Helm & Kustomize

As Kubernetes applications grow in complexity, managing raw YAML files becomes challenging. Helm and Kustomize are two popular tools that help manage Kubernetes configurations, but they take different approaches. Understanding when and how to use each tool is essential for effective Kubernetes configuration management.

Think of Helm like a package manager (like apt or npm) that bundles applications with their configurations, while Kustomize is like a configuration management tool (like Ansible) that patches and composes existing configurations. Both solve the problem of managing complex Kubernetes configurations, but they do it in different ways.

Why Packaging Matters

Managing Kubernetes applications involves:

Multiple resources - Deployments, Services, ConfigMaps, Secrets, etc.
Environment differences - Development, staging, production configurations
Reusability - Sharing configurations across projects
Versioning - Managing different versions of applications
Dependencies - Applications that depend on other applications

Raw YAML files become unwieldy as applications grow. Packaging tools help by:

Organizing configurations
Enabling reuse
Managing environments
Handling dependencies
Simplifying updates

Helm: The Package Manager

Helm is Kubernetes’ package manager. It uses a templating approach where you define templates with variables that get filled in during deployment.

Helm Concepts

Charts - Packages of pre-configured Kubernetes resources
Templates - YAML files with Go templating syntax
Values - Configuration files that fill template variables
Releases - Installed instances of charts
Repositories - Collections of charts

When to Use Helm

✅ Installing third-party applications (databases, monitoring tools)
✅ Sharing applications as packages
✅ Managing application dependencies
✅ Need for templating and variables
✅ Complex applications with many components

Kustomize: Configuration Management

Kustomize is a configuration management tool built into kubectl. It uses a patching approach where you define a base configuration and apply patches for different environments.

Kustomize Concepts

Base - Base configuration directory
Overlays - Environment-specific patches
Patches - Changes applied to base
Resources - Kubernetes resource files
kustomization.yaml - Configuration file

When to Use Kustomize

✅ Managing environment-specific configurations
✅ Patching existing YAML files
✅ GitOps workflows
✅ Native kubectl integration
✅ Simple configuration management

Comparison

Feature	Helm	Kustomize
Approach	Templating	Patching
Learning Curve	Moderate	Easy
Third-party Charts	Excellent	Limited
Environment Management	Values files	Overlays
Dependencies	Native support	Manual
kubectl Integration	Plugin	Built-in
Complexity	Higher	Lower

Topics

Helm vs Kustomize - Detailed comparison and when to use each

Key Takeaways

Helm is a package manager using templating
Kustomize is configuration management using patching
Helm is better for third-party applications and complex templating
Kustomize is better for environment management and GitOps
Both tools solve configuration management problems differently
You can use both tools together in the same project