K8S YAML Generator

K8s Generator

Overview

This skill provides a complete workflow for generating Kubernetes YAML resources with built-in validation and intelligent CRD support. Generate production-ready manifests for any Kubernetes resource type, with automatic validation and version-aware documentation lookup for custom resources.

When to Use This Skill

Use this skill when:

• Generating Kubernetes YAML manifests (Deployments, Services, ConfigMaps, etc.)
• Creating custom resources (ArgoCD Applications, Istio VirtualServices, etc.)
• Building production-ready Kubernetes configurations
• Need to ensure YAML validity and K8s API compliance
• Working with CRDs that require documentation lookup

Core Workflow

Follow this workflow when generating Kubernetes YAML resources:

1. Understand Requirements

Gather information about:

• Resource type (Deployment, Service, ConfigMap, CRD, etc.)
• Target Kubernetes version (if specified)
• Application requirements (replicas, ports, volumes, etc.)
• Environment-specific needs (namespaces, labels, annotations)
• Custom resource specifications (for CRDs)

For CRDs specifically:

• Identify the CRD type and version (e.g., ArgoCD Application v1alpha1, Istio VirtualService v1beta1)
• Determine if documentation is needed (complex CRDs, unfamiliar APIs)

2. Fetch CRD Documentation (if needed)

When dealing with Custom Resource Definitions (CRDs):

IMPORTANT: Always consider version compatibility when working with CRDs

Step 2a: Identify the CRD and Version

• Extract the CRD's apiVersion and kind from the user request
• Examples:
  • ArgoCD Application: apiVersion: argoproj.io/v1alpha1, kind: Application
  • Istio VirtualService: apiVersion: networking.istio.io/v1beta1, kind: VirtualService
  • Cert-Manager Certificate: apiVersion: cert-manager.io/v1, kind: Certificate

Step 2b: Resolve Library ID using Context7 MCP

Use the mcp__context7__resolve-library-id tool to find the correct library:

libraryName: "<project-name>"

Examples:

• For ArgoCD: libraryName: "argo-cd"
• For Istio: libraryName: "istio"
• For Cert-Manager: libraryName: "cert-manager"

The tool will return:

• A list of matching libraries with their Context7-compatible IDs (format: /org/project or /org/project/version)
• Benchmark scores indicating documentation quality
• Code snippet counts showing coverage

Select the most appropriate library based on:

• Name match accuracy
• Target version compatibility (if user specified a version)
• Benchmark score (higher is better, 100 is highest)
• Documentation coverage (code snippet count)

Step 2c: Fetch Documentation using Context7 MCP

Use the mcp__context7__get-library-docs tool with the selected library ID:

context7CompatibleLibraryID: "/org/project/version"
topic: "specific CRD type or feature"
page: 1

Examples:

• For ArgoCD Application CRD: context7CompatibleLibraryID: "/argoproj/argo-cd/v2.9.0", topic: "application crd spec", page: 1
• For Istio VirtualService: context7CompatibleLibraryID: "/istio/istio/1.20.0", topic: "virtualservice", page: 1

If context is insufficient:

• Increment the page parameter (page: 2, page: 3, etc.) with the same topic
• Try different topic keywords
• Maximum page number is 10

Step 2d: Fallback to Web Search

If context7 MCP fails or returns insufficient information:

• Use the WebSearch tool with version-specific queries
• Include the version in the search query: "<CRD-name> <version> spec documentation"
• Examples:
  • "ArgoCD Application v1alpha1 spec documentation"
  • "Istio VirtualService v1beta1 configuration"
  • "cert-manager Certificate v1 spec fields"

CRITICAL: Always include version information in web searches to ensure compatibility

3. Generate YAML Resource

Apply Kubernetes best practices:

General Best Practices:

• Use explicit API versions (avoid deprecated versions)
• Include meaningful labels for organization and selection (use Kubernetes recommended labels):

  labels:
    app.kubernetes.io/name: myapp
    app.kubernetes.io/instance: myapp-abc123
    app.kubernetes.io/version: "1.0.0"
    app.kubernetes.io/component: frontend
    app.kubernetes.io/part-of: myplatform
    app.kubernetes.io/managed-by: claude-code
  

• Add annotations for metadata and tooling:

  annotations:
    description: "Purpose of this resource"
    contact: "team@example.com"
  

• Specify resource requests and limits (for Pods):

  resources:
    requests:
      memory: "64Mi"
      cpu: "250m"
    limits:
      memory: "128Mi"
      cpu: "500m"
  

• Use namespaces for multi-tenancy
• Implement health checks (livenessProbe, readinessProbe)
• Follow naming conventions (lowercase, hyphens, descriptive)

Security Best Practices:

• Never run containers as root (use securityContext)
• Implement Pod Security Standards
• Use least-privilege RBAC
• Store secrets in Secret objects, not ConfigMaps
• Use imagePullPolicy: Always or IfNotPresent appropriately

For CRDs:

• Reference the fetched documentation for accurate spec fields
• Include all required fields
• Use appropriate defaults for optional fields
• Add comments explaining complex configurations

Common Resource Templates:

Deployment:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp
  namespace: default
  labels:
    app.kubernetes.io/name: myapp
    app.kubernetes.io/instance: myapp-prod
    app.kubernetes.io/version: "1.0.0"
    app.kubernetes.io/component: backend
    app.kubernetes.io/part-of: myplatform
    app.kubernetes.io/managed-by: claude-code
spec:
  replicas: 3
  selector:
    matchLabels:
      app.kubernetes.io/name: myapp
      app.kubernetes.io/instance: myapp-prod
  template:
    metadata:
      labels:
        app.kubernetes.io/name: myapp
        app.kubernetes.io/instance: myapp-prod
        app.kubernetes.io/version: "1.0.0"
        app.kubernetes.io/component: backend
        app.kubernetes.io/part-of: myplatform
        app.kubernetes.io/managed-by: claude-code
    spec:
      containers:
      - name: myapp
        image: myapp:1.0.0
        ports:
        - containerPort: 8080
        resources:
          requests:
            memory: "64Mi"
            cpu: "250m"
          limits:
            memory: "128Mi"
            cpu: "500m"
        livenessProbe:
          httpGet:
            path: /health
            port: 8080
          initialDelaySeconds: 30
          periodSeconds: 10
        readinessProbe:
          httpGet:
            path: /ready
            port: 8080
          initialDelaySeconds: 5
          periodSeconds: 5

Service:

apiVersion: v1
kind: Service
metadata:
  name: myapp-service
  namespace: default
  labels:
    app.kubernetes.io/name: myapp
    app.kubernetes.io/instance: myapp-prod
    app.kubernetes.io/component: backend
    app.kubernetes.io/part-of: myplatform
    app.kubernetes.io/managed-by: claude-code
spec:
  type: ClusterIP  # or LoadBalancer, NodePort
  selector:
    app.kubernetes.io/name: myapp
    app.kubernetes.io/instance: myapp-prod
  ports:
  - protocol: TCP
    port: 80
    targetPort: 8080
    name: http

ConfigMap:

apiVersion: v1
kind: ConfigMap
metadata:
  name: myapp-config
  namespace: default
  labels:
    app.kubernetes.io/name: myapp
    app.kubernetes.io/instance: myapp-prod
    app.kubernetes.io/component: config
    app.kubernetes.io/part-of: myplatform
    app.kubernetes.io/managed-by: claude-code
data:
  app.properties: |
    key1=value1
    key2=value2
  config.json: |
    {
      "setting": "value"
    }

4. Validate Generated YAML

CRITICAL: Always validate generated YAML using the devops-skills:k8s-yaml-validator skill

After generating the YAML resource, immediately invoke the devops-skills:k8s-yaml-validator skill:

Use the Skill tool:

Skill: devops-skills:k8s-yaml-validator

The devops-skills:k8s-yaml-validator skill will:

1. Validate YAML syntax using yamllint
2. Validate Kubernetes API compliance using kubeconform
3. Check for best practices and common issues
4. For CRDs: Automatically detect custom resources and fetch documentation if needed
5. Perform dry-run validation against the cluster (if available)

Wait for validation results and address any issues:

• Syntax errors: Fix YAML formatting issues
• Schema errors: Correct field names, types, or structure
• Best practice violations: Update according to recommendations
• CRD validation errors: Re-fetch documentation and correct spec fields

If validation fails:

• Review the error messages carefully
• Update the YAML to address the issues
• Re-run validation
• Repeat until validation passes

5. Deliver the Resource

Once validation passes:

• Present the validated YAML to the user
• Include a summary of what was generated
• Highlight any important configuration choices
• Suggest next steps (kubectl apply, customization, etc.)

Format:

# Generated and validated Kubernetes resource
# Resource: <Type>
# Namespace: <namespace>
# Validation: Passed

<YAML content here>

Suggest next steps:

# Apply the resource
kubectl apply -f <filename>.yaml

# Verify the resource
kubectl get <resource-type> <name> -n <namespace>

# Check status
kubectl describe <resource-type> <name> -n <namespace>

Advanced Features

Multi-Resource Generation

When generating multiple related resources:

1. Create each resource following the core workflow
2. Use consistent labels across resources for grouping
3. Consider resource dependencies (create ConfigMaps before Deployments)
4. Validate each resource individually with devops-skills:k8s-yaml-validator
5. Optionally combine into a single multi-document YAML file using --- separator

Example multi-document YAML:

apiVersion: v1
kind: ConfigMap
metadata:
  name: myapp-config
  labels:
    app.kubernetes.io/name: myapp
    app.kubernetes.io/instance: myapp-prod
    app.kubernetes.io/part-of: myplatform
data:
  key: value
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp
  labels:
    app.kubernetes.io/name: myapp
    app.kubernetes.io/instance: myapp-prod
    app.kubernetes.io/part-of: myplatform
spec:
  # deployment spec with matching labels
---
apiVersion: v1
kind: Service
metadata:
  name: myapp-service
  labels:
    app.kubernetes.io/name: myapp
    app.kubernetes.io/instance: myapp-prod
    app.kubernetes.io/part-of: myplatform
spec:
  # service spec with matching selector

Version-Specific Generation

When targeting specific Kubernetes versions:

• Use appropriate API versions (check deprecations)
• Reference version-specific features
• Note any version-specific caveats
• Example: Ingress moved from extensions/v1beta1 to networking.k8s.io/v1 in K8s 1.19+

Namespace Management

Best practices for namespace handling:

• Always specify namespace in metadata (except for cluster-scoped resources)
• Use namespaces for environment separation (dev, staging, prod)
• Consider namespace-scoped resources vs cluster-scoped
• Include namespace creation YAML if needed

Common CRDs and Examples

ArgoCD Application

apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: myapp
  namespace: argocd
  labels:
    app.kubernetes.io/name: myapp
    app.kubernetes.io/instance: myapp-prod
    app.kubernetes.io/part-of: myplatform
    app.kubernetes.io/managed-by: argocd
spec:
  project: default
  source:
    repoURL: https://github.com/org/repo
    targetRevision: HEAD
    path: manifests
  destination:
    server: https://kubernetes.default.svc
    namespace: myapp
  syncPolicy:
    automated:
      prune: true
      selfHeal: true

Istio VirtualService

apiVersion: networking.istio.io/v1beta1
kind: VirtualService
metadata:
  name: myapp
  labels:
    app.kubernetes.io/name: myapp
    app.kubernetes.io/instance: myapp-prod
    app.kubernetes.io/component: networking
    app.kubernetes.io/part-of: myplatform
spec:
  hosts:
  - myapp.example.com
  gateways:
  - myapp-gateway
  http:
  - route:
    - destination:
        host: myapp-service
        port:
          number: 8080

Cert-Manager Certificate

apiVersion: cert-manager.io/v1
kind: Certificate
metadata:
  name: myapp-tls
  namespace: default
  labels:
    app.kubernetes.io/name: myapp
    app.kubernetes.io/instance: myapp-prod
    app.kubernetes.io/component: tls
    app.kubernetes.io/part-of: myplatform
spec:
  secretName: myapp-tls-secret
  issuerRef:
    name: letsencrypt-prod
    kind: ClusterIssuer
  dnsNames:
  - myapp.example.com

Troubleshooting

CRD Documentation Not Found

• Issue: Context7 MCP cannot find the CRD documentation
• Solution:
  • Try alternative search terms (project name variations)
  • Use WebSearch as fallback with version-specific queries
  • Check the official project documentation directly

Validation Failures

• Issue: devops-skills:k8s-yaml-validator reports errors
• Solution:
  • Read error messages carefully
  • Check field names and types against documentation
  • Verify API version compatibility
  • Ensure required fields are present

Version Mismatches

• Issue: Generated YAML uses wrong API version
• Solution:
  • Confirm target Kubernetes version with user
  • Check API deprecation status
  • Update apiVersion field to correct version
  • Re-validate

Integration with Other Skills

This skill works seamlessly with:

• devops-skills:k8s-yaml-validator: Automatic validation of generated resources
• k8s-debug: Troubleshooting deployed resources
• helm-validator: Validating Helm charts that use these resources

Summary

The k8s-generator skill provides:

1. ✅ Intelligent YAML generation for any Kubernetes resource
2. ✅ Automatic validation via devops-skills:k8s-yaml-validator
3. ✅ Version-aware CRD documentation lookup via context7 MCP
4. ✅ Fallback web search for CRD specifications
5. ✅ Best practices and security considerations
6. ✅ Production-ready configurations

Always follow the core workflow: Understand → Fetch CRD Docs (if needed) → Generate → Validate → Deliver