Kustomize Basics

Cluster Architecture and Configuration / Guide 19 of 103 / Intermediate

• Kubernetes1.36.4
• Cluster4 nodes
• Runtimecontainerd 2.2.6
• CNICalico v3.32.1
• TimeAbout 35 min

Kustomize is built into kubectl, and the embedded version lags the standalone binary. Some field names changed across versions, commonLabels to labels and patchesStrategicMerge to patches among them.

• kustomize (in kubectl)v5.8.1

This guide includes

Use this when one application has to reach several environments without a templating language. This matters because Kustomize is already inside kubectl, and its generated ConfigMap hash is what makes a config change actually roll your Pods.

• finding the Kustomize version embedded in kubectl, which lags the standalone binary
• rendering a base with kubectl kustomize without applying anything
• reading an overlay and the transformers that make it differ from its base
• watching configMapGenerator with behavior: merge combine rather than replace
• changing one literal and seeing the generated name hash change, which is what rolls the Pods

Before you start

• The Deployments and ConfigMaps and Secrets guides.
• kubectl 1.14 or later, which has kustomize built in. Nothing to install.

1. 1

   Nothing to install, and a version worth knowing

2. 2

   The base, rendered

3. 3

   The overlay, and the six transformers worth knowing

4. 4

   Generator behaviour, and applying it

5. 5

   The hash is the feature: a config change rolls the Pods

Official sources

• Declarative management with Kustomize
• Kustomize reference
• kustomization.yaml fields
• ConfigMaps
• JSON Patch (RFC 6902)