Kubernetes Deployments & Services

Deployments und Services sind das Herzstück von Kubernetes. Lernen Sie, wie Sie Anwendungen zuverlässig deployen und erreichbar machen.

Deployment erstellen

# deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-app
  labels:
    app: my-app
spec:
  replicas: 3
  selector:
    matchLabels:
      app: my-app
  template:
    metadata:
      labels:
        app: my-app
    spec:
      containers:
      - name: my-app
        image: my-app:1.0.0
        ports:
        - containerPort: 8080
        resources:
          requests:
            memory: "128Mi"
            cpu: "100m"
          limits:
            memory: "256Mi"
            cpu: "500m"
        livenessProbe:
          httpGet:
            path: /health
            port: 8080
          initialDelaySeconds: 10
          periodSeconds: 5
        readinessProbe:
          httpGet:
            path: /ready
            port: 8080
          initialDelaySeconds: 5
          periodSeconds: 3

Deployment anwenden

# Deployment erstellen
kubectl apply -f deployment.yaml

# Status prüfen
kubectl get deployments
kubectl get pods

# Details anzeigen
kubectl describe deployment my-app

# Logs eines Pods
kubectl logs -f deployment/my-app

# In Pod einloggen
kubectl exec -it deployment/my-app -- /bin/sh

Service-Typen

Service erstellen

# service.yaml
apiVersion: v1
kind: Service
metadata:
  name: my-app-service
spec:
  selector:
    app: my-app
  ports:
  - port: 80          # Service-Port
    targetPort: 8080  # Container-Port
  type: ClusterIP

# NodePort Service
apiVersion: v1
kind: Service
metadata:
  name: my-app-nodeport
spec:
  selector:
    app: my-app
  ports:
  - port: 80
    targetPort: 8080
    nodePort: 30080   # 30000-32767
  type: NodePort

# LoadBalancer Service
apiVersion: v1
kind: Service
metadata:
  name: my-app-lb
spec:
  selector:
    app: my-app
  ports:
  - port: 80
    targetPort: 8080
  type: LoadBalancer

Service-Befehle

# Service erstellen
kubectl apply -f service.yaml

# Services anzeigen
kubectl get services

# Service-Details
kubectl describe service my-app-service

# Service testen (von einem Pod aus)
kubectl run test --rm -it --image=busybox -- wget -qO- my-app-service:80

Scaling

# Manuell skalieren
kubectl scale deployment my-app --replicas=5

# Autoscaling (HPA)
kubectl autoscale deployment my-app --min=2 --max=10 --cpu-percent=80

# HPA Status
kubectl get hpa

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

Rolling Updates

# Update-Strategie im Deployment
spec:
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 1        # Max zusätzliche Pods
      maxUnavailable: 0  # Immer alle verfügbar

# Image updaten
kubectl set image deployment/my-app my-app=my-app:2.0.0

# Rollout-Status
kubectl rollout status deployment/my-app

# Rollout-History
kubectl rollout history deployment/my-app

# Rollback
kubectl rollout undo deployment/my-app
kubectl rollout undo deployment/my-app --to-revision=2

ConfigMaps und Secrets

# ConfigMap
apiVersion: v1
kind: ConfigMap
metadata:
  name: my-config
data:
  DATABASE_HOST: "postgres"
  LOG_LEVEL: "info"
  config.json: |
    {
      "setting": "value"
    }

# Secret
apiVersion: v1
kind: Secret
metadata:
  name: my-secrets
type: Opaque
data:
  DB_PASSWORD: cGFzc3dvcmQxMjM=  # base64

# Im Deployment verwenden
spec:
  containers:
  - name: my-app
    envFrom:
    - configMapRef:
        name: my-config
    - secretRef:
        name: my-secrets
    volumeMounts:
    - name: config-volume
      mountPath: /app/config
  volumes:
  - name: config-volume
    configMap:
      name: my-config

Ingress (HTTP Routing)

# ingress.yaml
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: my-ingress
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /
spec:
  ingressClassName: nginx
  rules:
  - host: myapp.example.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: my-app-service
            port:
              number: 80
  tls:
  - hosts:
    - myapp.example.com
    secretName: myapp-tls

Weitere Informationen

• ☸️ Kubernetes Grundlagen
• 🐳 Docker Multi-Stage Builds
• 📊 Enjyn Status Monitor