code: func getSubnetIDForLB(compute *gophercloud.ServiceClient, node v1.Node) (string, error) {
  	ipAddress, err := nodeAddressForLB(&node)
  	if err != nil {
  		return "", err
  	}
  
  	instanceID := node.Spec.ProviderID
  	if ind := strings.LastIndex(instanceID, "/"); ind >= 0 {
  		instanceID = instanceID[(ind + 1):]
  	}
  
  	interfaces, err := getAttachedInterfacesByID(compute, instanceID)
  	if err != nil {
  		return "", err
  	}
  
  	for _, intf := range interfaces {
  		for _, fixedIP := range intf.FixedIPs {
  			if fixedIP.IPAddress == ipAddress {
  				return fixedIP.SubnetID, nil
  			}
  		}
  	}
  
  	return "", ErrNotFound
  }
docs: // getSubnetIDForLB returns subnet-id for a specific node