kustomize/functions/examples/validator-resource-requests/README.md

Validation

This is an example of implementing a validation function.

This example is written in go and uses the kyaml libraries for parsing the input and writing the output. Writing in go is not a requirement.

Function implementation

The function is implemented as an image, and built using make image.

The template is implemented as a go program, which reads a collection of input Resource configuration, and looks for invalid configuration.

Function invocation

The function is invoked by authoring a local Resource with metadata.annotations.[config.k8s.io/function] and running:

kustomize config run local-resource/

This exists non-zero if there is an error.

Running the Example

Run the validator with:

kustomize config run local-resource/

This will return an error:

cpu-requests missing for container nginx

Now uncomment the resource reservations and run again:

kustomize config run local-resource/

This will return success