PHP message: PHP Fatal error: Interface ‘SessionHandlerInterface’ not found in /var/www/src/vendor/ laravel/framework/src/Illuminate/Session/FileSessionHandler.php on line 10

Today I successfully installed my first October CMS project locally via composer / command line. The installation was pretty straightforward and worked surprisingly well on my Alpine Linux docker container which includes NGINXPHP-FPM and MariaDB.

However, when I tried to open the front-end I got the following error.

After a quick research I found the solution on Stackoverflow. I basically forgot to install the PHP extension php7-session inside my docker container. I manually installed the missing extension, but also updated my Dockerfile in case I have to rebuild my container.

After that I manually killed all PHP processes to make sure php-fpm loads the new extension with the next page reload.