$ kind create cluster
$ docker exec -it 9b3645be73eb bash
root@kind-control-plane:/# mkdir -p  /etc/systemd/system/containerd.service.d
root@kind-control-plane:/# touch /etc/systemd/system/containerd.service.d/http-proxy.conf
root@kind-control-plane:/# echo "[Service]" >> /etc/systemd/system/containerd.service.d/http-proxy.conf
root@kind-control-plane:/# echo "Environment=\"HTTPS_PROXY=http://10.239.120.56:913\"" >> /etc/systemd/system/containerd.service.d/http-proxy.conf
root@kind-control-plane:/# echo "Environment=\"HTTP_PROXY=http://10.239.120.56:913\"" >> /etc/systemd/system/containerd.service.d/http-proxy.conf
root@kind-control-plane:/# echo "Environment=\"NO_PROXY=localhost,127.0.0.1,.intel.com\"" >> /etc/systemd/system/containerd.service.d/http-proxy.conf
root@kind-control-plane:/# systemctl daemon-reload
root@kind-control-plane:/# systemctl restart containerd
root@kind-control-plane:/# exit

$ kubebuilder init --domain my.domain --repo my.domain/CronJob
$ kubebuilder create api --group batch --version v1 --kind CronJob
$ kubebuilder create webhook --group batch --version v1 --kind CronJob --defaulting --programmatic-validation

edit
api/v1/cronjob_types.go
api/v1/cronjob_webhook.go
controllers/cronjob_controller.go

in controllers/cronjob_controller.go, this line will generate admission in role.yaml
//+kubebuilder:rbac:groups=batch,resources=jobs,verbs=update;list;watch;create;update;delete

$ go get github.com/robfig/cron
$ make manifests

$ make 
will update api/v1/zz_generated.deepcopy.go

edit 
config/crd/kustomization.yaml
config/default/kustomization.yaml
config/manager/kustomization.yaml

make docker-build docker-push IMG=chenhaochuan82/cronjob:v0.1
make deploy IMG=chenhaochuan82/cronjob:v0.2

edit
config/samples/batch_v1_cronjob.yaml
$ kubectl apply -f config/samples/batch_v1_cronjob.yaml