Kustomize

Template-free customization of Kubernetes manifests. Prefer plain YAML, small patches, and explicit composition over copying entire files per environment.

When to use this skill

• Structuring repos with a shared base and environment overlays
• Patching upstream or third-party manifests without forking
• Generating ConfigMaps and Secrets from files or literals
• Changing images, labels, namespaces, and cross-cutting metadata consistently
• Validating rendered YAML before apply or GitOps sync

Layout

Keep the base environment-agnostic; put environment differences in overlays.

myapp/
  base/
    kustomization.yaml
    deployment.yaml
    service.yaml
  overlays/
    dev/
      kustomization.yaml
      patches/
    staging/
      kustomization.yaml
    prod/
      kustomization.yaml
      patches/

Minimal kustomization.yaml