Helm Chart Scaffolding

Comprehensive guidance for creating, organizing, and managing Helm charts for packaging and deploying Kubernetes applications.

Purpose

This skill provides step-by-step instructions for building production-ready Helm charts, including chart structure, templating patterns, values management, and validation strategies.

When to Use This Skill

Use this skill when you need to:

Create new Helm charts from scratch
Package Kubernetes applications for distribution
Manage multi-environment deployments with Helm
Implement templating for reusable Kubernetes manifests
Set up Helm chart repositories
Follow Helm best practices and conventions

Helm Overview

Helm is the package manager for Kubernetes that:

Templates Kubernetes manifests for reusability
Manages application releases and rollbacks
Handles dependencies between charts
Provides version control for deployments
Simplifies configuration management across environments

Step-by-Step Workflow

1. Initialize Chart Structure

Create new chart:

bash

helm create my-app

Standard chart structure:

my-app/
├── Chart.yaml           # Chart metadata
├── values.yaml          # Default configuration values
├── charts/              # Chart dependencies
├── templates/           # Kubernetes manifest templates
│   ├── NOTES.txt       # Post-install notes
│   ├── _helpers.tpl    # Template helpers
│   ├── deployment.yaml
│   ├── service.yaml
│   ├── ingress.yaml
│   ├── serviceaccount.yaml
│   ├── hpa.yaml
│   └── tests/
│       └── test-connection.yaml
└── .helmignore         # Files to ignore

2. Configure Chart.yaml

Chart metadata defines the package:

yaml

apiVersion: v2
name: my-app
description: A Helm chart for My Application
type: application
version: 1.0.0 # Chart version
appVersion: "2.1.0" # Application version

# Keywords for chart discovery
keywords:
  - web
  - api
  - backend

# Maintainer information
maintainers:
  - name: DevOps Team
    email: devops@example.com
    url: https://github.com/example/my-app

# Source code repository
sources:
  - https://github.com/example/my-app

# Homepage
home: https://example.com

# Chart icon
icon: https://example.com/icon.png

# Dependencies
dependencies:
  - name: postgresql
    version: "12.0.0"
    repository: "https://charts.bitnami.com/bitnami"
    condition: postgresql.enabled
  - name: redis
    version: "17.0.0"
    repository: "https://charts.bitnami.com/bitnami"
    condition: redis.enabled

Reference: See

assets/Chart.yaml.template

for complete example

3. Design values.yaml Structure

Organize values hierarchically:

yaml

# Image configuration
image:
  repository: myapp
  tag: "1.0.0"
  pullPolicy: IfNotPresent

# Number of replicas
replicaCount: 3

# Service configuration
service:
  type: ClusterIP
  port: 80
  targetPort: 8080

# Ingress configuration
ingress:
  enabled: false
  className: nginx
  hosts:
    - host: app.example.com
      paths:
        - path: /
          pathType: Prefix

# Resources
resources:
  requests:
    memory: "256Mi"
    cpu: "250m"
  limits:
    memory: "512Mi"
    cpu: "500m"

# Autoscaling
autoscaling:
  enabled: false
  minReplicas: 2
  maxReplicas: 10
  targetCPUUtilizationPercentage: 80

# Environment variables
env:
  - name: LOG_LEVEL
    value: "info"

# ConfigMap data
configMap:
  data:
    APP_MODE: production

# Dependencies
postgresql:
  enabled: true
  auth:
    database: myapp
    username: myapp

redis:
  enabled: false

Reference: See

assets/values.yaml.template

for complete structure

4. Create Template Files

Use Go templating with Helm functions:

templates/deployment.yaml:

yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: {{ include "my-app.fullname" . }}
  labels:
    {{- include "my-app.labels" . | nindent 4 }}
spec:
  {{- if not .Values.autoscaling.enabled }}
  replicas: {{ .Values.replicaCount }}
  {{- end }}
  selector:
    matchLabels:
      {{- include "my-app.selectorLabels" . | nindent 6 }}
  template:
    metadata:
      labels:
        {{- include "my-app.selectorLabels" . | nindent 8 }}
    spec:
      containers:
      - name: {{ .Chart.Name }}
        image: "{{ .Values.image.repository }}:{{ .Values.image.tag | default .Chart.AppVersion }}"
        imagePullPolicy: {{ .Values.image.pullPolicy }}
        ports:
        - name: http
          containerPort: {{ .Values.service.targetPort }}
        resources:
          {{- toYaml .Values.resources | nindent 12 }}
        env:
          {{- toYaml .Values.env | nindent 12 }}

5. Create Template Helpers

templates/_helpers.tpl:

yaml

{{/*
Expand the name of the chart.
*/}}
{{- define "my-app.name" -}}
{{- default .Chart.Name .Values.nameOverride | trunc 63 | trimSuffix "-" }}
{{- end }}

{{/*
Create a default fully qualified app name.
*/}}
{{- define "my-app.fullname" -}}
{{- if .Values.fullnameOverride }}
{{- .Values.fullnameOverride | trunc 63 | trimSuffix "-" }}
{{- else }}
{{- $name := default .Chart.Name .Values.nameOverride }}
{{- if contains $name .Release.Name }}
{{- .Release.Name | trunc 63 | trimSuffix "-" }}
{{- else }}
{{- printf "%s-%s" .Release.Name $name | trunc 63 | trimSuffix "-" }}
{{- end }}
{{- end }}
{{- end }}

{{/*
Common labels
*/}}
{{- define "my-app.labels" -}}
helm.sh/chart: {{ include "my-app.chart" . }}
{{ include "my-app.selectorLabels" . }}
{{- if .Chart.AppVersion }}
app.kubernetes.io/version: {{ .Chart.AppVersion | quote }}
{{- end }}
app.kubernetes.io/managed-by: {{ .Release.Service }}
{{- end }}

{{/*
Selector labels
*/}}
{{- define "my-app.selectorLabels" -}}
app.kubernetes.io/name: {{ include "my-app.name" . }}
app.kubernetes.io/instance: {{ .Release.Name }}
{{- end }}

6. Manage Dependencies

Add dependencies in Chart.yaml:

yaml

dependencies:
  - name: postgresql
    version: "12.0.0"
    repository: "https://charts.bitnami.com/bitnami"
    condition: postgresql.enabled

Update dependencies:

bash

helm dependency update
helm dependency build

Override dependency values:

yaml

# values.yaml
postgresql:
  enabled: true
  auth:
    database: myapp
    username: myapp
    password: changeme
  primary:
    persistence:
      enabled: true
      size: 10Gi

7. Test and Validate

Validation commands:

bash

# Lint the chart
helm lint my-app/

# Dry-run installation
helm install my-app ./my-app --dry-run --debug

# Template rendering
helm template my-app ./my-app

# Template with values
helm template my-app ./my-app -f values-prod.yaml

# Show computed values
helm show values ./my-app

Validation script:

bash

#!/bin/bash
set -e

echo "Linting chart..."
helm lint .

echo "Testing template rendering..."
helm template test-release . --dry-run

echo "Checking for required values..."
helm template test-release . --validate

echo "All validations passed!"

Reference: See

scripts/validate-chart.sh

8. Package and Distribute

Package the chart:

bash

helm package my-app/
# Creates: my-app-1.0.0.tgz

Create chart repository:

bash

# Create index
helm repo index .

# Upload to repository
# AWS S3 example
aws s3 sync . s3://my-helm-charts/ --exclude "*" --include "*.tgz" --include "index.yaml"

Use the chart:

bash

helm repo add my-repo https://charts.example.com
helm repo update
helm install my-app my-repo/my-app

9. Multi-Environment Configuration

Environment-specific values files:

my-app/
├── values.yaml          # Defaults
├── values-dev.yaml      # Development
├── values-staging.yaml  # Staging
└── values-prod.yaml     # Production

values-prod.yaml:

yaml

replicaCount: 5

image:
  tag: "2.1.0"

resources:
  requests:
    memory: "512Mi"
    cpu: "500m"
  limits:
    memory: "1Gi"
    cpu: "1000m"

autoscaling:
  enabled: true
  minReplicas: 3
  maxReplicas: 20

ingress:
  enabled: true
  hosts:
    - host: app.example.com
      paths:
        - path: /
          pathType: Prefix

postgresql:
  enabled: true
  primary:
    persistence:
      size: 100Gi

Install with environment:

bash

helm install my-app ./my-app -f values-prod.yaml --namespace production

10. Implement Hooks and Tests

Pre-install hook:

yaml

# templates/pre-install-job.yaml
apiVersion: batch/v1
kind: Job
metadata:
  name: {{ include "my-app.fullname" . }}-db-setup
  annotations:
    "helm.sh/hook": pre-install
    "helm.sh/hook-weight": "-5"
    "helm.sh/hook-delete-policy": hook-succeeded
spec:
  template:
    spec:
      containers:
      - name: db-setup
        image: postgres:15
        command: ["psql", "-c", "CREATE DATABASE myapp"]
      restartPolicy: Never

Test connection:

yaml

# templates/tests/test-connection.yaml
apiVersion: v1
kind: Pod
metadata:
  name: "{{ include "my-app.fullname" . }}-test-connection"
  annotations:
    "helm.sh/hook": test
spec:
  containers:
  - name: wget
    image: busybox
    command: ['wget']
    args: ['{{ include "my-app.fullname" . }}:{{ .Values.service.port }}']
  restartPolicy: Never

Run tests:

bash

helm test my-app

Common Patterns

Pattern 1: Conditional Resources

yaml

{{- if .Values.ingress.enabled }}
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: {{ include "my-app.fullname" . }}
spec:
  # ...
{{- end }}

Pattern 2: Iterating Over Lists

yaml

env:
{{- range .Values.env }}
- name: {{ .name }}
  value: {{ .value | quote }}
{{- end }}

Pattern 3: Including Files

yaml

data:
  config.yaml: |
    {{- .Files.Get "config/application.yaml" | nindent 4 }}

Pattern 4: Global Values

yaml

global:
  imageRegistry: docker.io
  imagePullSecrets:
    - name: regcred

# Use in templates:
image: {{ .Values.global.imageRegistry }}/{{ .Values.image.repository }}

Best Practices

Use semantic versioning for chart and app versions
Document all values in values.yaml with comments
Use template helpers for repeated logic
Validate charts before packaging
Pin dependency versions explicitly
Use conditions for optional resources
Follow naming conventions (lowercase, hyphens)
Include NOTES.txt with usage instructions
Add labels consistently using helpers
Test installations in all environments

Troubleshooting

Template rendering errors:

bash

helm template my-app ./my-app --debug

Dependency issues:

bash

helm dependency update
helm dependency list

Installation failures:

bash

helm install my-app ./my-app --dry-run --debug
kubectl get events --sort-by='.lastTimestamp'

Reference Files

```
assets/Chart.yaml.template
```
- Chart metadata template
```
assets/values.yaml.template
```
- Values structure template
```
scripts/validate-chart.sh
```
- Validation script
```
references/chart-structure.md
```
- Detailed chart organization

Related Skills

```
k8s-manifest-generator
```
- For creating base Kubernetes manifests
```
gitops-workflow
```
- For automated Helm chart deployments

helm-chart-scaffolding

NPX Install

Tags

SKILL.md Content

Helm Chart Scaffolding

Purpose

When to Use This Skill

Helm Overview

Step-by-Step Workflow

1. Initialize Chart Structure

2. Configure Chart.yaml

3. Design values.yaml Structure

4. Create Template Files

5. Create Template Helpers

6. Manage Dependencies

7. Test and Validate

8. Package and Distribute

9. Multi-Environment Configuration

10. Implement Hooks and Tests

Common Patterns

Pattern 1: Conditional Resources

Pattern 2: Iterating Over Lists

Pattern 3: Including Files

Pattern 4: Global Values

Best Practices

Troubleshooting

Reference Files

Related Skills