Helm — Kubernetes Package Manager

Helm — Kubernetes Package Manager

Helm is the package manager for Kubernetes. It bundles multiple Kubernetes manifests into a chart — a reusable, versioned, configurable unit.

Why Helm

Without Helm you manage many YAML files manually. Helm:

• Templates manifests with variables (image tag, replica count, etc.)
• Versions deployments (install, upgrade, rollback)
• Packages applications for sharing via repositories

Installing Helm

# macOS
brew install helm

# Windows (winget)
winget install Helm.Helm

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

Chart Structure

my-chart/
├── Chart.yaml          # chart metadata (name, version, description)
├── values.yaml         # default configuration values
├── templates/
│   ├── deployment.yaml
│   ├── service.yaml
│   ├── ingress.yaml
│   └── _helpers.tpl    # named template helpers
└── charts/             # dependent charts

Chart.yaml:

apiVersion: v2
name: my-app
description: My application chart
version: 1.0.0
appVersion: "2.3.1"

values.yaml

Default values that users can override:

replicaCount: 2

image:
  repository: myrepo/my-app
  tag: "1.0"
  pullPolicy: IfNotPresent

service:
  type: ClusterIP
  port: 80

ingress:
  enabled: false

Template Files

Templates use Go templating. Reference values with {{ .Values.key }}:

templates/deployment.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: {{ .Release.Name }}-app
spec:
  replicas: {{ .Values.replicaCount }}
  template:
    spec:
      containers:
        - name: {{ .Chart.Name }}
          image: "{{ .Values.image.repository }}:{{ .Values.image.tag }}"

Essential Commands

# Add a repository
helm repo add bitnami https://charts.bitnami.com/bitnami
helm repo update

# Search for charts
helm search repo nginx

# Install a chart
helm install my-release bitnami/nginx

# Install with custom values
helm install my-release bitnami/nginx \
  --set replicaCount=3 \
  --values custom-values.yaml

# List installed releases
helm list

# Upgrade a release
helm upgrade my-release bitnami/nginx --set replicaCount=5

# Rollback to previous version
helm rollback my-release 1

# Uninstall
helm uninstall my-release

# Preview rendered templates without installing
helm template my-release ./my-chart

# Check for issues before install
helm lint ./my-chart

Overriding Values at Install

Inline:

helm install my-app ./my-chart \
  --set image.tag=2.0 \
  --set replicaCount=5

Values file:

helm install my-app ./my-chart -f prod-values.yaml

prod-values.yaml:

replicaCount: 5
image:
  tag: "2.0"
ingress:
  enabled: true

Popular Chart Repositories

helm repo add ingress-nginx https://kubernetes.github.io/ingress-nginx
helm repo add cert-manager https://charts.jetstack.io
helm repo add prometheus https://prometheus-community.github.io/helm-charts
helm repo add bitnami https://charts.bitnami.com/bitnami