Helm Tutorial: Managing Kubernetes Applications

What is Helm?

Helm is the package manager for Kubernetes. It lets you define, install, and upgrade complex Kubernetes applications using reusable packages called charts. Think of it as apt or brew, but for Kubernetes.

Key Concepts

Term	Description
Chart	A package containing all Kubernetes resource definitions for an application
Release	A running instance of a chart installed in a cluster
Repository	A place where charts are stored and shared
Values	Configuration parameters that customize a chart at install time

Installation

# macOS
brew install helm

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

Verify the installation:

helm version

Adding a Chart Repository

Add the Bitnami repository — one of the most popular sources for production-ready charts:

helm repo add bitnami https://charts.bitnami.com/bitnami
helm repo update

Search for available charts:

helm search repo nginx

Installing a Chart

Install NGINX from Bitnami:

helm install my-nginx bitnami/nginx

The format is helm install <release-name> <repo/chart>. Helm creates all required Kubernetes resources and tracks the release state.

List running releases:

helm list

Customizing with Values

Every chart exposes configurable values. View the defaults:

helm show values bitnami/nginx

Override values at install time using --set or a values file:

# Inline override
helm install my-nginx bitnami/nginx --set replicaCount=2

# File-based override
helm install my-nginx bitnami/nginx -f custom-values.yaml

A custom-values.yaml example:

replicaCount: 2
service:
  type: ClusterIP
resources:
  requests:
    cpu: 100m
    memory: 128Mi

Upgrading a Release

Apply configuration changes or a chart version bump to a running release:

helm upgrade my-nginx bitnami/nginx --set replicaCount=3

Use --install to install when not already present (upsert pattern):

helm upgrade --install my-nginx bitnami/nginx -f custom-values.yaml

Rolling Back

If something goes wrong, roll back to a previous revision:

# Show revision history
helm history my-nginx

# Roll back to revision 1
helm rollback my-nginx 1

Uninstalling a Release

helm uninstall my-nginx

This removes all Kubernetes resources associated with the release. Add --keep-history if you want to retain the release record for auditing.

Creating Your Own Chart

Generate a chart scaffold:

helm create my-app

This produces the standard directory layout:

my-app/
├── Chart.yaml        # Chart metadata (name, version, description)
├── values.yaml       # Default configuration values
└── templates/        # Kubernetes manifest templates
    ├── deployment.yaml
    ├── service.yaml
    └── _helpers.tpl  # Reusable template snippets

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