Install phpredis

After installing redis, let further install the php package for apache or nginx.
To download and compile phpredis:

git clone https://github.com/phpredis/phpredis
cd phpredis
phpize
./configure
make && make install

Include the compiled extension to php.ini:

touch /etc/php.d/redis.ini
echo extension=redis.so > /etc/php.d/redis.ini

If you use Apache (httpd), restart by:

systemctl restart httpd.service

If you use nginx, restart it by:

systemctl restart php-fpm.service
systemctl restart nginx.service