Challenge - Operator

Write a structure explaining operator reconcile logic.

Challenge: a Yedek operator

A CRD on its own only stores data; an operator that does the work is needed. The operator will create a CronJob for each Yedek object and write the status of the last backup into status:

Yedek magaza-db  ──reconcile──►  CronJob magaza-db-yedek (0 2 * * *)
                ◄──status─────   sonYedek: 2026-11-03T02:00:00Z, durum: Basarili

You'll set up the skeleton with kubebuilder, then deploy the operator to the cluster and test the result.

Exercise Set up the skeleton

Write three commands: kubebuilder init --domain sirket.com --repo github.com/sirket/yedek-operator; create an API for the Yedek kind in group platform, version v1 (--resource --controller); generate the CRD and RBAC files (make manifests).

Show example solution

kubebuilder init --domain sirket.com --repo github.com/sirket/yedek-operator
kubebuilder create api --group platform --version v1 --kind Yedek --resource --controller
make manifests

Exercise Deploy and test

Write four commands: install the CRD into the cluster (make install); deploy the operator with the ghcr.io/sirket/yedek-operator:0.1.0 image (make deploy IMG=...); apply yedek.yaml; print the {.status.durum} field of the magaza-db object in magaza with jsonpath.

Show example solution

make install
make deploy IMG=ghcr.io/sirket/yedek-operator:0.1.0
kubectl apply -f yedek.yaml
kubectl get yedek magaza-db -n magaza -o jsonpath='{.status.durum}'

Test yourself

What is the benefit of the operator adding an ownerReference to the CronJob it creates?
- The CronJob runs faster
- No RBAC is needed
- Status fills automatically
- When the Yedek object is deleted, the CronJob is removed by the garbage collector too
Show answer

When the Yedek object is deleted, the CronJob is removed by the garbage collector too — The ownership relation leaves cleanup to Kubernetes.

Add a new API type and its controller.

kubebuilder create ____ --group platform --version v1 --kind Yedek

Show answer

kubebuilder create api --group platform --version v1 --kind Yedek

Match.

reconcile

Bring to desired state
ownerReference

Ownership
status

Observed state
make manifests

Generate CRD and RBAC

Next lesson: Challenge - Istio

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