What is HELM | Why We Need HELM | Create HELM Chart?

Helm is a package manager for Kubernetes applications. It is a CNCF-graduated project (Cloud Native Computing Foundation) and is actively maintained by the community.

Key Capabilities of Helm

Helm simplifies Kubernetes application deployment and management by offering the following capabilities:

Creating Helm charts from scratch
Packaging charts for distribution
Managing repositories for chart storage
Installing and uninstalling charts in Kubernetes clusters
Handling the release cycle of installed charts

Why Do We Need HELM?

Deploying applications on Kubernetes requires managing multiple resources such as pods, services, deployments, and replica sets. Each of these requires YAML manifest files. As applications grow in complexity, maintaining and managing these manifest files becomes cumbersome. Helm solves this problem by packaging Kubernetes resources into reusable charts.

Features of Helm

A Helm Chart is a collection of YAML files that describe Kubernetes resources, making deployment and management easier. Helm provides the following benefits:

Simplifies defining, installing, and upgrading complex applications
Allows easy versioning, sharing, and publishing of charts
Enables using and modifying pre-existing charts from repositories instead of creating new ones from scratch
Packages multiple Kubernetes YAML manifests into a single deployable unit
Allows searching for charts in Artifact Hub or Helm Hub

Advantages of HELM Charts

Manages complexity – Reduces manual effort by bundling manifests into a single chart
Easy to share – Charts can be shared via public or private repositories
Simplifies upgrades – Upgrading applications is seamless
Rollback capability – Easily revert to previous versions when needed

Installing HELM

Helm can be installed using a binary release or an automated script.

Install Helm from Binary:

Download the latest Helm binary from Helm Official Docs.
Extract the folder.
Move the binary to the desired destination (e.g., /usr/local/bin/helm).

Install Helm via Script:

curl -fsSL -o get_helm.sh https://raw.githubusercontent.com/helm/helm/main/scripts/get-helm-3
chmod 700 get_helm.sh
./get_helm.sh

Creating Your First HELM Chart

Open a terminal and run the following command to create a Helm chart for your service:

helm create hello-world

Navigate to the newly created directory:

cd hello-world

Structure of a HELM Chart

hello-world
├── charts/                  # Dependencies (other Helm charts)
├── Chart.yaml               # Chart metadata
├── templates/               # YAML templates (Deployment, Service, etc.)
│   ├── deployment.yaml
│   ├── service.yaml
│   ├── ingress.yaml
│   ├── _helpers.tpl         # Stores reusable templates or A place to put template helpers that you can re-use throughout the chart
│   ├── NOTES.txt            # The "help text" for your chart. This will be displayed to your users when they run helm install.
│   ├── tests/               # Helm test files
│   └── serviceaccount.yaml
└── values.yaml              # Default configuration values

Chart.yaml: Defines the name, description, version, and dependencies.
values.yaml: Contains default values for your templates.
templates/: Contains Kubernetes manifests but with Helm templating.

This file contains the default values for a chart. These values may be overridden by users during helm install or helm upgrade.

Basic HELM Commands

helm search              # Search for Helm charts
helm search hub          # Search charts in Artifact Hub
helm search repo         # Search charts in a repository
helm install             # Install a Helm chart
helm install <release_name> <chart_name>  # Install a chart with a release name
helm status <release_name>  # Check the status of a release
helm upgrade <release_name> <chart_name>  # Upgrade an installed chart
helm rollback <release_name> <revision>  # Rollback to a previous version
helm uninstall <release_name>  # Uninstall a Helm release
helm list               # List all installed releases

By leveraging Helm, you can streamline Kubernetes application deployment and management, making it more efficient and scalable.