kubernetes/extend-resources

The CustomResourceDefinition (CRD) template in ConfigFacets is designed to facilitate the creation and management of Kubernetes CRDs, which are a powerful feature for extending Kubernetes with custom resources.

1. Core Structure

The main section includes essential CRD fields:

{
  "kind": "CustomResourceDefinition",
  "spec": {
    "group": "{{ __CRD_ID__.spec.group }}",
    "names": {
      "kind": "{{ __CRD_ID__.spec.names.kind }}",
      "plural": "{{ __CRD_ID__.spec.names.plural }}",
      "singular": "{{ __CRD_ID__.spec.names.singular }}"
    },
    "scope": "{{ __CRD_ID__.spec.scope }}",
    "versions": "{{ __CRD_ID__.spec.versions }}"
  },
  "facets": ["master"],
  "metadata": "{{ __CRD_ID__.metadata }}",
  "apiVersion": "apiextensions.k8s.io/v1"
}

This core structure defines the API group, resource names, scope, and versions of the custom resource. These are crucial for integrating the new resource type into the Kubernetes API.

2. Optional Features

The template includes separate sections for optional CRD features:

• Short names: Allows defining aliases for the resource, making it easier to use in kubectl commands.

• Conversion strategy: Useful when dealing with multiple versions of a CRD, enabling data conversion between versions.

• Preserving unknown fields: Important for backward compatibility and extensibility of the custom resource.

• Categories: Allows grouping custom resources with built-in resources for better organization.

• List kind: Defines how lists of the custom resource should be named.

3. Flexibility and Reusability

The __CRD_ID__ variable allows for dynamic population of CRD fields, making the template reusable for different custom resources.

4. Modularity

The facet-based design allows users to include only the necessary components for their specific CRD, reducing complexity for simple use cases while allowing for advanced configurations when needed.

Examples

Check Request Body tab section to play around with interactive examples.

Install(Example)

The Curl tab in the request section below provides the curl command for your resource.

curl -s -X POST "https://configfacets.com/apis/repos/kubernetes/extend-resources/v1/resources/collections/customresourcedefinition/exec?format=json" -d '{"facets":["master"],"values":{"basic_crd":{"spec":{"group":"example.com","names":{"kind":"Widget","plural":"widgets","singular":"widget","shortNames":["wg"]},"scope":"Namespaced","versions":[{"name":"v1","schema":{"openAPIV3Schema":{"type":"object","properties":{"spec":{"type":"object","properties":{"size":{"type":"integer"},"color":{"type":"string"}}}}}},"served":true,"storage":true}]},"metadata":{"name":"widgets.example.com"}}},"globalvars":{"__CRD_ID__":"basic_crd"}}' | kubectl apply -f -