kubernetes how to open nodeport for a single host

Question

Scenario:

I have a k8s cluster with host01, host02 and host03.

I'm running master on host01 and slaves on host02 and host03, and I want to open a port for client connections on master, ie I want to open: host01:32702.

Using following service.yaml, I managed to open host01:32702. To my surprise host02:32702 and host03:32702 are also open.

kind: Service
# ...
spec:
  type: NodePort
  ports:
  - name: dashboard
    port: 8265
    targetPort: 8265
    nodePort: 32702
  selector:
    podonhost01: yes

Questions:

Is this intended NodePort behavior? Is the selector not working?
If yes, then why is this the intended NodePort behavior? If I have 1000s hosts, then single service will open port 32702 on all these hosts?
How do I only open port 32702 on host01 and not the rest of hosts?

user_5525824 · Answer

You can use the externalIP,

apiVersion: v1
kind: Service
metadata:
  name: my-service
spec:
  selector:
    app.kubernetes.io/name: MyApp
  ports:
    - name: http
      protocol: TCP
      port: 80
      targetPort: 9376
  externalIPs:
    - HOST-01 IP

Ref : https://kubernetes.io/docs/concepts/services-networking/service/#external-ips

kubernetes how to open nodeport for a single host

1 Answers