code: func (i *Instances) List(nameFilter string) ([]types.NodeName, error) {
  	glog.V(4).Infof("openstack List(%v) called", nameFilter)
  
  	opts := servers.ListOpts{
  		Name:   nameFilter,
  		Status: "ACTIVE",
  	}
  	pager := servers.List(i.compute, opts)
  
  	ret := make([]types.NodeName, 0)
  	err := pager.EachPage(func(page pagination.Page) (bool, error) {
  		sList, err := servers.ExtractServers(page)
  		if err != nil {
  			return false, err
  		}
  		for i := range sList {
  			ret = append(ret, mapServerToNodeName(&sList[i]))
  		}
  		return true, nil
  	})
  	if err != nil {
  		return nil, err
  	}
  
  	glog.V(3).Infof("Found %v instances matching %v: %v",
  		len(ret), nameFilter, ret)
  
  	return ret, nil
  }
docs: // List lists node names