12.4 Creating Your Own Chart

⏱️ ~5 min read

TL;DR: helm create my-chart scaffolds a complete, working chart with example templates. Strip it down to what you need and fill in your app’s specifics. The scaffold follows best practices (labels, helpers, NOTES.txt) from the start.

Scaffolding a New Chart

# Create a new chart with all the boilerplate
helm create my-app

# What gets created:
tree my-app

my-app/
├── Chart.yaml
├── values.yaml
├── charts/
└── templates/
    ├── deployment.yaml
    ├── hpa.yaml
    ├── ingress.yaml
    ├── service.yaml
    ├── serviceaccount.yaml
    ├── _helpers.tpl
    ├── NOTES.txt
    └── tests/
        └── test-connection.yaml

The scaffolded chart deploys nginx by default — replace values and templates for your app.

Minimal Chart Walkthrough

After helm create my-app, the key changes to make:

1. Update Chart.yaml:

name: my-app
description: My Application
version: 0.1.0
appVersion: "1.0.0"

2. Update values.yaml defaults:

replicaCount: 2

image:
  repository: myrepo/my-app    # ← Your actual image
  tag: "1.0.0"
  pullPolicy: IfNotPresent

service:
  type: ClusterIP
  port: 8080                   # ← Your app's port

env:                           # Custom values section
  LOG_LEVEL: info
  DB_HOST: postgres-svc

resources:
  requests:
    cpu: "100m"
    memory: "128Mi"
  limits:
    cpu: "500m"
    memory: "256Mi"

3. Update templates/deployment.yaml to use your custom env section:

# In the containers section, add env vars from values:
        env:
        {{- range $key, $val := .Values.env }}
        - name: {{ $key }}
          value: {{ $val | quote }}
        {{- end }}

Validating Your Chart

# Lint for common errors
helm lint my-app/

# Expected output (clean):
# ==> Linting my-app/
# [INFO] Chart.yaml: icon is recommended
# 1 chart(s) linted, 0 chart(s) failed

# Preview rendered YAML (catch template errors)
helm template test-release my-app/ | head -80

# Preview with custom values
helm template test-release my-app/ --values my-prod-values.yaml

# Validate against the cluster API without installing
helm template test-release my-app/ | kubectl apply --dry-run=server -f -

Environment-Specific Values Files

# Directory structure for multi-environment deployment
config/
├── values-base.yaml     # Shared defaults
├── values-dev.yaml      # Dev overrides
├── values-staging.yaml  # Staging overrides
└── values-prod.yaml     # Prod overrides

# values-prod.yaml — only what differs from base
replicaCount: 5

resources:
  requests:
    cpu: "500m"
    memory: "512Mi"
  limits:
    cpu: "2"
    memory: "1Gi"

ingress:
  enabled: true
  host: app.mycompany.com

autoscaling:
  enabled: true
  minReplicas: 3
  maxReplicas: 20

# Deploy to each environment
helm install my-app ./my-app/ \
  --values config/values-base.yaml \
  --values config/values-prod.yaml \
  --namespace production \
  --create-namespace

Packaging and Sharing a Chart

# Package the chart into a .tgz archive
helm package my-app/
# Creates: my-app-0.1.0.tgz

# Install from archive
helm install my-release ./my-app-0.1.0.tgz

# Create a simple file-based chart repository
mkdir -p helm-repo/charts
mv my-app-0.1.0.tgz helm-repo/charts/
helm repo index helm-repo/   # Creates index.yaml

# Host with any static file server (GitHub Pages, S3, etc.)
# Users add it with:
# helm repo add my-team https://my-bucket.s3.amazonaws.com/helm-repo/

Try It

# Create and validate a minimal chart
helm create webapp

# Lint it
helm lint webapp/

# Preview the default nginx install
helm template my-webapp webapp/ | grep "kind:" | sort -u

# Update the image to a different one
sed -i 's|repository: nginx|repository: nginxdemo/hello|' webapp/values.yaml
sed -i 's|tag: ""|tag: "plain-text"|' webapp/values.yaml

# Install it
helm install my-webapp ./webapp/ \
  --namespace helm-create-demo \
  --create-namespace \
  --set service.type=NodePort

helm list -n helm-create-demo
kubectl get all -n helm-create-demo

# Cleanup
helm uninstall my-webapp -n helm-create-demo
kubectl delete namespace helm-create-demo
rm -rf webapp/

Key Takeaways

✅ Quick Check

Q1: helm lint shows no errors but the deployment fails after helm install. What could cause this?

Q2: You have values-base.yaml with replicaCount: 2 and values-prod.yaml with replicaCount: 5. Which wins if you pass both with --values?

Q3: Can you add custom top-level keys to values.yaml (like env: in the example above) that don’t appear in the upstream chart?