Kubernetes Operations

Deploy and manage containerized applications on Kubernetes clusters.

Prerequisites

• kubectl installed and configured
• Access to a Kubernetes cluster
• Basic understanding of containers

Core Resources

Deployment

apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp
  labels:
    app: myapp
spec:
  replicas: 3
  selector:
    matchLabels:
      app: myapp
  template:
    metadata:
      labels:
        app: myapp
    spec:
      containers:
      - name: myapp
        image: myapp: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: 10
        readinessProbe:
          httpGet:
            path: /ready
            port: 8080
          initialDelaySeconds: 5
          periodSeconds: 5
        env:
        - name: DATABASE_URL
          valueFrom:
            secretKeyRef:
              name: myapp-secrets
              key: database-url

Service

apiVersion: v1
kind: Service
metadata:
  name: myapp
spec:
  selector:
    app: myapp
  ports:
  - port: 80
    targetPort: 8080
  type: ClusterIP
---
# LoadBalancer for external access
apiVersion: v1
kind: Service
metadata:
  name: myapp-external
spec:
  selector:
    app: myapp
  ports:
  - port: 80
    targetPort: 8080
  type: LoadBalancer

Ingress

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

Configuration Management

ConfigMap

apiVersion: v1
kind: ConfigMap
metadata:
  name: myapp-config
data:
  config.yaml: |
    server:
      port: 8080
    logging:
      level: info
  APP_ENV: production

# Using ConfigMap
containers:
- name: myapp
  envFrom:
  - configMapRef:
      name: myapp-config
  volumeMounts:
  - name: config
    mountPath: /etc/config
volumes:
- name: config
  configMap:
    name: myapp-config

Secret

apiVersion: v1
kind: Secret
metadata:
  name: myapp-secrets
type: Opaque
stringData:
  database-url: postgres://user:pass@host:5432/db
  api-key: secret-key-value

# Create secret from command line
kubectl create secret generic myapp-secrets \
  --from-literal=database-url='postgres://...' \
  --from-file=tls.crt=cert.pem

kubectl Commands

Resource Management

# Apply configuration
kubectl apply -f deployment.yaml

# Get resources
kubectl get pods
kubectl get deployments
kubectl get services
kubectl get all -n myapp

# Describe resource
kubectl describe pod myapp-xxx

# Delete resource
kubectl delete -f deployment.yaml
kubectl delete pod myapp-xxx

# Edit resource
kubectl edit deployment myapp

Debugging

# View logs
kubectl logs myapp-xxx
kubectl logs -f myapp-xxx --tail=100
kubectl logs myapp-xxx -c sidecar  # specific container

# Execute command
kubectl exec -it myapp-xxx -- /bin/sh

# Port forward
kubectl port-forward svc/myapp 8080:80
kubectl port-forward pod/myapp-xxx 8080:8080

# View events
kubectl get events --sort-by='.lastTimestamp'

# Debug pod
kubectl debug myapp-xxx -it --image=busybox

Scaling

# Manual scaling
kubectl scale deployment myapp --replicas=5

# Autoscaling
kubectl autoscale deployment myapp \
  --min=2 --max=10 \
  --cpu-percent=80

Horizontal Pod Autoscaler

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

Persistent Storage

PersistentVolumeClaim

apiVersion: v1
kind: PersistentVolumeClaim
metadata:

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