Helm

Helm is the package manager for Kubernetes. Helm lets you define, install, and upgrade Kubernetes applications using packages called charts. It makes deploying and managing complex apps as easy as installing an app on your phone - just use a "chart" and you're off to the races.

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.