[따배쿠] Custom Resource

Custom Resource

 

Custom Resource는 기본적으로 제공되는 리소스(예: Pod, Service, Deployment 등) 외에 사용자가 정의한 리소스

 

즉, Custom Resource Definition 파일에 리소스들의 필요 spec을 정의하고

Custom Resource 파일을 정의하여, 관리자가 원하는 리소스를 생성할 수 있다.

 

실습

 

# Custom Resource Definition 파일 생성

root@master:~# vi resourcedefinition.yaml
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

 

# 생성

root@master:~# kubectl apply -f resourcedefinition.yaml
customresourcedefinition.apiextensions.k8s.io/crontabs.stable.example.com created

 

# 확인

root@master:~# kubectl api-resources
NAME                                SHORTNAMES   APIVERSION                        NAMESPACED   KIND
...
crontabs                            ct           stable.example.com/v1             true         CronTab
...

 

group : stable.example.com/v1

resource : crontabs가 생성되었다.

 

---

# Custom Object 파일 생성

root@master:~# cat > my-crontab.yaml
apiVersion: "stable.example.com/v1"
kind: CronTab
metadata:
  name: my-new-cron-object
spec:
  cronSpec: "* * * * */5"
  image: my-awesome-cron-imager

 

# 생성

root@master:~# kubectl apply -f my-crontab.yaml
crontab.stable.example.com/my-new-cron-object created

 

# 확인

root@master:~# kubectl get crontabs.stable.example.com
NAME                 AGE
my-new-cron-object   14s

---

# 기존 Custom Object 파일 복사

root@master:~# cp my-crontab.yaml my-crontab2.yaml

 

my-crontab > my-crontab2

 

# 새로운 Custom Object 파일 생성

root@master:~# vi my-crontab2.yaml
apiVersion: "stable.example.com/v1"
kind: CronTab
metadata:
  name: my-second-cron-object
  namespace: kube-system
spec:
  cronSpec: "* * * * */5"
  image: my-awesome-cron-image
  replicas: 2

 

# 생성

root@master:~# kubectl apply -f my-crontab2.yaml
crontab.stable.example.com/my-second-cron-object created

 

# 확인

root@master:~# kubectl get crontab -n kube-system
NAME                    AGE
my-second-cron-object   33s

---

# 삭제

root@master:~# kubectl delete -f resourcedefinition.yaml
customresourcedefinition.apiextensions.k8s.io "crontabs.stable.example.com" deleted

 

custom resource definition을 삭제하게 되면, 그에 종속된 리소스들도 삭제되게 된다.

---

[참고 영상]

https://www.youtube.com/watch?v=yAcnjammQV4&list=PLApuRlvrZKohLYdvfX-UEFYTE7kfnnY36&index=12

 

[참고 문서]

https://kubernetes.io/docs/tasks/extend-kubernetes/custom-resources/custom-resource-definitions/

Extend the Kubernetes API with CustomResourceDefinitions