Helm Lifecycle - From Development to Deployment

Helm Lifecycle: From Development to Deployment

Helm is a package manager for Kubernetes that simplifies application deployment, management, and scaling. Understanding the Helm lifecycle ensures efficient chart development, testing, and deployment. This guide covers:

• Creating a Helm Chart
• Implementing Kubernetes Templates
• Writing Automated Tests
• Packaging and Publishing Charts
• Deploying to Kubernetes
• CI/CD Integration

Helm LifeCycle

1. Creating a Helm Chart

• To start, install Helm:

curl https://raw.githubusercontent.com/helm/helm/main/scripts/get-helm-3 | bash

• Create a Helm chart:

helm create my-app
cd my-app

• Directory structure:

my-app/
├── charts/
├── templates/
│   ├── deployment.yaml
│   ├── service.yaml
│   ├── ingress.yaml
├── Chart.yaml
├── values.yaml

• Modify values.yaml:

replicaCount: 2
image:
  repository: my-app
  tag: latest
  pullPolicy: IfNotPresent
service:
  type: LoadBalancer
  port: 80

2. Implementing Kubernetes Templates

• Helm templates use Go templating to define Kubernetes manifests dynamically.
• Example templates/deployment.yaml:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: {{ .Release.Name }}
spec:
  replicas: {{ .Values.replicaCount }}
  selector:
    matchLabels:
      app: {{ .Release.Name }}
  template:
    metadata:
      labels:
        app: {{ .Release.Name }}
    spec:
      containers:
      - name: my-app
        image: {{ .Values.image.repository }}:{{ .Values.image.tag }}
        ports:
        - containerPort: 80

• Render and validate templates:

helm template my-app ./

3. Writing Automated Tests

• Helm includes testing via helm test. Add a test in templates/tests/test-connection.yaml:

apiVersion: v1
kind: Pod
metadata:
  name: "{{ .Release.Name }}-test"
spec:
  containers:
  - name: curl
    image: curlimages/curl
    command: ['curl', '--fail', 'http://my-app.default.svc.cluster.local']

• Run tests:

helm test my-app

4. Packaging and Publishing Charts

• Package the Helm chart:

helm package my-app

• Create an index file for a Helm repository:

helm repo index .

• Publish to GitHub Pages:

git add .
git commit -m "Publish Helm chart"
git push origin main

• Enable GitHub Pages under Settings > Pages, selecting main as the source.
• Add the repository:

helm repo add myrepo https://<your-username>.github.io/helm-charts/
helm repo update

5. Deploying to Kubernetes

• Install the Helm chart:

helm install my-app myrepo/my-app --namespace default --create-namespace

• Verify the deployment:

kubectl get pods
kubectl get svc

6. CI/CD Integration

• Use GitHub Actions for automated Helm chart deployment.
• Example .github/workflows/helm-deploy.yml:

name: Helm Deploy
on:
  push:
    branches:
      - main
jobs:
  deploy:
    runs-on: ubuntu-latest
    steps:
    - name: Checkout repository
      uses: actions/checkout@v3
    - name: Install Helm
      run: curl https://raw.githubusercontent.com/helm/helm/main/scripts/get-helm-3 | bash
    - name: Package Helm chart
      run: helm package my-app
    - name: Publish chart
      run: |
        helm repo index . --url https://<your-username>.github.io/helm-charts/
        git add .
        git commit -m "Update Helm chart"
        git push origin main

Conclusion

By following the Helm lifecycle, you can efficiently create, test, package, publish, and deploy applications to Kubernetes. CI/CD automation ensures consistency and reliability in your deployments.