Creating Kubernetes Deployments

Prerequisites

Before using this skill, ensure:

• Kubernetes cluster is accessible and kubectl is configured
• Container image is built and pushed to registry
• Understanding of application resource requirements
• Namespace exists or will be created
• Ingress controller is installed (if using ingress)
• TLS certificates are available (if using HTTPS)

Instructions

1. Gather Requirements: Application name, image, replicas, ports, environment
2. Create Deployment: Generate YAML with container spec and resource limits
3. Add Health Checks: Configure liveness and readiness probes
4. Define Service: Create ClusterIP, NodePort, or LoadBalancer service
5. Configure Ingress: Set up routing rules and TLS termination
6. Add ConfigMaps/Secrets: Externalize configuration and sensitive data
7. Enable Auto-scaling: Create HorizontalPodAutoscaler if needed
8. Apply Manifests: Use kubectl apply to deploy resources

Output

Deployment Manifest:

# {baseDir}/k8s/deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-web-app
  namespace: production
spec:
  replicas: 3
  selector:
    matchLabels:
      app: my-web-app
  template:
    metadata:
      labels:
        app: my-web-app
    spec:
      containers:
      - name: app
        image: registry/my-web-app:v1.0.0
        ports:
        - containerPort: 80
        resources:
          requests:
            cpu: 100m
            memory: 128Mi
          limits:
            cpu: 500m
            memory: 512Mi
        livenessProbe:
          httpGet:
            path: /health
            port: 80
          initialDelaySeconds: 30
          periodSeconds: 10
        readinessProbe:
          httpGet:
            path: /ready
            port: 80
          initialDelaySeconds: 5
          periodSeconds: 5

Service and Ingress:

# {baseDir}/k8s/service.yaml
apiVersion: v1
kind: Service
metadata:
  name: my-web-app
  namespace: production
spec:
  type: ClusterIP
  selector:
    app: my-web-app
  ports:
  - port: 80
    targetPort: 80
---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: my-web-app
  namespace: production
spec:
  tls:
  - hosts:
    - app.example.com
    secretName: tls-cert
  rules:
  - host: app.example.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: my-web-app
            port:
              number: 80

Error Handling

Image Pull Error

• Error: "ErrImagePull" or "ImagePullBackOff"
• Solution: Verify image name, tag, and registry credentials in imagePullSecrets

CrashLoopBackOff

• Error: Pod repeatedly crashes and restarts
• Solution: Check application logs with kubectl logs and review container health

Resource Quota Exceeded

• Error: "forbidden: exceeded quota"
• Solution: Reduce resource requests or increase namespace quota

Ingress Not Working

• Error: 404 or 503 on ingress domain
• Solution: Verify ingress controller is running and service endpoints are ready

TLS Certificate Error

• Error: "certificate signed by unknown authority"
• Solution: Create or update TLS secret with valid certificate

Resources

• Kubernetes documentation: https://kubernetes.io/docs/
• kubectl reference: https://kubernetes.io/docs/reference/kubectl/
• Deployment best practices: https://kubernetes.io/docs/concepts/workloads/
• Example manifests in {baseDir}/k8s-examples/