Check this thread or else these steps should help,

First clean up the pods running into your k8s cluster using,

$ kubectl delete node --all

then remove data volumes and back-up(if it's not needed) from your host system. Finally, you can stop all the k8s services using the script,

$ for service in kube-apiserver kube-controller-manager kubectl kubelet kube-proxy kube-scheduler; do
      systemctl stop $service
  done
$ yum -y remove kubernetes #if it's registered as a service