三台独立主机部署Apache、PHP、MySQL的跨主机配置咨询

Alright, let's walk through setting up your distributed LAMP stack—Apache on pc1, PHP-FPM on pc2, MySQL on pc3. I’ve deployed similar split architectures a few times, so here’s a practical, step-by-step guide to get everything talking to each other:

All three machines need to communicate freely (or at least over required ports). Here’s what to do:

• Verify you can ping each PC from the others: run ping pc1-ip from pc2 and pc3, and vice versa. If pings fail, check firewall settings or network routing first.
• Open necessary ports on each machine’s firewall:
  • pc2: Allow traffic on port 9000 (default for PHP-FPM). Use ufw allow 9000/tcp (Debian/Ubuntu) or firewall-cmd --add-port=9000/tcp --permanent && firewall-cmd --reload (RHEL/CentOS).
  • pc3: Allow traffic on port 3306 (MySQL default). Use the same firewall commands but swap 9000 for 3306.
  • pc1: Keep ports 80 (HTTP) and 443 (HTTPS) open for Apache traffic.

Apache relies on PHP-FPM to process PHP files these days, so we need to set up pc2’s PHP-FPM to listen for connections from pc1:

• Install PHP-FPM if you haven’t already: apt install php-fpm (Debian/Ubuntu) or yum install php-fpm (RHEL/CentOS).
• Edit the PHP-FPM pool config file—usually located at /etc/php/{your-php-version}/fpm/pool.d/www.conf (replace {your-php-version} with 7.4, 8.2, etc.):
  • Change listen = 127.0.0.1:9000 to listen = 0.0.0.0:9000 (this makes PHP-FPM listen on all network interfaces).
  • Add or update listen.allowed_clients = pc1-ip-address (restricts access to only pc1, which is more secure than allowing everyone).
• Restart PHP-FPM to apply changes: systemctl restart php-fpm.

Now we need to tell Apache on pc1 to send all .php file requests to pc2’s PHP-FPM service:

• Enable the required Apache modules: a2enmod proxy proxy_fcgi (Debian/Ubuntu) or edit your Apache config to load mod_proxy and mod_proxy_fcgi (RHEL/CentOS). Then restart Apache: systemctl restart apache2.
• Open your Apache site config file (e.g., /etc/apache2/sites-available/your-site.conf) and add this block inside the <Directory /var/www/html> section:

  <FilesMatch \.php$>
      # Replace pc2-ip-address with your actual pc2 IP
      SetHandler "proxy:fcgi://pc2-ip-address:9000"
  </FilesMatch>
  

• Test your Apache config for errors: apache2ctl configtest. If it returns Syntax OK, restart Apache again.
• To test this, create a file called info.php in pc1’s web root (/var/www/html) with this content:

  <?php phpinfo(); ?>
  

  Later, visiting http://pc1-ip/info.php should show you PHP’s info page—confirm the SERVER_ADDR is pc1’s IP and the FPM connection points to pc2.

MySQL defaults to only accepting local connections, so we need to grant access to pc1 and pc2:

• Log into MySQL as root: mysql -u root -p.
• Create a database user that can connect from pc1 and pc2 (replace placeholders with your details):

  -- Create user for pc1
  CREATE USER 'web-app-user'@'pc1-ip-address' IDENTIFIED BY 'strong-password-here';
  -- Create user for pc2 (if your PHP app runs code that connects directly to MySQL)
  CREATE USER 'web-app-user'@'pc2-ip-address' IDENTIFIED BY 'strong-password-here';
  -- Grant privileges to your app's database
  GRANT ALL PRIVILEGES ON your-app-db.* TO 'web-app-user'@'pc1-ip-address';
  GRANT ALL PRIVILEGES ON your-app-db.* TO 'web-app-user'@'pc2-ip-address';
  FLUSH PRIVILEGES;
  

  Pro tip: If all PCs are on a local subnet (like 192.168.1.x), you can use 192.168.1.% instead of individual IPs to allow the whole subnet.
• Edit MySQL’s config file (e.g., /etc/mysql/mysql.conf.d/mysqld.cnf or /etc/my.cnf):
  • Change bind-address = 127.0.0.1 to bind-address = 0.0.0.0 (lets MySQL listen on all interfaces).
• Restart MySQL: systemctl restart mysql.

• PHP Forwarding Test: Visit http://pc1-ip/info.php—you should see the PHP info page, which confirms Apache is successfully sending requests to pc2’s PHP-FPM.
• MySQL Connection Test: Create a file db-test.php in pc1’s web root:

  <?php
  $dbHost = 'pc3-ip-address';
  $dbUser = 'web-app-user';
  $dbPass = 'strong-password-here';
  $dbName = 'your-app-db';
  
  $conn = new mysqli($dbHost, $dbUser, $dbPass, $dbName);
  if ($conn->connect_error) {
      die("Connection failed: " . $conn->connect_error);
  }
  echo "Successfully connected to MySQL on pc3!";
  $conn->close();
  ?>
  

  Visit http://pc1-ip/db-test.php—if you see the success message, your entire stack is working.

• Security: Avoid using 0.0.0.0 for listening addresses unless necessary—restrict to specific IPs/subnets. Use strong passwords, and consider enabling SSL for MySQL connections and Apache-PHP-FPM communication in production.
• Performance: Adjust PHP-FPM’s process pool settings (in www.conf) based on pc2’s resources. For Apache, set a reasonable ProxyTimeout to avoid early timeouts during slow PHP requests.

内容的提问来源于stack exchange，提问作者Abdul Rahman