We are trying to implement WebSocket in Kubernetes by following steps given in GCP document "https://cloud.google.com/kubernetes-engine/docs/concepts/ingress#support_for_websocket" & "https://cloud.google.com/kubernetes-engine/docs/how-to/configure-backend-service" . but we are getting "Error during WebSocket handshake: Unexpected response code: 502”.

Error Message : “WebSocket connection to 'wss://..../backend-channeladaptor-web/socket.io/?EIO=3&transport=websocket' failed: Error during WebSocket handshake: Unexpected response code: 502”.

I have also attached Files created for gke implementation:

1. Backend-channeladaptor-web.yaml

   • Deployment content

   • Service content

   • Backendconfig content

2. Converse-ingress.yaml (It has details of other services as well you can ignore that except backend-channeladaptor-web).

Converse-ingress.yaml

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: converse-ingress
  annotations:
    kubernetes.io/ingress.global-static-ip-name: $Static-Ip-Name
    kubernetes.io/ingress.allow-http: "false"
spec:
  tls:
  - secretName: $SSL-certificate
  rules:
  - host: $HostName
    http:
      paths:
      - path: /*
        backend:
          serviceName: frontend-chat-client
          servicePort: 3040
      - path: /socket-io/*
        backend:
          serviceName: backend-channeladaptor-engineerportal
          servicePort: 11009          
      - path: /login/*
        backend:
          serviceName: frontend-engineeringportal
          servicePort: 3021
      - path: /frontend-engineeringportal/*
        backend:
          serviceName: frontend-engineeringportal
          servicePort: 3021
      - path: /backend-channeladaptor-web/*
        backend:
          serviceName: backend-channeladaptor-web
          servicePort: 11006

Backend-channeladaptor-web.yaml

apiVersion: cloud.google.com/v1beta1
kind: BackendConfig
metadata:
  name: backend-channeladaptor-web-backendconfig
spec:
  timeoutSec: 3600
  connectionDraining:
    drainingTimeoutSec: 3600

---
apiVersion: v1
kind: Service
metadata:
  name: backend-channeladaptor-web
  annotations:
    beta.cloud.google.com/backend-config: '{"ports": {"8081":"backend-channeladaptor-web-backendconfig"}}'
spec:
  type: NodePort
  ports:
    - port: 8081
      targetPort: 11006
      protocol: TCP
      nodePort: 30078
      name: http
  selector:
    app: backend-channeladaptor-web

---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: backend-channeladaptor-web
spec:
  selector:
    matchLabels:
      app: backend-channeladaptor-web
  replicas: 1
  template:
    metadata:
      labels:
        app: backend-channeladaptor-web
    spec:
      containers:
        - image: gcr.io/acn-careful-granite-240620/backend-channeladaptor-web:0.2
          name: backend-channeladaptor-web
          ports:
           - name: http
             containerPort: 11006
             hostPort: 11006
          env:
            - name: NODE_ENV
              value: dev

I expect the response status code 101 but getting 502 Bad Gateway