PHP-FPM Multiple Pools on Gentoo Linux

Multiple pools allow different websites to run as different users, providing process isolation and security.

Pool directory

/etc/php/fpm-php8.2/fpm.d/

Step 1 – Create a new pool for site1

Create /etc/php/fpm-php8.2/fpm.d/site1.conf:

[site1]
user  = site1
group = site1

listen = /run/php-fpm/site1.sock
listen.owner = www-data
listen.group = www-data
listen.mode  = 0660

pm = dynamic
pm.max_children      = 10
pm.start_servers     = 2
pm.min_spare_servers = 1
pm.max_spare_servers = 5
pm.max_requests      = 200

; Logging
access.log  = /var/log/php-fpm/site1-access.log
php_flag[display_errors]   = off
php_admin_value[error_log] = /var/log/php-fpm/site1-error.log
php_admin_flag[log_errors]  = on

; Open basedir restriction
php_admin_value[open_basedir] = /var/www/site1:/tmp

Step 2 – Create system user

useradd -r -s /sbin/nologin site1
mkdir -p /var/www/site1/html
chown site1:site1 /var/www/site1/html

Step 3 – Reload PHP-FPM

systemctl reload php-fpm 2>/dev/null || rc-service php-fpm reload

Step 4 – Update Nginx/Apache to use new socket

In the Nginx server block for site1.example.com:

fastcgi_pass unix:/run/php-fpm/site1.sock;