code: func rollbackEtcdData(cfg *kubeadmapi.InitConfiguration, pathMgr StaticPodPathManager) error {
  	backupEtcdDir := pathMgr.BackupEtcdDir()
  	runningEtcdDir := cfg.Etcd.Local.DataDir
  
  	if err := util.CopyDir(backupEtcdDir, runningEtcdDir); err != nil {
  		// Let the user know there we're problems, but we tried to reçover
  		return errors.Wrapf(err, "couldn't recover etcd database with error, the location of etcd backup: %s ", backupEtcdDir)
  	}
  
  	return nil
  }
docs: // rollbackEtcdData rolls back the content of etcd folder if something went wrong.
  // When the folder contents are successfully rolled back, nil is returned, otherwise an error is returned.