Focus on core container and orchestration workflows, hands-on troubleshooting, and real-world constraints to succeed in live build interviews.

Core Preparation Workflow

1. Master Docker Fundamentals

• Build and push images:

  docker build -t myapp:1.0 .  
  docker push myregistry/myapp:1.0  
  

• Networking: Test custom networks and service discovery:

  docker network create mynet  
  docker run --network mynet --name db postgres  
  docker run --network mynet --rm alpine nslookup db  
  

• Volumes: Mount configs and persist data:

  docker volume create app-data  
  docker run -v app-data:/app/data myapp:1.0  
  

2. Kubernetes Essentials

• Deploy and expose apps:

  kubectl apply -f deployment.yaml  
  kubectl expose deployment myapp --type=LoadBalancer  
  

• Debugging:

  kubectl describe pod myapp-1234  
  kubectl logs myapp-1234 --previous  
  kubectl get events --sort-by=.metadata.creationTimestamp  
  

• ConfigMaps/Secrets:

  kubectl create configmap app-config --from-literal=key=value  
  kubectl set envfrom deployment/myapp --configmap=app-config  
  

3. Practice Live Build Scenarios

• Multi-tier app: Deploy a frontend, backend, and DB with persistent storage.
• Troubleshoot: Simulate failures (e.g., node taints, OOM kills) and recover.
• Scale: Use HPA and VPA:

  kubectl autoscale deployment myapp --cpu-percent=50 --min=2 --max=5  
  

Tooling and Environment Setup

• Local clusters:
  • kind create cluster --name prep (fast, container-based)
  • k3d cluster create prep (supports multi-node, ingress)
• CLI tools:
  • kubectl plugins: kubectl krew install view-logs, kubectl krew install top
  • helm for templating: helm install mychart ./chart
• Visibility:
  • stern myapp for multi-pod logs
  • kubectl top node/pod for resource monitoring

Tradeoffs and Caveats

• Kind vs. Minikube:
  • Kind: Faster, lighter, but no load-balancer support by default.
  • Minikube: Slower, heavier, but better for advanced networking/storage testing.
• Helm vs. Raw Manifests:
  • Helm simplifies versioning but adds complexity. For interviews, prioritize raw YAML unless specified.
• Real-World Constraints:
  • Not all interview tasks mirror production (e.g., no RBAC or network policies). Focus on core concepts first.

Troubleshooting Common Failures

• ImagePullBackOff:
  • Verify image name/tag: kubectl describe pod → check Events.
  • Pull manually: docker pull myregistry/myapp:1.0.
• CrashLoopBackOff:
  • Check logs: kubectl logs <pod> --previous.
  • Validate liveness/readiness probes in deployment YAML.
• Service Not Reachable:
  • Test DNS: kubectl run -it --rm busybox -- nslookup myservice.
  • Check ingress rules or nodeport configuration.

Policy Example: Resource Limits

En

Source thread: How to prepare for this Docker + Kubernetes live build interview for an SDE intern role?