Helm Charts

# Install Helm
# macOS
brew install helm

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

# Verify installation
helm version

# Add popular chart repositories
helm repo add bitnami https://charts.bitnami.com/bitnami
helm repo add ingress-nginx https://kubernetes.github.io/ingress-nginx
helm repo add jetstack https://charts.jetstack.io
helm repo add prometheus-community https://prometheus-community.github.io/helm-charts

# Update repositories
helm repo update

# Search for charts
helm search repo nginx
helm search repo postgres

# Install PostgreSQL from Bitnami
helm install my-postgres bitnami/postgresql \
  --namespace database \
  --create-namespace \
  --set auth.postgresPassword=mySecretPassword \
  --set auth.database=myapp \
  --set primary.persistence.size=10Gi

# Install with a values file
helm install my-postgres bitnami/postgresql \
  --namespace database \
  --create-namespace \
  -f postgres-values.yaml

# List installed releases
helm list -A

# Get release status
helm status my-postgres -n database

# View generated manifests
helm get manifest my-postgres -n database

# Upgrade a release
helm upgrade my-postgres bitnami/postgresql \
  --namespace database \
  -f postgres-values.yaml \
  --set primary.persistence.size=20Gi

# Rollback to a previous revision
helm rollback my-postgres 1 -n database

# Uninstall a release
helm uninstall my-postgres -n database

# Create a new chart
helm create my-web-app

# Chart directory structure:
# my-web-app/
#   Chart.yaml          # Chart metadata
#   values.yaml         # Default configuration values
#   charts/             # Dependency charts
#   templates/          # Kubernetes manifest templates
#     deployment.yaml
#     service.yaml
#     ingress.yaml
#     hpa.yaml
#     serviceaccount.yaml
#     _helpers.tpl      # Template helpers
#     NOTES.txt         # Post-install notes
#   .helmignore         # Files to ignore

# Chart.yaml
apiVersion: v2
name: my-web-app
description: A Helm chart for my web application
type: application
version: 0.1.0          # Chart version
appVersion: "1.0.0"     # Application version
keywords:
  - web
  - nodejs
  - api
maintainers:
  - name: DevOps Team
    email: devops@company.com
dependencies:
  - name: postgresql
    version: "13.x.x"
    repository: "https://charts.bitnami.com/bitnami"
    condition: postgresql.enabled
  - name: redis
    version: "18.x.x"
    repository: "https://charts.bitnami.com/bitnami"
    condition: redis.enabled

# values.yaml
replicaCount: 3

image:
  repository: myregistry/my-web-app
  tag: "1.0.0"
  pullPolicy: IfNotPresent

service:
  type: ClusterIP
  port: 80

ingress:
  enabled: true
  className: nginx
  hosts:
    - host: app.example.com
      paths:
        - path: /
          pathType: Prefix
  tls:
    - secretName: app-tls
      hosts:
        - app.example.com

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

autoscaling:
  enabled: true
  minReplicas: 2
  maxReplicas: 10
  targetCPUUtilizationPercentage: 70

env:
  NODE_ENV: production
  LOG_LEVEL: info

postgresql:
  enabled: true
  auth:
    database: myapp

redis:
  enabled: false

# templates/deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: {{ include "my-web-app.fullname" . }}
  labels:
    {{- include "my-web-app.labels" . | nindent 4 }}
spec:
  {{- if not .Values.autoscaling.enabled }}
  replicas: {{ .Values.replicaCount }}
  {{- end }}
  selector:
    matchLabels:
      {{- include "my-web-app.selectorLabels" . | nindent 6 }}
  template:
    metadata:
      labels:
        {{- include "my-web-app.selectorLabels" . | nindent 8 }}
    spec:
      containers:
      - name: {{ .Chart.Name }}
        image: "{{ .Values.image.repository }}:{{ .Values.image.tag }}"
        imagePullPolicy: {{ .Values.image.pullPolicy }}
        ports:
        - containerPort: 3000
        env:
        {{- range $key, $value := .Values.env }}
        - name: {{ $key }}
          value: {{ $value | quote }}
        {{- end }}
        resources:
          {{- toYaml .Values.resources | nindent 10 }}

# Lint your chart
helm lint my-web-app/

# Render templates locally (dry run)
helm template my-release my-web-app/ -f production-values.yaml

# Install your chart
helm install my-release my-web-app/ -f production-values.yaml -n production

# Package the chart for distribution
helm package my-web-app/

# Push to an OCI registry
helm push my-web-app-0.1.0.tgz oci://ghcr.io/myorg/charts