private function addRedisNode()
    {
        $builder = new TreeBuilder('redis');
        $node    = $this->getRootNode($builder, 'redis');

        $node
            ->addDefaultsIfNotSet()
            ->children()
                ->scalarNode('connection_id')->defaultNull()->end()
                ->scalarNode('host')->defaultValue('%doctrine_cache.redis.host%')->end()
                ->scalarNode('port')->defaultValue('%doctrine_cache.redis.port%')->end()
                ->scalarNode('password')->defaultNull()->end()
                ->scalarNode('timeout')->defaultNull()->end()
                ->scalarNode('database')->defaultNull()->end()
                ->booleanNode('persistent')->defaultFalse()->end()
            ->end()
        ;

        return $node;
    }