public function getSentinelConnection()
    {
        if (!$this->sentinelConnection) {
            if (!$this->sentinels) {
                throw new \Predis\ClientException('No sentinel server available for autodiscovery.');
            }

            $sentinel = array_shift($this->sentinels);
            $this->sentinelConnection = $this->createSentinelConnection($sentinel);
        }

        return $this->sentinelConnection;
    }