CustomResourceDefinitions

KubernetesのCustomResourceDefinitionsを調べました。

公式ドキュメントのCRDを、そのままデプロイしました。

$ cat resourcedefinition.yaml
apiVersion: apiextensions.k8s.io/v1beta1
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
  # 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
$ kubectl apply -f resourcedefinition.yaml
customresourcedefinition.apiextensions.k8s.io/crontabs.stable.example.com created
$

kubectl proxyを起動します。

$ kubectl proxy
Starting to serve on 127.0.0.1:8001

下記の通りAPIのエンドポイントが作成されていることがわかります。

$ curl http://localhost:8001/apis/stable.example.com/
{
  "kind": "APIGroup",
  "apiVersion": "v1",
  "name": "stable.example.com",
  "versions": [
    {
      "groupVersion": "stable.example.com/v1",
      "version": "v1"
    }
  ],
  "preferredVersion": {
    "groupVersion": "stable.example.com/v1",
    "version": "v1"
  }
$ 

作成したCRDのリソースを作ります。

$ cat my-crontab.yaml 
apiVersion: "stable.example.com/v1"
kind: CronTab
metadata:
  name: my-new-cron-object
spec:
  cronSpec: "* * * * */5"
  image: my-awesome-cron-image
$ kubectl apply -f my-crontab.yaml 
crontab.stable.example.com/my-new-cron-object created
$ kubectl get crontab
NAME                 AGE
my-new-cron-object   34s
$

CRDを削除すると、リソースも削除されます。

$ kubectl delete -f resourcedefinition.yaml 
customresourcedefinition.apiextensions.k8s.io "crontabs.stable.example.com" deleted
$ kubectl apply -f resourcedefinition.yaml 
customresourcedefinition.apiextensions.k8s.io/crontabs.stable.example.com created
$ kubectl get crontab
No resources found.
$