Helm

Helm is the package manager for Kubernetes. It makes deploying and managing complex apps as easy as installing an app on your phone—just use a "chart" (a package of Kubernetes resources).

What is Helm?

Helm lets you define, install, and upgrade Kubernetes applications using packages called charts.

Benefits of Using Helm

  • Simplifies Deployment: Bundle all your resources in one chart for easy deployment.
  • Versioning: Upgrade and roll back apps with a single command.
  • Reuse: Share charts across teams and environments.
  • Customization: Use templates and values to adapt to any setup.
  • Dependency Management: Charts can depend on other charts.

Helm Architecture

  • Helm Client: Command-line tool for managing charts.
  • Helm Server (Tiller): Only in Helm v2. In Helm v3+, the client talks directly to the Kubernetes API server (no Tiller).

How Helm Works

  • Charts: Collections of files describing Kubernetes resources.
  • Values Files: Override default settings for different environments.
  • Templates: Dynamically generate manifests.
  • Releases: Each deployment of a chart is a release.
  • Repositories: Collections of charts you can share and reuse.

Creating and Using Helm Charts

Creating a Helm Chart

To create a new Helm chart:

helm create my-chart

This generates: 

my-chart/
  Chart.yaml          # Chart metadata
  values.yaml         # Default configuration values
  charts/             # Dependency charts
  templates/          # Kubernetes resource templates

Example Chart.yaml

apiVersion: v2
name: my-chart
version: 0.1.0
description: A Helm chart for Kubernetes

Advanced Helm Features

  • Hooks: Allow you to run scripts at specific points in a release lifecycle.
  • Lifecycle Management: Manage the lifecycle of applications with upgrade and rollback capabilities.
  • Managing Dependencies: Use the requirements.yaml file to manage chart dependencies.

Customizing Helm Charts

Customize charts for different environments by using values files and templates to override default settings.

Best Practices

  • Version Control: Keep your charts in version control for easy tracking and collaboration.
  • Testing: Test your charts in different environments to ensure compatibility.
  • Security: Regularly update your charts to include the latest security patches.
  • Documentation: Provide clear documentation for using and customizing your charts.