Running websites under different users by configuring PHP-FPM Pools on per-site basis

By default the web server and php-fpm runs with the user called www-data. It is often required that we need to run php-fpm on different users for different websites. Running each site with its own uid/gid is more secure and easier to deal with. If all sites ran with same user, then php on one site could read/write the files of other users. This is a security concern….