NodePort service is not externally accessible via `port` number

Question

I have following service configuration:

kind: Service
apiVersion: v1
metadata:
  name: web-srv
spec:
  type: NodePort
  selector:
    app: userapp
    tier: web
  ports:
    - protocol: TCP
      port: 8090
      targetPort: 80
      nodePort: 31000

and an nginx container is behind this service. Although I can access to the service via nodePort, service is not accessible via port field. I'm able to see the configs with kubectl and Kubernetes dashboard but curling to that port (e.g. curl http://192.168.0.100:8090) raises a Connection Refused error.

I'm not sure what is the problem here. Do I need to make sure any proxy services is running inside the Node or Container?

Answer 1

Get the IP of the kubernetes service and then hit 8090; it will work. nodePort implies that the service is bound to the node at port 31000.

These are the 3 things that will work:

curl <node-ip>:<node-port>        # curl <node-ip>:31000
curl <service-ip>:<service-port>  # curl <svc-ip>:8090
curl <pod-ip>:<target-port>       # curl <pod-ip>:80

So now, let's look at 3 situations:

1. You are inside the kubernetes cluster (you are a pod)

<service-ip> and <pod-ip> and <node-ip> will work.

2. You are on the node

<service-ip> and <pod-ip> and <node-ip> will work.

3. You are outside the node

Only <node-ip> will work assuming that <node-ip> is reachable.