Cannot connect to a socket in a Docker container running on Kubernetes - node.js

Question

I'm trying to connect to a socket that is inside a container and deployed on Kubernetes.
Locally everything works fine but when deployed it throws an error on connect. I tried with different options but with no success.
Client code
const ENDPOINT = "https://traveling.dev/api/chat"; // this will go to the endpoint of service where socket is running
const chatSocket = io(ENDPOINT, {
rejectUnauthorized: false,
forceNew: true,
secure: false,
});
chatSocket.on("connect_error", (err) => {
console.log(err);
console.log(`connect_error due to ${err.message}`);
});
console.log("CS", chatSocket);
Server code
const app = express();
app.set("trust proxy", true);
app.use(cors());
const server = http.createServer(app);
const io = new Server(server, {
cors: {
origin: "*",
methods: ["*"],
allowedHeaders: ["*"],
},
});
io.on("connection", (socket) => {
console.log("Socket succesfully connected with id: " + socket.id);
});
const start = async () => {
server.listen(3000, () => {
console.log("Started");
});
};
start();
The thing is code is irrelevant here cause locally it all works fine but I posted it anyways.
What can cause this while containerizing it and putting it on Kubernetes?
And the console log just says server error
Error: server error
at Socket.onPacket (socket.js:397)
at XHR.push../node_modules/component-emitter/index.js.Emitter.emit (index.js:145)
at XHR.onPacket (transport.js:107)
at callback (polling.js:98)
at Array.forEach (<anonymous>)
at XHR.onData (polling.js:102)
at Request.push../node_modules/component-emitter/index.js.Emitter.emit (index.js:145)
at Request.onData (polling-xhr.js:232)
at Request.onLoad (polling-xhr.js:283)
at XMLHttpRequest.xhr.onreadystatechange (polling-xhr.js:187)
Does anyone have any suggestions on what may cause this and how to fix it?
Also, any idea on how to get more information about the error would be appreciated.
This is the YAML file that creates the Service and a Pod.
apiVersion: apps/v1
kind: Deployment
metadata:
name: chat-depl
spec:
replicas: 1
selector:
matchLabels:
app: chat
template:
metadata:
labels:
app: chat
spec:
containers:
- name: chat
image: us.gcr.io/forward-emitter-321609/chat-service
---
apiVersion: v1
kind: Service
metadata:
name: chat-srv
spec:
selector:
app: chat
ports:
- name: chat
protocol: TCP
port: 3000
targetPort: 3000
I'm using a loadbalancer on GKE with nginx which IP address is mapped to traveling.dev
This is how my ingress routing service config looks like:
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: ingress-service
annotations:
kubernetes.io/ingress.class: nginx
nginx.ingress.kubernetes.io/use-regex: "true"
nginx.ingress.kubernetes.io/enable-cors: "true"
nginx.ingress.kubernetes.io/cors-allow-methods: "PUT, GET, POST, OPTIONS"
nginx.ingress.kubernetes.io/cors-allow-credentials: "true"
nginx.ingress.kubernetes.io/configuration-snippet: |
more_set_headers "Access-Control-Allow-Origin: $http_origin";
spec:
rules:
- host: traveling.dev
http:
paths:
- path: /api/chat/?(.*)
backend:
serviceName: chat-srv
servicePort: 3000
- path: /?(.*)
backend:
serviceName: client-srv
servicePort: 3000
Thanks!

Answer 1

Nginx Ingress by default support WebSocket proxying, but you need to configure it.
For this you need to add annotation custom configuration snippet.
You can refer this already answered stackoverflow question.
Nginx ingress controller websocket support