Kustomize Practice Questions (Compressed)

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Question 1 – Multi-Environment Base + Overlays with Patches

Task: Build a complete base application with dev/prod overlays using patches and ConfigMap generators. This is a dependent question—your solution here becomes the foundation for Q2 and Q3.

Steps:

1. Create base structure:

   base/
     deployment.yaml       # API server: node:18-alpine, port 3000, 1 replica
     service.yaml          # ClusterIP service on port 80→3000
     configmap.yaml        # APP_NAME, LOG_LEVEL, REDIS_HOST
     redis-deployment.yaml # Redis: redis:7-alpine, port 6379
     redis-service.yaml    # Redis ClusterIP service
     kustomization.yaml    # resources: [all above]

2. Create dev overlay with patches:

   overlays/dev/
     kustomization.yaml    # resources: ../../base, namespace: dev, namePrefix: dev-, patches: [deployment-patch.yaml]
     patches/
       deployment-patch.yaml    # Patch replicas: 2

3. Create prod overlay with patches + resource limits:

   overlays/prod/
     kustomization.yaml    # resources: ../../base, namespace: prod, namePrefix: prod-, patches: [deployment-patch.yaml, resources-patch.yaml]
     patches/
       deployment-patch.yaml    # Patch replicas: 4
       resources-patch.yaml     # CPU: 100m→500m, Memory: 128Mi→512Mi

4. Add labels to both overlays using labels field (no deprecation warnings)

5. Test:

   kustomize build overlays/dev/
   kustomize build overlays/prod/

Deliverables:

• ✅ Base with 5 resources (2 deployments, 2 services, 1 configmap)
• ✅ Dev overlay: 2 replicas, dev namespace, dev- prefix, labels applied
• ✅ Prod overlay: 4 replicas, prod namespace, prod- prefix, resource limits, labels applied
• ✅ Both build cleanly with no warnings

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Question 2 – ConfigMap/Secret Generators + Image Patching (Dependent on Q1)

Task: Extend your Q1 solution to replace static ConfigMaps with generators and manage image tags per environment.

Steps:

1. Create environment config files:

   overlays/dev/.env.config      # APP_NAME=myapp-dev, LOG_LEVEL=debug, REDIS_HOST=redis-service
   overlays/prod/.env.config     # APP_NAME=myapp-prod, LOG_LEVEL=info, REDIS_HOST=redis-service

2. Create secret files:

   overlays/dev/.env.secrets     # DB_PASSWORD=devpass123, DB_USER=dev
   overlays/prod/.env.secrets    # DB_PASSWORD=prod-secure-xyz, DB_USER=prod

3. Update overlays/dev/kustomization.yaml:

   • Add configMapGenerator: with .env.config file
   • Add secretGenerator: with .env.secrets file
   • Add images: section: change node tag to 18-alpine
   • Update deployment to reference generated ConfigMap name (with hash)

4. Update overlays/prod/kustomization.yaml:

   • Same generators as dev (but different .env files)
   • images: change node tag to 18.20.0-alpine
   • Add kustomization flag to not add hash suffix (optional, for stable names)

5. Test:

   kustomize build overlays/dev/ | grep ConfigMap
   kustomize build overlays/prod/ | grep ConfigMap
   kustomize build overlays/dev/ | grep image:
   kustomize build overlays/prod/ | grep image:

Deliverables:

• ✅ ConfigMaps generated from files (show hash suffix)
• ✅ Secrets generated from files
• ✅ Image tags differ: dev uses 18-alpine, prod uses 18.20.0-alpine
• ✅ Deployment references generated ConfigMap correctly
• ✅ Both build successfully

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Question 3 – Advanced: Composable Multi-Base + JSON Patches (Independent)

Task: Build a separate advanced project that demonstrates multi-base composition, JSON patches (RFC 6902), and cross-cutting concerns (monitoring, security policies).

Steps:

1. Create separate project structure:

   advanced/
     bases/
       core/
         deployment.yaml    # Generic stateless app (no image hardcoded)
         service.yaml
         kustomization.yaml
       monitoring/
         servicemonitor.yaml (Prometheus)
         kustomization.yaml
       security/
         networkpolicy.yaml
         podsecuritypolicy.yaml
         kustomization.yaml
     overlays/
       staging/
         kustomization.yaml  # bases: [../../bases/core, ../../bases/monitoring], patches: [security-patch.json]
       prod/
         kustomization.yaml  # bases: [../../bases/core, ../../bases/monitoring, ../../bases/security]

2. Create JSON patches for staging (RFC 6902):

   • Add annotation monitoring: "true" to all Pods
   • Add label env: staging to Deployments
   • Patch service type to LoadBalancer (optional, for staging only)

3. Use patchesJson6902 in overlays/staging/kustomization.yaml to apply JSON patches

4. Prod overlay combines all bases directly (no JSON patches needed)

5. Test:

   kustomize build overlays/staging/ | grep annotation
   kustomize build overlays/prod/ | grep NetworkPolicy

Deliverables:

• ✅ Multi-base composition working (core + monitoring + security)
• ✅ Staging applies JSON patches correctly
• ✅ Prod includes all security bases
• ✅ Both build without errors
• ✅ Clear separation of concerns: core app / monitoring / security

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How to Approach:

1. Q1 (Foundation): Build everything from scratch. Learn base → overlay → patches workflow.
2. Q2 (Extend Q1): Use your Q1 solution as base. Add generators and image management.
3. Q3 (Standalone Deep Dive): Start fresh. Focus on advanced patterns: multi-base, JSON patches, composition.

Time estimate: Q1: 30min, Q2: 20min (extending Q1), Q3: 25min (independent exploration)