[SOLVED] Class 'RedisCluster' not found

Hi Friends,
I’ve just “installed” Nextcloud 15.0.2 on Debian 9, and now running it obtain on Apache log this error:

[:error] [pid 12294] [client 88.149.168.193:57936] PHP Fatal error: Uncaught Error: Class 'RedisCluster' not found in /var/www/nextcloud/public_html/config/config.php:1176\nStack trace:\n#0 /var/www/nextcloud/public_html/lib/private/Config.php(214): include()\n#1 /var/www/nextcloud/public_html/lib/private/Config.php(63): OC\\Config->readData()\n#2 /var/www/nextcloud/public_html/lib/base.php(140): OC\\Config->__construct('/var/www/nextcl...')\n#3 /var/www/nextcloud/public_html/lib/base.php(591): OC::initPaths()\n#4 /var/www/nextcloud/public_html/lib/base.php(1068): OC::init()\n#5 /var/www/nextcloud/public_html/index.php(40): require_once('/var/www/nextcl...')\n#6 {main}\n thrown in /var/www/nextcloud/public_html/config/config.php on line 1176

This my Redis Cluster options:

'redis.cluster' => [
        'seeds' => [ // provide some/all of the cluster servers to bootstrap discovery, port required
                'localhost:7000',
                'localhost:7001'
        ],
        'timeout' => 0.0,
        'read_timeout' => 0.0,
        'failover_mode' => \RedisCluster::FAILOVER_ERROR
],

I’ve installed Redis and run it, reload Apache but the error persist.
Where am I wrong?

Many many thanks!

Davide

Solved:

need to install “php-redis”

Thanks!