tier: backend track: stable replicas: 3 template: metadata: labels: app: gbpd-api tier: backend track: stable spec: containers: - name: gbpd-api image: nginx ports: - name: http containerPort: 80$ cat service-back.yamlapiVersion: v1kind: Servicemetadata: name: gbpd-apispec: selector: app: gbpd-api tier: backend ports: - protocol: "TCP" port: 3008 targetPort: http$ kubectl apply -f deploy-front.yamldeployment.apps/gbpd-front created$ kubectl apply -f service-front.yamlservice/gbpd-front created$ kubectl apply -f deploy-back.yamldeployment.apps/gbpd-api created$ kubectl apply -f service-back.yamlservice/gbpd-api created请记住，在Kubernetes中，通信是设计为在服务，因为当部署发生更改或Pod发生故障时，总是会重新创建Pod.$ kubectl get allNAME READY STATUS RESTARTS AGEpod/gbpd-api-dc5b4b74b-kktb9 1/1 Running 0 41mpod/gbpd-api-dc5b4b74b-mzpbg 1/1 Running 0 41mpod/gbpd-api-dc5b4b74b-t6qxh 1/1 Running 0 41mpod/gbpd-front-66b48f8b7c-4zstv 1/1 Running 0 30mpod/gbpd-front-66b48f8b7c-h58ds 1/1 Running 0 31mNAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGEservice/gbpd-api ClusterIP 10.0.10.166 <none> 3008/TCP 40mservice/gbpd-front LoadBalancer 10.0.11.78 35.223.4.218 3000:32411/TCP 42m这些Pod是工作人员，由于它们可以自然替换，因此我们将连接到前端Pod以模拟他的行为，并尝试连接到后端服务(该网络层会将流量定向到其中一个后端容器). nginx映像未预装curl，因此出于演示目的，我将必须安装它:$ kubectl exec -it pod/gbpd-front-66b48f8b7c-4zstv -- /bin/bashroot@gbpd-front-66b48f8b7c-4zstv:/# apt update && apt install curl -ydone.root@gbpd-front-66b48f8b7c-4zstv:/# curl gbpd-api:3008<!DOCTYPE html><html><head><title>Welcome to nginx!</title>...现在让我们尝试使用定义的环境变量:root@gbpd-front-66b48f8b7c-4zstv:/# printenv | grep REACTREACT_APP_API_URL=http://gbpd-api:3008root@gbpd-front-66b48f8b7c-4zstv:/# curl $REACT_APP_API_URL<!DOCTYPE html><html><head><title>Welcome to nginx!</title>... 注意事项: 问题2:为什么curl localhost:3008没有回答?由于正确描述了所有Yaml，因此必须检查image: binomio/gbpd-back:dev是否在预期的端口3008上正确提供了服务.由于它不是公共图像，因此我无法对其进行测试，因此，我将向您提供故障排除步骤:就像我们登录前端pod一样，您必须登录到此后端pod并测试curl localhost:3008.如果它基于带有apt-get的Linux发行版，则可以像在演示中一样运行命令:从后端部署获取pod名称(例如:gbpd-api-6676c7695c-6bs5n)运行kubectl exec -it pod/<POD_NAME> -- /bin/bash然后运行apt update && apt install curl -y并测试curl localhost:3008如果没有答案，请运行"apt update&&& apt安装net-tools并测试netstat -nlpt，它将必须向您显示正在运行的服务的输出以及相应的端口，例如:root@gbpd-api-585df9cb4d-xr6nk:/# netstat -nlptActive Internet connections (only servers)Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program nametcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN 1/nginx: master pro如果即使采用这种方法，吊舱也没有返回任何内容，则您将不得不检查图像中的代码.让我知道之后是否需要帮助！Error while trying to connect React frontend web to nodejs express api server into kubernetes cluster.Can navigate in browser to http:localhost:3000 and web site is ok.But can't navigate to http:localhost:3008 as expected (should not be exposed)My goal is to pass REACT_APP_API_URL environment variable to frontend in order to set axios baseURL and be able to establish communication between front and it's api server.deploy-front.ymlapiVersion: apps/v1 # for versions before 1.9.0 use apps/v1beta2kind: Deploymentmetadata: name: gbpd-frontspec: selector: matchLabels: app: gbpd-api tier: frontend track: stable replicas: 2 template: metadata: labels: app: gbpd-api tier: frontend track: stable spec: containers: - name: react image: binomio/gbpd-front:k8s-3 ports: - containerPort: 3000 resources: limits: memory: "150Mi" requests: memory: "100Mi" imagePullPolicy: Alwaysservice-front.yamlapiVersion: v1kind: Servicemetadata: name: gbpd-frontspec: selector: app: gbpd-api tier: frontend ports: - protocol: "TCP" port: 3000 targetPort: 3000 type: LoadBalancerDeploy-back.yamlapiVersion: apps/v1 # for versions before 1.9.0 use apps/v1beta2kind: Deploymentmetadata: name: gbpd-apispec: selector: matchLabels: app: gbpd-api tier: backend track: stable replicas: 3 # tells deployment to run 2 pods matching the template template: metadata: labels: app: gbpd-api tier: backend track: stable spec: containers: - name: gbpd-api image: binomio/gbpd-back:dev ports: - name: http containerPort: 3008service-back.yamlapiVersion: v1kind: Servicemetadata: name: gbpd-apispec: selector: app: gbpd-api tier: backend ports: - protocol: "TCP" port: 3008 targetPort: httpI tried many combinations, also tried adding "LoadBalancer" to backservice but nothing...I can connect perfecto to localhost:3000 and use frontend but frontend can't connect to backend service.Question 1: What's is the ip/name to use in order to pass REACT_APP_API_URL to fronten correctly?Question 2: Why is curl localhost:3008 not answering?After 2 days trying almost everything in k8s official docs... can't figure out what's happening here, so any help will be much appreciated.kubectl describe svc gbpd-apiResponse:kubectl describe svc gbpd-apiName: gbpd-apiNamespace: defaultLabels: <none>Annotations: kubectl.kubernetes.io/last-applied-configuration: {"apiVersion":"v1","kind":"Service","metadata":{"annotations":{},"name":"gbpd-api","namespace":"default"},"spec":{"ports":[{"port":3008,"p...Selector: app=gbpd-api,tier=backendType: LoadBalancerIP: 10.107.145.227LoadBalancer Ingress: localhostPort: <unset> 3008/TCPTargetPort: http/TCPNodePort: <unset> 31464/TCPEndpoints: 10.1.1.48:3008,10.1.1.49:3008,10.1.1.50:3008Session Affinity: NoneExternal Traffic Policy: ClusterEvents: <none> 解决方案 I tested your environment, and it worked when using a Nginx image, let's review the environment:The front-deployment is correctly described.The front-service exposes it as loadbalancer, meaning your frontend is accessible from outside, perfect.The back deployment is also correctly described.The backend-service stays with as ClusterIP in order to be only accessible from inside the cluster, great.Below I'll demonstrate the communication between front-end and back end.I'm using the same yamls you provided, just changed the image to Nginx for example purposes, and since it's a http server I'm changing containerport to 80. Question 1: What's is the ip/name to use in order to pass REACT_APP_API_URL to fronten correctly?I added the ENV variable to the front deploy as requested, and I'll use it to demonstrate also. You must use the service name to curl, I used the short version because we are working in the same namespace. you can also use the full name: http://gbpd-api.default.svc.cluster.local:3008Reproduction:Create the yamls and applied them:$ cat deploy-front.yamlapiVersion: apps/v1kind: Deploymentmetadata: name: gbpd-frontspec: selector: matchLabels: app: gbpd-api tier: frontend track: stable replicas: 2 template: metadata: labels: app: gbpd-api tier: frontend track: stable spec: containers: - name: react image: nginx env: - name: REACT_APP_API_URL value: http://gbpd-api:3008 ports: - containerPort: 80 resources: limits: memory: "150Mi" requests: memory: "100Mi" imagePullPolicy: Always$ cat service-front.yamlcat: cat: No such file or directoryapiVersion: v1kind: Servicemetadata: name: gbpd-frontspec: selector: app: gbpd-api tier: frontend ports: - protocol: "TCP" port: 3000 targetPort: 80 type: LoadBalancer$ cat deploy-back.yamlapiVersion: apps/v1kind: Deploymentmetadata: name: gbpd-apispec: selector: matchLabels: app: gbpd-api tier: backend track: stable replicas: 3 template: metadata: labels: app: gbpd-api tier: backend track: stable spec: containers: - name: gbpd-api image: nginx ports: - name: http containerPort: 80$ cat service-back.yamlapiVersion: v1kind: Servicemetadata: name: gbpd-apispec: selector: app: gbpd-api tier: backend ports: - protocol: "TCP" port: 3008 targetPort: http$ kubectl apply -f deploy-front.yamldeployment.apps/gbpd-front created$ kubectl apply -f service-front.yamlservice/gbpd-front created$ kubectl apply -f deploy-back.yamldeployment.apps/gbpd-api created$ kubectl apply -f service-back.yamlservice/gbpd-api createdRemember, in Kubernetes the communication is designed to be made between services, because the pods are always recreated when there is a change in the deployment or when the pod fail.$ kubectl get allNAME READY STATUS RESTARTS AGEpod/gbpd-api-dc5b4b74b-kktb9 1/1 Running 0 41mpod/gbpd-api-dc5b4b74b-mzpbg 1/1 Running 0 41mpod/gbpd-api-dc5b4b74b-t6qxh 1/1 Running 0 41mpod/gbpd-front-66b48f8b7c-4zstv 1/1 Running 0 30mpod/gbpd-front-66b48f8b7c-h58ds 1/1 Running 0 31mNAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGEservice/gbpd-api ClusterIP 10.0.10.166 <none> 3008/TCP 40mservice/gbpd-front LoadBalancer 10.0.11.78 35.223.4.218 3000:32411/TCP 42mThe pods are the workers, and since they are replaceable by nature, we will connect to a frontend pod to simulate his behaviour and try to connect to the backend service (which is the network layer that will direct the traffic to one of the backend pods).The nginx image does not come with curl preinstalled, so I will have to install it for demonstration purposes:$ kubectl exec -it pod/gbpd-front-66b48f8b7c-4zstv -- /bin/bashroot@gbpd-front-66b48f8b7c-4zstv:/# apt update && apt install curl -ydone.root@gbpd-front-66b48f8b7c-4zstv:/# curl gbpd-api:3008<!DOCTYPE html><html><head><title>Welcome to nginx!</title>...Now let's try using the environment variable that was defined:root@gbpd-front-66b48f8b7c-4zstv:/# printenv | grep REACTREACT_APP_API_URL=http://gbpd-api:3008root@gbpd-front-66b48f8b7c-4zstv:/# curl $REACT_APP_API_URL<!DOCTYPE html><html><head><title>Welcome to nginx!</title>...Considerations: Question 2: Why is curl localhost:3008 not answering?Since all yamls are correctly described you must check if image: binomio/gbpd-back:dev is correctly serving on port 3008 as intended.Since it's not a public image, I can't test it, so I'll give you troubleshooting steps:just like we logged inside the front-end pod you will have to log into this backend-pod and test curl localhost:3008.If it's based on a linux distro with apt-get, you can run the commands just like I did on my demo:get the pod name from backend deploy (example: gbpd-api-6676c7695c-6bs5n)run kubectl exec -it pod/<POD_NAME> -- /bin/bashthen run apt update && apt install curl -yand test curl localhost:3008if no answer run `apt update && apt install net-toolsand test netstat -nlpt, it will have to show you the output of the services running and the respective port, example:root@gbpd-api-585df9cb4d-xr6nk:/# netstat -nlptActive Internet connections (only servers)Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program nametcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN 1/nginx: master proIf the pod does not return nothing even on this approach, you will have to check the code in the image.Let me know if you need help after that! 这篇关于如何在K8S集群内部中前后连接(拒绝连接)的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！ 上岸，阿里云！