# Kustomize

> Kustomize customizes Kubernetes YAML without templates: a base of manifests plus overlays that patch them for each environment.

- Source: https://www.itwonderlab.com/kustomize/
- Published: 2026-08-14
- Updated: 2026-08-14
- Author: Javier Ruiz Jiménez (https://www.javierruizjimenez.com/)
- Site: IT Wonder Lab (https://www.itwonderlab.com/)

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**Kustomize** is built into [kubectl](https://www.itwonderlab.com/kubectl/) (`kubectl apply -k`). You keep one base and describe per-environment changes, such as replicas, images or namespaces, in overlays. It is an alternative to [Helm](https://www.itwonderlab.com/helm/) values files.

### Key concepts

- **Base** and **overlay**: shared manifests and their variants.
- **Patches**: change fields of existing resources.
- **Generators**: create ConfigMaps and Secrets from files.

### Learn it

Follow [Kubernetes overlays with Kustomize](https://www.itwonderlab.com/kustomize-kubernetes-overlays/). [Argo CD](https://www.itwonderlab.com/argo-cd/) deploys Kustomize directories directly.