Challenge - Operator
- Docker & Kubernetes course
- Expert
- Lesson 44/47
- 5 min
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: BasariliYou'll set up the skeleton with kubebuilder, then deploy the operator to the cluster and test the result.
Practice 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).
Starter code
# buraya yazSample solution
kubebuilder init --domain sirket.com --repo github.com/sirket/yedek-operator
kubebuilder create api --group platform --version v1 --kind Yedek --resource --controller
make manifestsExpected output
INFO Writing kustomize manifests for you to edit... INFO Writing scaffold for you to edit... INFO api/v1/yedek_types.go INFO internal/controller/yedek_controller.go /home/ali/yedek-operator/bin/controller-gen rbac:roleName=manager-role crd webhook paths="./..." output:crd:artifacts:config=config/crd/bases
Practice 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.
Starter code
# buraya yazSample 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}'Expected output
customresourcedefinition.apiextensions.k8s.io/yedekler.platform.sirket.com created deployment.apps/yedek-operator-controller-manager created yedek.platform.sirket.com/magaza-db created Basarili
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 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 Correct answer
Explanation: The ownership relation leaves cleanup to Kubernetes.
2 Add a new API type and its controller.
kubebuilder create ____ --group platform --version v1 --kind Yedekkubebuilder create api --group platform --version v1 --kind YedekExplanation: create api generates the type and controller skeleton.
3 Match.
| Term | Meaning |
|---|---|
reconcile |
Bring to desired state |
ownerReference |
Ownership |
status |
Observed state |
make manifests |
Generate CRD and RBAC |