def _redundancy_routers_for_floatingip(
            self, context, router_id, redundancy_router_ids=None,
            ha_settings_db=None):
        """To be called in update_floatingip() to get the
            redundant router ids.
        """
        if ha_settings_db is None:
            ha_settings_db = self._get_ha_settings_by_router_id(context,
                                                                router_id)
        if ha_settings_db is None:
            return

        e_context = context.elevated()
        router_ids = []
        for r_id in (redundancy_router_ids or
                     self._get_redundancy_router_ids(e_context, router_id)):
            router_ids.append(r_id)

        return router_ids