kustomizationyml

KustomizationYml, commonly written as kustomization.yaml, is the configuration file used by Kustomize to describe a set of Kubernetes manifests and how they should be customized for different environments. The file is usually placed in a directory that serves as a base or an overlay, and it is processed by the kustomize tool or by kubectl kustomize to produce the final manifests. Kustomization.yaml and kustomization.yml are both supported.

A kustomization.yaml declares apiVersion and kind and lists resources to include, along with a set of customization operations. Common fields include: resources; patchesStrategicMerge and patchesJson6902; configMapGenerator and secretGenerator; commonLabels and commonAnnotations; namespace; and images. It may also specify namePrefix or nameSuffix and other transformers.

In practice, a kustomization file is used to build environment specific manifests by layering a base with overlays and patches. The final YAML can be rendered with kustomize build or kubectl kustomize and applied with kubectl apply -f -. This approach helps manage multi environment deployments without duplicating manifests or editing values manually.

Example:

apiVersion: kustomize.config.k8s.io/v1beta1

kind: Kustomization

resources:

- deployment.yaml

- service.yaml

patchesStrategicMerge:

- patch.yaml

configMapGenerator:

- name: app-config

literals:

- log.level=info

secretGenerator:

- name: db-creds

literals:

- username=admin

- password=secret