developer-environment-setup

Kubernetes Configuration Examples

Simple Deployment

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nodejs-app
  labels:
    app: nodejs-app
spec:
  replicas: 3
  selector:
    matchLabels:
      app: nodejs-app
  template:
    metadata:
      labels:
        app: nodejs-app
    spec:
      containers:
      - name: nodejs-app
        image: your-registry/nodejs-app:latest
        ports:
        - containerPort: 3000
        env:
        - name: NODE_ENV
          value: "production"
        - name: DATABASE_URL
          valueFrom:
            secretKeyRef:
              name: app-secrets
              key: database-url
        resources:
          requests:
            memory: "128Mi"
            cpu: "100m"
          limits:
            memory: "256Mi"
            cpu: "200m"
        livenessProbe:
          httpGet:
            path: /health
            port: 3000
          initialDelaySeconds: 30
          periodSeconds: 10
        readinessProbe:
          httpGet:
            path: /ready
            port: 3000
          initialDelaySeconds: 10
          periodSeconds: 5
---
apiVersion: v1
kind: Service
metadata:
  name: nodejs-app-service
spec:
  selector:
    app: nodejs-app
  ports:
  - protocol: TCP
    port: 80
    targetPort: 3000
  type: LoadBalancer

ConfigMap

apiVersion: v1
kind: ConfigMap
metadata:
  name: app-config
data:
  API_URL: "https://api.example.com"
  LOG_LEVEL: "info"
  MAX_CONNECTIONS: "100"

Secret

apiVersion: v1
kind: Secret
metadata:
  name: app-secrets
type: Opaque
data:
  database-url: <base64-encoded-url>
  api-key: <base64-encoded-key>

Ingress

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: app-ingress
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /
    cert-manager.io/cluster-issuer: "letsencrypt-prod"
spec:
  tls:
  - hosts:
    - example.com
    secretName: example-tls
  rules:
  - host: example.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: nodejs-app-service
            port:
              number: 80

Horizontal Pod Autoscaler

apiVersion: autoscaling/v2
kind: HorizontalPodAutoscaler
metadata:
  name: nodejs-app-hpa
spec:
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: nodejs-app
  minReplicas: 2
  maxReplicas: 10
  metrics:
  - type: Resource
    resource:
      name: cpu
      target:
        type: Utilization
        averageUtilization: 70
  - type: Resource
    resource:
      name: memory
      target:
        type: Utilization
        averageUtilization: 80

Common Commands

# Apply configuration
kubectl apply -f deployment.yaml

# Get resources
kubectl get pods
kubectl get services
kubectl get deployments

# Describe resource
kubectl describe pod <pod-name>

# View logs
kubectl logs <pod-name>
kubectl logs -f <pod-name>  # Follow logs

# Execute commands in pod
kubectl exec -it <pod-name> -- /bin/bash

# Scale deployment
kubectl scale deployment nodejs-app --replicas=5

# Delete resources
kubectl delete -f deployment.yaml
kubectl delete pod <pod-name>

# Port forwarding
kubectl port-forward service/nodejs-app-service 8080:80

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