When working with Nginx, you'll encounter three crucial directories that handle different aspects of server configuration:

/etc/nginx/
├── conf.d/          # Modular configuration files
├── sites-available/ # All possible site configurations
└── sites-enabled/   # Activated site configurations (symlinks)

The conf.d directory is designed for global server configurations and modules. Files here are typically included with an include directive in nginx.conf:

# Example conf.d/load-balancing.conf
upstream backend {
    server 10.0.0.1:8080;
    server 10.0.0.2:8080;
}

The sites-available directory stores complete virtual host configurations. This is where you define server blocks for individual websites:

# Example sites-available/example.com
server {
    listen 80;
    server_name example.com;
    location / {
        proxy_pass http://backend;
    }
}

Nginx only reads configurations from sites-enabled. This directory typically contains symlinks to files in sites-available:

# Enable a site
ln -s /etc/nginx/sites-available/example.com /etc/nginx/sites-enabled/

# Disable a site
rm /etc/nginx/sites-enabled/example.com

The www-data user is typically created automatically during Nginx installation. To verify:

id www-data
# Should return: uid=33(www-data) gid=33(www-data) groups=33(www-data)

For proper permissions:

# Set ownership for web content
chown -R www-data:www-data /var/www/html

# Set secure permissions
find /var/www/html -type d -exec chmod 755 {} \;
find /var/www/html -type f -exec chmod 644 {} \;

Here's a complete example for load balancing:

# /etc/nginx/conf.d/backend.conf
upstream app_cluster {
    least_conn;
    server 192.168.1.10:8000;
    server 192.168.1.11:8000;
    keepalive 32;
}

# /etc/nginx/sites-available/myapp
server {
    listen 80;
    server_name app.example.com;
    
    location / {
        proxy_pass http://app_cluster;
        proxy_http_version 1.1;
        proxy_set_header Connection "";
    }
}

Remember to test your configuration after changes:

nginx -t && systemctl reload nginx

When working with Nginx, you'll encounter three critical directories that handle server configurations differently. Understanding their purposes and best practices is essential for proper server management.

The conf.d directory is Nginx's primary configuration location. Files here should end with .conf and are automatically loaded when Nginx starts. This is ideal for:

# Example: /etc/nginx/conf.d/example.conf
server {
    listen 80;
    server_name example.com;
    root /var/www/example;
}

This pair works together for configuration management:

• sites-available: Stores all possible configurations
• sites-enabled: Contains symlinks to active configurations

Enable a site with:

ln -s /etc/nginx/sites-available/example.com /etc/nginx/sites-enabled/

Nginx typically runs as www-data:

# Check if user exists
id www-data

# Set permissions
chown -R www-data:www-data /var/www
chmod -R 755 /var/www

Here's a basic load balancing setup in conf.d:

upstream backend {
    server 10.0.0.1:8080;
    server 10.0.0.2:8080;
}

server {
    listen 80;
    location / {
        proxy_pass http://backend;
    }
}

Always test before applying changes:

nginx -t
systemctl reload nginx