网关如何连接Kubernetes中的其他服务？

Question

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I am attaching the image of my application flow. Here the Gateway and other services are created using NestJS. The request for any API comes through the gateway.

The Gateway-pod and API-pod communicate using TCP protocol .

After deployment the Gateway is not able to discover any API pods.

I am attaching the YAML image file also for both Gateway & Pods . Please do let me know what mistake I am doing in the YAML file.

                    **APPLICATION DIAGRAM**

Gateway YAML

apiVersion: apps/v1
kind: Deployment
metadata:
  namespace: roushan
  name: gateway-deployment
spec:
  replicas: 1
  selector:
    matchLabels:
      app: roushan-app
  template:
    metadata:
      labels:
        app: roushan-app
    spec:
      containers:
        - name: gateway-container
          image: nest-api-gateway:v8
          ports:
          - containerPort: 1000

---

apiVersion: v1
kind: Service
metadata:
  namespace: roushan
  name: gateway-svc
spec:
  selector:
    app: roushan-app
  ports:
    - name: gateway-svc-container
      protocol: TCP
      port: 80
      targetPort: 1000
  type: LoadBalancer

Pod YAML

apiVersion: apps/v1
kind: Deployment
metadata:
  namespace: roushan
  name: pod1-deployment
spec:
  replicas: 1
  selector:
    matchLabels:
      app: roushan-app
  template:
    metadata:
      labels:
        app: roushan-app
    spec:
      containers:
        - name: pod1-container
          image: nest-api-pod1:v2
          ports:
          - containerPort: 4000

---

apiVersion: v1
kind: Service
metadata:
   namespace: roushan
   name: pod1-srv
spec:
  selector:
    app: roushan-app
  ports:
    - name: pod1-svc-container
      protocol: TCP
      port: 80
      targetPort: 4000

Answer 1

the gateway should be able to access the services by their DNS name. for example pod1-srv.svc.cluster.local, if this does not work you may need to look at the Kubernetes DNS setup.

I have not used AKS, they may use a different domain name for the cluster other than svc.cluster.local

Answer 2

YAML Points

Ideally, you should be keeping the different selectors across the deployment .

You are using the same selectors for both deployments. Gateway and application deployment.

Service will forward the traffic to deployment based on selectors and labels, this might redirect the service-2 request to POD-1 .

Networking

You gateway service(Pods) connect to internal service by just service-name like: pod1-srv if in same namespaces.

if gateway and application in different namespaces you have to call each other like http://<servicename>.<namespace>.svc.cluster.local