How to deploy a simple Hello World program to local Kubernetes cluster

Question

I have a very simple spring-boot Hello World program. When I run the application locally, I can navigate to http://localhost:8080/ and see the "Hello World" greeting displayed on the page. I have also created a Dockerfile and can build an image from it.

My next goal is to deploy this to a local Kubernetes cluster. I have used Docker Desktop to create a local kubernetes cluster. I want to create a deployment for my application, host it locally on the cluster, and access it from a browser.

I am not sure where to start with this deployment. I know that I will need to create charts, but I have no idea how to ultimately push this image to my cluster...

Answer 1

You need to create a kubernetes deployment and service definitions respectively.

These definitions can be in json or yaml format. Here is example definitions, you can use these definitions as template for your deploy.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: your-very-first-deployment
  labels:
    app: first-deployment
spec:
  replicas: 1
  selector:
    matchLabels:
      app: first-deployment
  template:
    metadata:
      labels:
        app: first-deployment
    spec:
      containers:
      - name: your-app
        image: your-image:with-version
        ports:
        - containerPort: 8080
---
apiVersion: v1
kind: Service
metadata:
  name: your-service
spec:
  type: NodePort
  ports:
    - port: 80
      nodePort: 30180
      targetPort: 8080
  selector:
    app: first-deployment

Do not forget to update image line in deployment yaml with your image name and image version . After that replacement, save this file with name for example deployment.yaml and then apply this definition with kubectl apply -f deployment.yml command.

Note that , you need to use port 30180 to access your application as it is stated in service definition as nodePort value. ( http://localhost:30180 )

Links :

Kubernetes services: https://kubernetes.io/docs/concepts/services-networking/service/

Kubernetes deployments: https://kubernetes.io/docs/concepts/workloads/controllers/deployment/

Answer 2

您需要先定义部署才能启动，在部署中定义docker镜像和所需的环境。