Helm Chart Patterns

Helm Chart Patterns

Expert guidance for developing production-grade Helm charts covering chart structure, templating patterns, multi-environment configuration, dependency management, testing strategies, and distribution workflows for Kubernetes application packaging.

When to Use This Skill

• Creating reusable Helm charts for applications and services
• Building application catalogs and chart repositories
• Managing multi-environment deployments (dev, staging, production)
• Implementing advanced templating with conditionals and loops
• Managing chart dependencies and subcharts
• Implementing chart hooks for lifecycle management
• Testing and validating chart templates
• Packaging and distributing charts via repositories
• Using Helmfile for multi-chart orchestration

Core Concepts

Chart Types

• Application charts: Standard deployable charts for your services
• Library charts: Reusable template helpers (not directly installable)

Key Files

Template Essentials

• Quote strings: {{ .Values.name | quote }}
• Indent properly: {{- toYaml . | nindent 4 }}
• Use helpers: {{ include "my-app.fullname" . }}
• Check nil: {{- if .Values.optional }}

Quick Reference

Workflow

1. Structure - Set up chart directory with Chart.yaml and values.yaml
2. Template - Create Kubernetes manifests with Go templating
3. Helpers - Extract common patterns into _helpers.tpl
4. Validate - Use values.schema.json for input validation
5. Test - Lint, template, and run chart tests
6. Package - Create .tgz and publish to repository

Essential Commands

# Development
helm create my-app          # Scaffold new chart
helm lint ./my-app          # Validate chart
helm template my-app ./my-app  # Render templates

# Dependencies
helm dependency update      # Download dependencies
helm dependency list        # Show dependencies

# Testing
helm install my-app ./my-app --dry-run --debug
helm test my-app

# Distribution
helm package ./my-app
helm repo index . --url https://charts.example.com
helm push my-app-1.0.0.tgz oci://registry.example.com/charts

Common Mistakes

• Forgetting to quote strings in templates
• Not using nindent for proper YAML formatting
• Committing secrets to values files
• Missing security contexts (runAsNonRoot, drop capabilities)
• Not pinning dependency versions
• Skipping values.schema.json validation
• Not testing upgrades from previous versions

Resources

• Helm Documentation: https://helm.sh/docs/
• Chart Template Guide: https://helm.sh/docs/chart_template_guide/
• Best Practices: https://helm.sh/docs/chart_best_practices/
• Helmfile: https://github.com/helmfile/helmfile
• Chart Testing: https://github.com/helm/chart-testing