[k8s] CustomResourceDefinitions

#Kubernetes

CustomResourceDefinitions는 새로운 종류의 kubernetes 리소스를 정의할 수 있게 해주는 부가기능이다.
deployment나 cronjob 같은 리소스 단위를 직접 추가하는 것이다.

나는 여기서 crontab이라는 리소스 단위를 추가해보려 한다.

cronjob은 있지만 crontab이라는 리소스는 기본적으로 존재하지 않는다.

CustomResourceDefinitions 정의

다음과 같이 yaml 구성을 정의한다.

apiVersion: apiextensions.k8s.io/v1
kind: CustomResourceDefinition
metadata:
  # name must match the spec fields below, and be in the form: <plural>.<group>
  name: crontabs.stable.example.com
spec:
  # group name to use for REST API: /apis/<group>/<version>
  group: stable.example.com
  # 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
      schema:
        openAPIV3Schema:
          type: object
          properties:
            spec:
              type: object
              properties:
                cronSpec:
                  type: string
                image:
                  type: string
                replicas:
                  type: integer
  # either Namespaced or Cluster
  scope: Namespaced
  names:
    # plural name to be used in the URL: /apis/<group>/<version>/<plural>
    plural: crontabs
    # singular name to be used as an alias on the CLI and for display
    singular: crontab
    # kind is normally the CamelCased singular type. Your resource manifests use this.
    kind: CronTab
    # shortNames allow shorter string to match your resource on the CLI
    shortNames:
    - ct