Helm Documentation

🎯 Prerequisites

• Kubernetes cluster
• kubectl configured to communicate with your cluster
• Helm installed on your local machine

📥 Installing Helm

Download and install Helm from the official Helm GitHub repository:

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

Verify the installation:helm version

📚 Helm Basics

📁 Helm Repositories

Helm uses repositories to distribute charts. The default repository is https://charts.helm.sh/stable.

Add a repository: helm repo add my-repo https://example.com/repo

Update your repository to get the latest charts: helm repo update

Searching for Charts

Search for available charts: helm search repo nginx

Installing a Chart : helm install my-release my-repo/my-chart

Listing Installed Releases helm list

Upgrading a Release

To upgrade an existing release: helm upgrade my-release my-repo/my-chart

Uninstall a release:helm uninstall my-release

📜 Helm Charts

Creating a New Chart

Create a new Helm chart: helm create my-chart

This command creates a directory structure for your chart:

graphql

my-chart/
  Chart.yaml          # A YAML file containing information about the chart
  values.yaml         # The default configuration values for this chart
  charts/             # A directory containing any dependencies
  templates/          # A directory of templates that generate Kubernetes manifests

The Chart.yaml file contains metadata about the chart:

apiVersion: v2
name: my-chart
description: A Helm chart for Kubernetes
version: 0.1.0
appVersion: "1.16.0"

Customizing Templates

Helm templates use the Go templating language. For example, a basic deployment template might look like this:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: {{ .Values.app.name }}
spec:
  replicas: {{ .Values.app.replicaCount }}
  template:
    metadata:
      labels:
        app: {{ .Values.app.name }}
    spec:
      containers:
        - name: {{ .Values.app.name }}
          image: "{{ .Values.app.image }}"
          ports:
            - containerPort: {{ .Values.app.port }}

Using values.yaml

The values.yaml file contains default configuration values:

app:
  name: my-app
  replicaCount: 3
  image: my-app:latest
  port: 80

Override values at installation using --set or a custom values.yaml file:

helm install my-release my-chart --set app.replicaCount=5

#or

helm install my-release my-chart -f my-values.yaml

🪝 Helm Hooks

Helm hooks allow you to perform actions at various points in a release lifecycle. Define hooks in your templates:

apiVersion: batch/v1
kind: Job
metadata:
  name: "{{ .Release.Name }}-test"
  annotations:
    "helm.sh/hook": test-success
spec:
  template:
    spec:
      containers:
      - name: test
        image: busybox
        command: ['sh', '-c', 'echo The test is successful!']
      restartPolicy: Never