---

name: helm-charts description: Use when creating Helm charts, packaging Kubernetes applications, managing multi-environment deployments, or asking about "Helm", "Helm chart", "values.yaml", "chart templating", "Helm dependencies" version: 1.0.0

Helm Chart Development

Create, organize, and manage Helm charts for Kubernetes applications.

Chart Structure

Copymy-app/
├── Chart.yaml           # Chart metadata
├── values.yaml          # Default values
├── charts/              # Dependencies
├── templates/
│   ├── NOTES.txt        # Post-install notes
│   ├── _helpers.tpl     # Template helpers
│   ├── deployment.yaml
│   ├── service.yaml
│   └── ingress.yaml
└── .helmignore

Chart.yaml

CopyapiVersion: v2
name: my-app
description: A Helm chart for My Application
version: 1.0.0
appVersion: "2.1.0"

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

values.yaml Structure

Copyimage:
  repository: myapp
  tag: "1.0.0"
  pullPolicy: IfNotPresent

replicaCount: 3

service:
  type: ClusterIP
  port: 80

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

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

autoscaling:
  enabled: false
  minReplicas: 2
  maxReplicas: 10

Template Helpers (_helpers.tpl)

Copy{{- define "my-app.fullname" -}}
{{- if .Values.fullnameOverride }}
{{- .Values.fullnameOverride | trunc 63 | trimSuffix "-" }}
{{- else }}
{{- printf "%s-%s" .Release.Name .Chart.Name | trunc 63 | trimSuffix "-" }}
{{- end }}
{{- end }}

{{- define "my-app.labels" -}}
helm.sh/chart: {{ .Chart.Name }}-{{ .Chart.Version }}
app.kubernetes.io/name: {{ include "my-app.name" . }}
app.kubernetes.io/instance: {{ .Release.Name }}
{{- end }}

Deployment Template

CopyapiVersion: 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:
    spec:
      containers:
      - name: {{ .Chart.Name }}
        image: "{{ .Values.image.repository }}:{{ .Values.image.tag }}"
        resources:
          {{- toYaml .Values.resources | nindent 12 }}

Multi-Environment Configuration

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

Install with environment:

Copyhelm install my-app ./my-app -f values-prod.yaml -n production

Common Patterns

Conditional Resources

Copy{{- if .Values.ingress.enabled }}
apiVersion: networking.k8s.io/v1
kind: Ingress
...
{{- end }}

Iterating Lists

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

Validation Commands

Copyhelm lint my-app/
helm template my-app ./my-app --dry-run
helm install my-app ./my-app --dry-run --debug

Best Practices

1. Use semantic versioning
2. Document all values with comments
3. Use template helpers for repeated logic
4. Pin dependency versions explicitly
5. Include NOTES.txt with usage instructions
6. Add labels consistently
7. Test in all environments