filteredClusters := make(proto.MessageSlice, 0, len(clusters))
	for _, cluster := range clusters {
		if filter.Verify(cluster) {
			filteredClusters = append(filteredClusters, cluster)
		}
	}
	out, err := json.MarshalIndent(filteredClusters, "", "    ")
	if err != nil {
		return err
	}
	if outputFormat == "yaml" {
		if out, err = yaml.JSONToYAML(out); err != nil {
			return err
		}
	}