Helm Chart Basics — Kubernetes Package Management

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

# macOS
brew install helm

# Check version
helm version

# Add the official stable repo
helm repo add stable https://charts.helm.sh/stable
helm repo add bitnami https://charts.bitnami.com/bitnami
helm repo add ingress-nginx https://kubernetes.github.io/ingress-nginx

# List repos
helm repo list

# Update repos
helm repo update

# Search charts
helm search repo nginx
helm search repo bitnami/postgresql

# Basic install
helm install my-nginx ingress-nginx/ingress-nginx

# Specify a namespace
helm install my-nginx ingress-nginx/ingress-nginx   --namespace ingress-nginx   --create-namespace

# Customize with a values.yaml file
helm install my-app bitnami/wordpress -f custom-values.yaml

# Override values from the command line
helm install my-pg bitnami/postgresql   --set auth.postgresPassword=MySecretPass   --set primary.persistence.size=20Gi

# Dry run (preview without deploying)
helm install my-app bitnami/nginx --dry-run --debug

# Upgrade (install if missing)
helm upgrade --install my-nginx ingress-nginx/ingress-nginx

# List deployed releases
helm list
helm list -A            # All namespaces

# Release status
helm status my-nginx

# Show applied values
helm get values my-nginx

# Release history
helm history my-nginx

# Rollback
helm rollback my-nginx 1    # To revision 1

# Uninstall
helm uninstall my-nginx

helm create mychart

# Generated structure
mychart/
├── Chart.yaml           # Chart metadata
├── values.yaml          # Default values
├── templates/           # Kubernetes resource templates
│   ├── deployment.yaml
│   ├── service.yaml
│   ├── ingress.yaml
│   └── _helpers.tpl     # Shared template helpers
└── charts/              # Dependent charts

# values.yaml
replicaCount: 3

image:
  repository: nginx
  tag: "1.25"
  pullPolicy: IfNotPresent

service:
  type: ClusterIP
  port: 80

resources:
  limits:
    cpu: 500m
    memory: 128Mi
  requests:
    cpu: 100m
    memory: 64Mi

ingress:
  enabled: true
  host: myapp.example.com

# templates/deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: {{ include "mychart.fullname" . }}
  labels:
    {{- include "mychart.labels" . | nindent 4 }}
spec:
  replicas: {{ .Values.replicaCount }}
  template:
    spec:
      containers:
      - name: {{ .Chart.Name }}
        image: "{{ .Values.image.repository }}:{{ .Values.image.tag }}"
        ports:
        - containerPort: {{ .Values.service.port }}
        {{- if .Values.resources }}
        resources:
          {{- toYaml .Values.resources | nindent 10 }}
        {{- end }}

# Preview rendered templates
helm template mychart ./mychart -f my-values.yaml

# Lint
helm lint ./mychart