minikube is an excellent way to have a Kubernetes server up-and-running in no time on your Ubuntu machine. In this article we’re going to have the vaadin-boot-example-maven app running in Kubernetes. That will require the following steps:

1. Create a docker image of the vaadin-boot-example-maven
2. Deploy that docker image into MiniKube docker repository.
3. Define a Kubernetes app consisting of the vaadin-boot-example-maven app and an ingress rule
4. Upload and run the app.

Install minikube and docker

First, follow the steps outlined on the MiniKube docs page, to have MiniKube up-and-running quickly. I’m running Ubuntu 24.04 arm64, so I downloaded the appropriate deb package and installed it as suggested in the minikube start page.

Start the MiniKube dashboard, to see that minikube is running: minikube dashboard.

We’ll need to install the following addons to minikube:

• ingress, to correctly reroute http traffic to the app pods
• registry to be able to have locally built docker images accessible from within the minikube.

That can be done easily:

$ minikube addons enable ingress registry

Create a docker image of vaadin-boot-example-maven

This one is easy, just git clone the project and create the docker image locally:

git clone https://github.com/mvysny/vaadin-boot-example-maven
cd vaadin-boot-example-maven
docker build --no-cache -t test/vaadin-boot-example-maven:latest .

See the project Dockerfile for more details.

Verify that the app is running correctly in Docker:

docker run --rm -ti -p8080:8080 test/vaadin-boot-example-maven

The app should start and should listen on localhost:8080.

Stop the app - we’ll run it from minikube next.

Import the test/vaadin-boot-example-maven image to minikube

Build the image again, but this time using minikube local docker (as described here):

eval $(minikube docker-env)
docker build --no-cache -t test/vaadin-boot-example-maven:latest .
minikube image ls|grep vaadin-boot

The last command will print docker.io/test/vaadin-boot-example-maven:latest if the image was built correctly.

Define Kubernetes deployments and services

We’ll need to define a pod and a service and an ingress rule for the app. The app will configure ingress to forward all traffic coming from the myapp.fake DNS domain. The easiest way to create the domain is to edit your /etc/hosts and add the rule:

192.168.49.2 myapp.fake

Note the 192.168.49.2 IP address: run minikube ip and minikube will tell you on which IP address it listens. Use that IP address.

Create a file named my-vaadin-boot-example-maven.yml with the following contents:

apiVersion: v1
kind: Namespace
metadata:
  name: my-vaadin-boot-example-maven
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: deployment
  namespace: my-vaadin-boot-example-maven
spec:
  selector:
    matchLabels:
      app: pod
  template:
    metadata:
      labels:
        app: pod
    spec:
      containers:
        - name: main
          image: test/vaadin-boot-example-maven:latest
          imagePullPolicy: Never
          ports:
            - containerPort: 8080
          resources:
            limits:
              memory: "256Mi"  # https://kubernetes.io/docs/concepts/configuration/manage-resources-containers/
              cpu: 1
---
apiVersion: v1
kind: Service
metadata:
  name: service
  namespace: my-vaadin-boot-example-maven
spec:
  selector:
    app: pod
  ports:
    - port: 8080
---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: ingress-custom-dns
  namespace: my-vaadin-boot-example-maven
spec:
  rules:
    - host: "myapp.fake"
      http:
        paths:
          - path: /
            pathType: Prefix
            backend:
              service:
                name: service
                port:
                  number: 8080

Note: if the configuration file above doesn’t make any sense, please make sure to read the Deploy your first scaleable PHP/MySQL Web application in Kubernetes article which is an excellent introduction to Kubernetes.

Run this command in order to create and activate the services and pods above:

$ kubectl apply -f my-vaadin-boot-example-maven.yml

You can go to MiniKube dashboard, to see a Pod is started, a Service is created, and an Ingress rule is created. You need to select the my-vaadin-boot-example-maven namespace first though.

To see the logs, go to Pods, then “View Logs” upper-right icon button.