Summary - CRD

Combine YAML and validation to write a CRD.

Summary: CRD

In this group:

A CRD adds a new type to the API; objects are stored in etcd and managed with kubectl and RBAC.
The name is plural.group; names, scope, versions (served/storage) and openAPIV3Schema.
Custom resource: apiVersion: group/version, kind; additionalPrinterColumns enrich the table.
subresources.status keeps the spec/status split; scale gives kubectl scale and HPA support.
Validation definitions (required, min/max, enum, pattern, default) and CEL rules reject broken data up front.

kubectl apply -f crd.yaml
kubectl apply -f yedek.yaml
kubectl get yd -A

Exercise Printer columns

Write a CRD version's additionalPrinterColumns section (starting with additionalPrinterColumns:): Veritabani (type: string, jsonPath: .spec.veritabani) and Durum (type: string, jsonPath: .status.durum).

Show example solution

additionalPrinterColumns:
  - name: Veritabani
    type: string
    jsonPath: .spec.veritabani
  - name: Durum
    type: string
    jsonPath: .status.durum

Test yourself

What is needed for a custom resource to gain behaviour?
- A more detailed validation definition
- A ClusterRole
- An additional printer column
- A controller (operator) watching and reconciling it
Show answer

A controller (operator) watching and reconciling it — In the next group you'll write an operator.

Give the field a default value.

saklamaGun: {type: integer, minimum: 1, ____: 7}

Show answer

saklamaGun: {type: integer, minimum: 1, default: 7}

Match.

CRD

Type
CR

Object
openAPIV3 definition

Validation
status

Controller report

Next lesson: What is an Operator?

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