CRD example

cronscale-crd.yaml

apiVersion: apiextensions.k8s.io/v1beta1
kind: CustomResourceDefinition
metadata:
  # name must match the spec fields below, and be in the form: <plural>.<group>
  name: cronscales.captainjustin.space
spec:
  # group name to use for REST API: /apis/<group>/<version>
  group: stable.captainjustin.space
  # list of versions supported by this CustomResourceDefinition
  versions:
    - name: v1
      # Each version can be enabled/disabled by Served flag.
      served: true
      # One and only one version must be marked as the storage version.
      storage: true
  # either Namespaced or Cluster
  scope: Namespaced
  names:
    # plural name to be used in the URL: /apis/<group>/<version>/<plural>
    plural: cronscales
    # singular name to be used as an alias on the CLI and for display
    singular: cronscale
    # kind is normally the CamelCased singular type. Your resource manifests use this.
    kind: CronScale
    # shortNames allow shorter string to match your resource on the CLI
    shortNames:
      - cs
  preserveUnknownFields: false
  validation:
    openAPIV3Schema:
      type: object
      properties:
        spec:
          type: object
          properties:
            cronSpec:
              type: string
            scaleTargetRef:
              type: object
              properties:
                apiVersion:
                  type: string
                kind:
                  type: string
                name:
                  type: string
            minReplicas:
              type: integer
            maxReplicas:
              type: integer
            targetCPUUtilizationPercentage:
              type: integer

cronscale-nginx.yaml

apiVersion: "captainjustins.space/v1"
kind: CronScale
metadata:
  name: scale-down-at-9pm
spec:
  cronSpec: "0 21 * * *"
  scaleTargetRef:
    apiVersion: "extensions/v1beta1"
    kind: "deployment"
    name: "nginx"
  minReplicas: 2
  maxReplicas: 4
  targetCPUUtilizationPercentage: 60
---
apiVersion: "captainjustin.space/v1"
kind: CronScale
metadata:
  name: scale-up-at-6am
spec:
  cronSpec: "0 6 * * *"
  scaleTargetRef:
    apiVersion: "extensions/v1beta1"
    kind: "deployment"
    name: "nginx"
  minReplicas: 4
  maxReplicas: 8
  targetCPUUtilizationPercentage: 40