Nginx Server Blocks with PHP-FPM for Multiple Sites

Nginx server blocks are the Nginx equivalent of Apache virtual hosts: each block serves one website based on the requested domain. Pair each site with its own PHP-FPM pool and Linux user and a problem on one site cannot touch the others. This guide sets up two PHP sites on one Nginx server.

Before you start

A Linux VPS with Nginx and PHP-FPM installed (see the LEMP stack guide).
Domains pointing to the server.
Root or sudo access.

Create a user and folder per site

sudo useradd -m -s /usr/sbin/nologin site1
sudo mkdir -p /var/www/site1.com/public
sudo chown -R site1:site1 /var/www/site1.com
sudo chmod 750 /var/www/site1.com

Let Nginx read the files by adding its user to the site group: sudo usermod -aG site1 www-data (the user is nginx on AlmaLinux). Repeat for site2.

Create a PHP-FPM pool per site

Copy the default pool: on Ubuntu the pools live in /etc/php/8.3/fpm/pool.d/, on AlmaLinux in /etc/php-fpm.d/. Create site1.conf:

[site1]
user = site1
group = site1
listen = /run/php/site1.sock
listen.owner = www-data
listen.group = www-data
pm = ondemand
pm.max_children = 10
pm.process_idle_timeout = 30s
php_admin_value[open_basedir] = /var/www/site1.com:/tmp

On AlmaLinux use nginx for the listen owner and group and a socket path like /run/php-fpm/site1.sock.

Restart PHP-FPM: sudo systemctl restart php8.3-fpm (or php-fpm).

Create the server block

Create /etc/nginx/sites-available/site1.com (AlmaLinux: /etc/nginx/conf.d/site1.com.conf):

server {
    listen 80;
    server_name site1.com www.site1.com;
    root /var/www/site1.com/public;
    index index.php index.html;

    access_log /var/log/nginx/site1.access.log;
    error_log  /var/log/nginx/site1.error.log;

    client_max_body_size 64m;

    location / {
        try_files $uri $uri/ /index.php?$args;
    }

    location ~ \.php$ {
        include fastcgi_params;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
        fastcgi_pass unix:/run/php/site1.sock;
    }

    location ~ /\.(?!well-known) {
        deny all;
    }

    location ~* \.(css|js|jpg|jpeg|png|gif|webp|svg|woff2?)$ {
        expires 30d;
        access_log off;
    }
}

Enable it on Ubuntu: sudo ln -s /etc/nginx/sites-available/site1.com /etc/nginx/sites-enabled/.
Test and reload: sudo nginx -t && sudo systemctl reload nginx.

The try_files line gives WordPress and most PHP frameworks pretty URLs. The dot-file rule blocks access to .git, .env and similar files.

Add HTTPS

sudo certbot --nginx -d site1.com -d www.site1.com

Set a default server

Requests for unknown domains go to the first server block. Add a catch-all that closes the connection so random hostnames do not show one of your sites:

server {
    listen 80 default_server;
    server_name _;
    return 444;
}

What to check afterwards

Each domain shows its own site.
ps aux | grep php-fpm shows workers running as site1 and site2 when the sites are busy.
https://site1.com/.env returns 403.

Troubleshooting

File not found / "Primary script unknown": wrong root or SCRIPT_FILENAME, or PHP-FPM cannot read the files.
502 Bad Gateway: socket path mismatch or the pool failed to start – check journalctl -u php8.3-fpm.
403 on the site: Nginx's user cannot traverse the site folder; check group membership and folder permissions.
SELinux (AlmaLinux): run sudo restorecon -Rv /var/www; allow writes for uploads with the httpd_sys_rw_content_t context.

FAQ: Nginx server blocks

Does Nginx support .htaccess?

No. Rewrite rules go into the server block, which is faster because Nginx doesn't read files on every request.

Why use a separate PHP-FPM pool per site?

Each site runs as its own user, so a hacked site cannot read or modify the others, and you can limit resources per site.

How many sites can one Nginx server host?

As many as RAM and CPU allow; Nginx itself handles thousands of server blocks.

Next steps

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