@RequiresSession
  public List<RepositoryVersionEntity> findRepositoriesWithVersionDefinitions() {
    final TypedQuery<RepositoryVersionEntity> query = entityManagerProvider.get().createNamedQuery(
        "repositoryVersionsFromDefinition", RepositoryVersionEntity.class);
    return daoUtils.selectList(query);
  }
Retrieves repository version when they are loaded by a version definition
file. This will not return all repositories - it will only return those
which have a non-NULL VDF.

@return a list of repositories created by VDF, or an empty list when there
        are none.
ambari-server/src/main/java/org/apache/ambari/server/orm/dao/RepositoryVersionDAO.java