> ## Documentation Index
> Fetch the complete documentation index at: https://notes.kodekloud.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Kustomize vs Helm

> This article compares Helm and Kustomize, two tools for managing Kubernetes manifests, highlighting their strengths, workflows, and trade-offs.

In this article, we’ll compare **Helm** and **Kustomize**—two popular methods for managing Kubernetes manifests across different environments. Understanding their strengths, workflows, and trade-offs will help you select the best fit for your project.

## How Helm Works: Go-Templating in YAML

Helm uses Go templates to inject dynamic values into your Kubernetes manifests. Placeholders in the form of `{{ .Values.variable }}` are replaced at deploy time based on a `values.yaml` file.

```yaml theme={null}
# templates/nginx-deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: {{ .Values.name }}
spec:
  replicas: {{ .Values.replicaCount }}
  selector:
    matchLabels:
      app: {{ .Values.name }}
  template:
    metadata:
      labels:
        app: {{ .Values.name }}
    spec:
      containers:
        - name: {{ .Chart.Name }}
          image: "nginx:{{ .Values.image.tag }}"
```

```yaml theme={null}
# values.yaml
replicaCount: 1
image:
  tag: "2.4.4"
name: "my-app"
```

When you run `helm install my-app ./chart -f values.yaml`, Helm merges the values into the templates, producing valid Kubernetes YAML:

```yaml theme={null}
apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-app
spec:
  replicas: 1
  selector:
    matchLabels:
      app: my-app
  template:
    metadata:
      labels:
        app: my-app
    spec:
      containers:
        - name: my-chart
          image: "nginx:2.4.4"
```

<Callout icon="lightbulb" color="#1CB2FE">
  Use `--values` (or `-f`) to specify different environment files, e.g., `-f values.prod.yaml`.
</Callout>

## Helm Chart Structure

A typical Helm chart directory might look like:

```text theme={null}
k8s/
├── environments/
│   ├── values.dev.yaml
│   ├── values.stg.yaml
│   └── values.prod.yaml
└── templates/
    ├── nginx-deployment.yaml
    ├── nginx-service.yaml
    ├── db-deployment.yaml
    └── db-service.yaml
```

* **templates/**: Kubernetes manifests with Go templating syntax.
* **environments/**: Separate `values.*.yaml` files for each environment.

## Feature Comparison

| Feature                       | Helm                                                 | Kustomize                      |
| ----------------------------- | ---------------------------------------------------- | ------------------------------ |
| Template Syntax               | Go templates (`{{ }}`)                               | Pure YAML overlays and patches |
| Conditional Logic & Loops     | ✔️ Supports `if`, `range`, custom functions          | ❌ Not supported                |
| Packaging & Versioning        | ✔️ Full-fledged chart packaging, dependencies, hooks | ❌ No built-in packaging        |
| Valid YAML Before Rendering   | ❌ Not valid until `helm template` runs               | ✔️ Always valid YAML           |
| Native Kubernetes Integration | ✔️ Widely adopted, independent CLI                   | ✔️ Built into `kubectl`        |

<Callout icon="triangle-alert" color="#FF6B6B">
  Complex Helm charts with extensive logic can become hard to read and maintain. Ensure you document templates and values clearly.
</Callout>

## Trade-offs: When to Use Each Tool

* **Use Helm if**\
  • You need advanced templating (conditionals, loops, custom functions)\
  • You want packaging, versioning, and chart dependencies\
  • You require lifecycle hooks (e.g., pre-install, post-upgrade)

* **Use Kustomize if**\
  • You prefer pure YAML without an extra rendering step\
  • You want easy-to-read overlays and patches\
  • Your customization needs are straightforward (e.g., changing images, labels)

Balance your project’s complexity and team familiarity when choosing between the two.

<Frame>
  ![The image is a slide comparing Kustomize and Helm, highlighting Helm's features such as being a package manager, providing conditionals, loops, functions, and hooks, and noting that Helm templates are not valid YAML due to Go templating syntax.](https://kodekloud.com/kk-media/image/upload/v1752880933/notes-assets/images/Kustomize-Kustomize-vs-Helm/kustomize-vs-helm-comparison-slide.jpg)
</Frame>

## References

* [Helm Documentation](https://helm.sh/docs/)
* [Kustomize Documentation](https://kustomize.io/)
* [Kubernetes Basics](https://kubernetes.io/docs/concepts/overview/what-is-kubernetes/)

<CardGroup>
  <Card title="Watch Video" icon="video" cta="Learn more" href="https://learn.kodekloud.com/user/courses/kustomize/module/414dd6d1-c083-49c0-8003-114e0ce66e15/lesson/3bd51d55-c169-4207-9fcc-70ac7bb0082e" />
</CardGroup>