'Get references to given clusters.
:param names: list of cluster names
:return: Dictionary of cluster names to references'

def get_cluster_refs(self, names):

    clusters_ref = {}
    clusters = self._get_all_clusters()
    for name in names:
        if (name not in clusters):
            LOG.error('Compute    cluster:    %s    not    found.', name)
            raise vmdk_exceptions.ClusterNotFoundException(cluster=name)
        clusters_ref[name] = clusters[name]
    return clusters_ref
