How to Deploy an Application on K3s

Overview

Once K3s is running on your Breeze, deploying an application involves creating Kubernetes manifests for your Deployment and Service, then applying them with kubectl.

Step 1: Create a Deployment Manifest

Create a file called app-deployment.yaml:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: web-app
  namespace: default
spec:
  replicas: 2
  selector:
    matchLabels:
      app: web-app
  template:
    metadata:
      labels:
        app: web-app
    spec:
      containers:
        - name: web
          image: nginx:alpine
          ports:
            - containerPort: 80
          resources:
            requests:
              memory: "64Mi"
              cpu: "100m"
            limits:
              memory: "128Mi"
              cpu: "250m"

Step 2: Create a Service

Create app-service.yaml:

apiVersion: v1
kind: Service
metadata:
  name: web-app-svc
spec:
  selector:
    app: web-app
  ports:
    - port: 80
      targetPort: 80
  type: NodePort

Step 3: Apply and Verify

kubectl apply -f app-deployment.yaml
kubectl apply -f app-service.yaml
kubectl get pods -l app=web-app
kubectl get svc web-app-svc

Step 4: Access the Application

Find the assigned NodePort:

kubectl get svc web-app-svc -o jsonpath='{.spec.ports[0].nodePort}'

Visit http://your-breeze-ip:NODE_PORT in your browser.

Updating the Application

kubectl set image deployment/web-app web=nginx:1.25-alpine
kubectl rollout status deployment/web-app

K3s handles rolling updates automatically with zero downtime.