Hello Kubernetes!

This image can be deployed on a Kubernetes cluster. It displays a default Hello world! message, the name of the pod it was deployed to, and some os information about the node the pod was deployed to.

The message displayed can be overridden using the MESSAGE environment variable.

DockerHub

It is available on DockerHub as:

• paulbouwer/hello-kubernetes:1.4

Deploy

You can deploy the image to your Kubernetes cluster one of two ways:

Deploy using the hello-kubernetes.yaml, which contains definitions for the service and deployment objects:

# hello-kubernetes.yaml

apiVersion: v1
kind: Service
metadata:
  name: hello-kubernetes
spec:
  type: LoadBalancer
  ports:
  - port: 80
    targetPort: 8080
  selector:
    app: hello-kubernetes
---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: hello-kubernetes
spec:
  replicas: 3
  template:
    metadata:
      labels:
        app: hello-kubernetes
    spec:
      containers:
      - name: hello-kubernetes
        image: paulbouwer/hello-kubernetes:1.4                
        ports:
        - containerPort: 8080

$ kubectl apply -f yaml/hello-kubernetes.yaml

Or, deploy by executing the following run and expose commands on kubectl.

$ kubectl run hello-kubernetes --replicas=3 --image=paulbouwer/hello-kubernetes:1.4 --port=8080
$ kubectl expose deployment hello-kubernetes --type=LoadBalancer --port=80 --target-port=8080 --name=hello-kubernetes

This will display a Hello world! message when you hit the service endpoint in a browser. You can get the service endpoint ip address by executing the following command and grabbing the returned external ip address value:

$ kubectl get service hello-kubernetes

Custom Message

You can customise the message displayed by the hello-kubernetes container as follows:

Deploy using the hello-kubernetes.custom-message.yaml, which contains definitions for the service and deployment objects:

In the definition for the deployment, add an env variable with a name of MESSAGE. The value you provide will be displayed as the custom message.

# hello-kubernetes.custom-message.yaml

apiVersion: v1
kind: Service
metadata:
  name: hello-kubernetes-custom
spec:
  type: LoadBalancer
  ports:
  - port: 80
    targetPort: 8080
  selector:
    app: hello-kubernetes-custom
---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: hello-kubernetes-custom
spec:
  replicas: 3
  template:
    metadata:
      labels:
        app: hello-kubernetes-custom
    spec:
      containers:
      - name: hello-kubernetes
        image: paulbouwer/hello-kubernetes:1.4                
        ports:
        - containerPort: 8080
        env:
        - name: MESSAGE
          value: I just deployed this on Kubernetes!

$ kubectl apply -f yaml/hello-kubernetes.custom-message.yaml

Or, deploy by executing the following run and expose commands on kubectl, with the environment variable MESSAGE provided as part of the run command.

$ kubectl run hello-kubernetes --replicas=3 --image=paulbouwer/hello-kubernetes:1.4 --port=8080 --env="MESSAGE=I just deployed this on Kubernetes!"
$ kubectl expose deployment hello-kubernetes --type=LoadBalancer --port=80 --target-port=8080 --name=hello-kubernetes

Build

If you'd like to build the image yourself, then you can do so as follows. The build-arg parameters provide values to the Docker image labels which follow the Label Schema convention.

Bash

$ docker build --no-cache --build-arg IMAGE_VERSION="1.4" --build-arg BUILD_DATE="`date -u +"%Y-%m-%dT%H:%M:%SZ"`" --build-arg VCS_REF="`git rev-parse HEAD`" -f Dockerfile -t "hello-kubernetes:1.4" .

Powershell

PS> docker build --no-cache --build-arg IMAGE_VERSION="1.4" --build-arg BUILD_DATE="$(Get-Date((Get-Date).ToUniversalTime()) -UFormat '%Y-%m-%dT%H:%M:%SZ')" --build-arg VCS_REF="$(git rev-parse HEAD)" -f Dockerfile -t "hello-kubernetes:1.4" .