container-orchestration

name	Container Orchestration
description	Design Kubernetes deployment patterns, configure service mesh, and implement container best practices
category	devops
required_tools	["Read","Write","Bash"]

Container Orchestration

Purpose

Design and manage containerized applications using Kubernetes and container orchestration platforms, implementing deployment patterns, scaling strategies, and service management.

When to Use

• Deploying containerized applications
• Managing microservices architectures
• Implementing auto-scaling
• Configuring service discovery and load balancing
• Managing application secrets and configs
• Setting up multi-environment deployments

Key Capabilities

1. Kubernetes Deployment - Design and implement K8s resources (Deployments, Services, Ingress)
2. Scaling Strategies - Implement horizontal pod autoscaling and cluster autoscaling
3. Service Management - Configure service discovery, load balancing, and networking

Approach

1. Design Container Strategy

   • Determine container boundaries (one process per container)
   • Define resource limits (CPU, memory)
   • Plan persistent storage needs
   • Design health check endpoints

2. Create Kubernetes Manifests

   • Deployments for stateless apps
   • StatefulSets for stateful apps
   • Services for networking
   • ConfigMaps and Secrets for configuration
   • Ingress for external access

3. Implement Scaling

   • Horizontal Pod Autoscaler (HPA) based on CPU/memory/custom metrics
   • Vertical Pod Autoscaler (VPA) for resource optimization
   • Cluster Autoscaler for node scaling

4. Configure Networking

   • Service types (ClusterIP, NodePort, LoadBalancer)
   • Ingress controllers (nginx, traefik)
   • Network policies for security
   • Service mesh (Istio, Linkerd) for advanced routing

5. Manage Configuration

   • ConfigMaps for non-sensitive config
   • Secrets for sensitive data
   • External secrets operators for vault integration
   • Environment-specific configurations

Example

Context: Deploying a web application with database on Kubernetes

Deployment Manifest:

# web-deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: web-app
  labels:
    app: web
spec:
  replicas: 3
  selector:
    matchLabels:
      app: web
  template:
    metadata:
      labels:
        app: web
    spec:
      containers:
      - name: web
        image: myapp:v1.2.3
        ports:
        - containerPort: 8080
        env:
        - name: DATABASE_URL
          valueFrom:
            secretKeyRef:
              name: db-credentials
              key: url
        - name: REDIS_HOST
          valueFrom:
            configMapKeyRef:
              name: app-config
              key: redis-host
        resources:
          requests:
            memory: "256Mi"
            cpu: "250m"
          limits:
            memory: "512Mi"
            cpu: "500m"
        livenessProbe:
          httpGet:
            path: /health
            port: 8080
          initialDelaySeconds: 30
          periodSeconds: 10
        readinessProbe:
          httpGet:
            path: /ready
            port: 8080
          initialDelaySeconds: 5
          periodSeconds: 5
---
# web-service.yaml
apiVersion: v1
kind: Service
metadata:
  name: web-service
spec:
  selector:
    app: web
  ports:
  - protocol: TCP
    port: 80
    targetPort: 8080
  type: LoadBalancer
---
# web-hpa.yaml
apiVersion: autoscaling/v2
kind: HorizontalPodAutoscaler
metadata:
  name: web-hpa
spec:
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: web-app
  minReplicas: 3
  maxReplicas: 10
  metrics:
  - type: Resource
    resource:
      name: cpu
      target:
        type: Utilization
        averageUtilization: 70
  - type: Resource
    resource:
      name: memory
      target:
        type: Utilization
        averageUtilization: 80
---
# ingress.yaml
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: web-ingress
  annotations:
    cert-manager.io/cluster-issuer: "letsencrypt-prod"
    nginx.ingress.kubernetes.io/rate-limit: "100"
spec:
  tls:
  - hosts:
    - myapp.example.com
    secretName: web-tls
  rules:
  - host: myapp.example.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: web-service
            port:
              number: 80

ConfigMap:

apiVersion: v1
kind: ConfigMap
metadata:
  name: app-config
data:
  redis-host: "redis.default.svc.cluster.local"
  log-level: "info"
  feature-flag-new-ui: "true"

Secret (created via kubectl):

kubectl create secret generic db-credentials \
  --from-literal=url='postgresql://user:pass@db:5432/mydb'

Deploy:

# Apply all manifests
kubectl apply -f web-deployment.yaml

# Verify deployment
kubectl get deployments
kubectl get pods
kubectl get services
kubectl get hpa

# Check logs
kubectl logs -f deployment/web-app

# Scale manually if needed
kubectl scale deployment web-app --replicas=5

Expected Result:

• 3 replicas running initially
• Auto-scales between 3-10 based on CPU/memory
• External access via LoadBalancer or Ingress
• Health checks ensure only healthy pods receive traffic
• Zero-downtime rolling updates
• Configuration managed via ConfigMaps/Secrets

Best Practices

• ✅ Always set resource requests and limits
• ✅ Implement health checks (liveness and readiness probes)
• ✅ Use namespaces to organize resources
• ✅ Tag images with specific versions, not :latest
• ✅ Use ConfigMaps/Secrets for configuration
• ✅ Implement network policies for security
• ✅ Use StatefulSets for stateful applications
• ✅ Enable Pod Security Standards
• ✅ Implement rolling update strategies
• ✅ Monitor resource usage with metrics server
• ✅ Use init containers for setup tasks
• ✅ Implement pod disruption budgets for high availability
• ❌ Avoid: Running containers as root
• ❌ Avoid: Hardcoding configuration in images
• ❌ Avoid: Using :latest tag in production
• ❌ Avoid: No resource limits (can starve other pods)
• ❌ Avoid: Storing secrets in ConfigMaps
• ❌ Avoid: Single replica for critical services