Kubernetes service is not getting external IP

Question

I running Kubernetes cluster on premises, initialized using KubeAdm. I configured flannel networking plugin.

When I exposing service as a NodePort, I'm not able to receive external IP. What do I miss?

My deployment yaml looks as the following:

apiVersion: v1
kind: Service
metadata:
  name: testapp
  labels:
    run: testapp
spec:
  type: NodePort
  ports:
  - port: 8080
    targetPort: 80
    protocol: TCP
    name: http
  - port: 443
    protocol: TCP
    name: https
  selector:
    run: testapp
---------
apiVersion: apps/v1
kind: Deployment
metadata:
  name: testapp
spec:
  selector:
    matchLabels:
      run: testapp
  replicas: 2
  template:
    metadata:
      name: testapp
      labels:
        run: testapp
    spec:
      containers:
        - image: [omitted]
          name: testapp
          ports:
          - containerPort: 80
             livenessProbe:
               httpGet:
               path: /api/health
               port: 80

Environment details:

Kubernetes version:

Client Version: version.Info{Major:"1", Minor:"9", GitVersion:"v1.9.3", GitCommit:"d2835416544f298c919e2ead3be3d0864b52323b", GitTreeState:"clean", BuildDate:"2018-02-07T12:22:21Z", GoVersion:"go1.9.2", Compiler:"gc", Platform:"linux/amd64"}
Server Version: version.Info{Major:"1", Minor:"9", GitVersion:"v1.9.3", GitCommit:"d2835416544f298c919e2ead3be3d0864b52323b", GitTreeState:"clean", BuildDate:"2018-02-07T11:55:20Z", GoVersion:"go1.9.2", Compiler:"gc", Platform:"linux/amd64"}

Running Ubuntu Server 16.04 on vSphere VM (on-prem).

Answer 1

You would not get an external IP when exposing service as a nodeport. Exposing Service on a Nodeport means that your service would be available on externally via the NodeIP of any node in the cluster at a random port between 30000-32767(default behaviour) .

In your case , the port on which your service is exposed is port 31727.

Each of the nodes in the cluster proxy that port (the same port number on every Node) into the pod where your service is launched.

Easiest way to see this using

kubectl describe service <service-name>

Check for detail of the Nodeport in the result above.

Later get any the node Ip of any of the nodes in the cluster using

kubectl get nodes -o wide

You can now access your service externally using <Node-IP>:<Node-Port>

Additionally, if you want a fixed Node port, you can specify that in the yaml.

PS: Just make sure you add a security rule on your nodes to allow traffic on the particular port.