Helm Chart Generator

Generate production-ready Helm charts following best practices.

When to Use

•Creating new Helm charts from scratch
•Wrapping external Helm charts
•Converting Kubernetes manifests to Helm charts

Core Rules

1. Use Helm 3 API Version

Set apiVersion: v2 in Chart.yaml.

2. Quote String Values

Always use {{ .Values.foo | quote }} for string values.

3. Use Helper Templates

Define reusable templates in _helpers.tpl for labels and names.

4. Set Secure Defaults

Include securityContext and resources with safe defaults in values.yaml.

5. Support Customization

Allow nodeSelector, tolerations, affinity configuration.

Chart Structure

code

<chart-name>/
├── Chart.yaml
├── values.yaml
├── templates/
│   ├── _helpers.tpl
│   ├── deployment.yaml
│   ├── service.yaml
│   ├── serviceaccount.yaml
│   ├── configmap.yaml
│   ├── hpa.yaml
│   ├── pdb.yaml
│   └── NOTES.txt
└── README.md (optional)

Chart.yaml Template

yaml

apiVersion: v2
name: <chart-name>
description: <description>
type: application
version: 0.1.0
appVersion: "1.0.0"
maintainers:
  - name: <team-name>
    email: <team-email>
keywords:
  - <keyword1>
  - <keyword2>

For Wrapper Charts (External Dependencies)

yaml

apiVersion: v2
name: <chart-name>
description: Wrapper chart for <external-chart>
type: application
version: 0.1.0
appVersion: "1.0.0"

dependencies:
  - name: <external-chart>
    version: <version>
    repository: <helm-repo-url>

# helm repo add <repo-name> <repo-url>
# helm search repo <repo-name>/<chart-name> --versions
# helm show values <repo-name>/<chart-name> --version <version>
# helm dependency update

values.yaml Template

yaml

# Default values for <chart-name>

replicaCount: 2

image:
  repository: <image-repo>
  tag: ""  # Defaults to appVersion
  pullPolicy: IfNotPresent

imagePullSecrets: []
nameOverride: ""
fullnameOverride: ""

serviceAccount:
  create: true
  annotations: {}
  name: ""

podAnnotations: {}
podLabels: {}

podSecurityContext:
  runAsNonRoot: true
  runAsUser: 1000
  fsGroup: 1000
  seccompProfile:
    type: RuntimeDefault

securityContext:
  allowPrivilegeEscalation: false
  readOnlyRootFilesystem: true
  capabilities:
    drop:
      - ALL

service:
  type: ClusterIP
  port: 80

resources:
  requests:
    cpu: 100m
    memory: 128Mi
  limits:
    cpu: 500m
    memory: 512Mi

livenessProbe:
  httpGet:
    path: /healthz
    port: http
  initialDelaySeconds: 10
  periodSeconds: 10

readinessProbe:
  httpGet:
    path: /ready
    port: http
  initialDelaySeconds: 5
  periodSeconds: 5

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

nodeSelector: {}
tolerations: []
affinity: {}

# Pod Disruption Budget
pdb:
  enabled: true
  minAvailable: 1

_helpers.tpl Template

yaml

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

{{/*
Create a default fully qualified app name.
*/}}
{{- define "<chart-name>.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 }}

{{/*
Create chart name and version as used by the chart label.
*/}}
{{- define "<chart-name>.chart" -}}
{{- printf "%s-%s" .Chart.Name .Chart.Version | replace "+" "_" | trunc 63 | trimSuffix "-" }}
{{- end }}

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

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

{{/*
Create the name of the service account to use
*/}}
{{- define "<chart-name>.serviceAccountName" -}}
{{- if .Values.serviceAccount.create }}
{{- default (include "<chart-name>.fullname" .) .Values.serviceAccount.name }}
{{- else }}
{{- default "default" .Values.serviceAccount.name }}
{{- end }}
{{- end }}

Best Practices

Templating

•Use {{ include }} for reusable templates
•Always quote string values: {{ .Values.foo | quote }}
•Use default for fallback values
•Use required for mandatory values

Security

•Never hardcode secrets in values.yaml
•Use podSecurityContext and securityContext by default
•Set restrictive defaults, allow override

Flexibility

•Make image registry configurable for air-gapped environments
•Support nodeSelector, tolerations, affinity
•Include HPA and PDB as optional features

Leaving Room for Imperativeness

When HPA or other controllers manage certain fields, the Helm template should conditionally omit those fields to avoid GitOps conflicts.

Conditional Replicas in Deployment Template

If autoscaling.enabled is true, omit replicas from the Deployment so that HPA controls scaling without conflicting with the Git-tracked value.

yaml

# templates/deployment.yaml
spec:
  {{- if not .Values.autoscaling.enabled }}
  replicas: {{ .Values.replicaCount }}
  {{- end }}

values.yaml Convention

yaml

# replicaCount is ignored when autoscaling.enabled is true
replicaCount: 2

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

ArgoCD ignoreDifferences for Wrapper Charts

When wrapping external charts that do not conditionally omit replicas, configure ArgoCD to ignore diffs:

yaml

apiVersion: argoproj.io/v1alpha1
kind: Application
spec:
  ignoreDifferences:
  - group: apps
    kind: Deployment
    jsonPointers:
    - /spec/replicas

Validation After Generation

bash

helm lint <chart-path>
helm template <release-name> <chart-path> --debug
helm template <release-name> <chart-path> | kubeconform -strict