Getting Connection refused while trying to access service from kubernetes pod - node.js

Question

I am new to kubernetes and I am trying to learn it by deploying a simple node server using AWS EKS. (kubernetes is alreay setup to talk to the created AWS EKS cluster)
Here is code for my simple node file (server.js)
const express = require('express')
const app = express()
const port = 8080
app.get('/', (req, res) => {
res.send('Hello World!')
})
app.listen(port, () => {
console.log(`Example app listening at http://localhost:${port}`)
})
Here is how the Dockerfile looks like:
FROM node:12
# Create app directory
WORKDIR /usr/src/app
# Install app dependencies
COPY package*.json ./
RUN npm ci
# Bundle app source
COPY . .
EXPOSE 8080
CMD [ "node", "server.js" ]
I am able to run the above server in my local by creating a docker image.
Now, in order to deploy this server here are the steps that I followed:
First, I pushed the above image to doceker hub (aroraankit7/simple-server)
Second, I created a deployment.yaml file which looks like this:
apiVersion: apps/v1
kind: Deployment
metadata:
name: simple-server-app
labels:
app: simple-server-app
spec:
replicas: 2
selector:
matchLabels:
app: simple-server-app
template:
metadata:
labels:
app: simple-server-app
spec:
containers:
- name: simple-server
image: aroraankit7/simple-server:v1
ports:
- containerPort: 8080
Third, I deployed this using kubectl apply command. Here is the output for kubectl get pods
Then, I created the service.yaml file. Here is how it looks:
apiVersion: v1
kind: Service
metadata:
name: simple-server-svc
labels:
run: simple-server
spec:
ports:
- port: 8080
targetPort: 8080
protocol: TCP
selector:
run: simple-server
I then deployed this using the kubectl apply command. Output for kubectl describe services:
Next, I logged into on of my pods by using the command: kubectl -it exec simple-server-app-758dfb88f4-4cfmp bash
While inside this pod, I ran the following the command: curl http://simple-server-svc:8080 and this was the output that I got: curl: (7) Failed to connect to simple-server-svc port 8080: Connection refused
Why is the connection getting refused?
When I am running curl http:localhost://8080, I am getting the right output (Hello World! in this case)

Answer 1

Your service is not bound to the deployment. You need to modify the selector in your service.yaml to the following:
apiVersion: v1
kind: Service
metadata:
name: simple-server-svc
labels:
run: simple-server
spec:
ports:
- port: 8080
targetPort: 8080
protocol: TCP
selector:
app: simple-server-app
You can use kubectl expose command to avoid mistakes like this.