private function _getClusterId()
    {
        $oConfig = \OxidEsales\Eshop\Core\Registry::getConfig();
        $sBaseShop = $oConfig->getBaseShopId();
        $sClusterId = $oConfig->getShopConfVar('sClusterId', $sBaseShop);
        if (!$sClusterId) {
            $oUUIDGenerator = oxNew(\OxidEsales\Eshop\Core\UniversallyUniqueIdGenerator::class);
            $sClusterId = $oUUIDGenerator->generate();
            $oConfig->saveShopConfVar("str", 'sClusterId', $sClusterId, $sBaseShop);
        }

        return $sClusterId;
    }