'Returns the default_template specified in the [global] section
of the config. Raises NoDefaultTemplateFound if no default cluster
template has been specified in the config.'

def get_default_cluster_template(self):

    default = self.globals.get('default_template')
    if (not default):
        raise exception.NoDefaultTemplateFound(options=self.clusters.keys())
    if (default not in self.clusters):
        raise exception.ClusterTemplateDoesNotExist(default)
    return default
