Custom Apache Handler for Running Multiple PHP Versions Per VirtualHost

When migrating legacy PHP applications or consolidating multiple sites onto a single Linux server, you often need one Apache VirtualHost to run a specific PHP release (such as PHP 7.4 or PHP 8.3) while other VirtualHosts remain on the system default PHP version.

Below are both the modern Apache 2.4 + PHP-FPM (mod_proxy_fcgi) configuration and the fallback CGI ScriptAlias / Action handler for legacy Apache 2.2 servers.

Modern Approach: Apache 2.4 with mod_proxy_fcgi and PHP-FPM Pools

On modern RHEL, Rocky Linux, AlmaLinux, Debian, and Ubuntu servers running Apache 2.4+, the cleanest and highest-performance method is running isolated php-fpm pools for each PHP version (for example via Remi’s RPM repository on RHEL/Rocky or ondrej/php on Ubuntu) and routing .php requests over a Unix domain socket inside the <VirtualHost> block:

<VirtualHost *:443>
    ServerName app.example.com
    DocumentRoot /var/www/app/public

    <Directory /var/www/app/public>
        AllowOverride All
        Require all granted
    </Directory>

    # Route PHP scripts in this VirtualHost to the PHP 8.3 FPM socket
    <FilesMatch "\.php$">
        SetHandler "proxy:unix:/run/opt/remi/php83/php-fpm/www.sock|fcgi://localhost/"
    </FilesMatch>
</VirtualHost>

Using mod_proxy_fcgi with per-version Unix sockets gives you full opcode caching (opcache), process pool isolation, and zero CGI process-spawning overhead.

Legacy Workaround: Apache 2.2 CGI ScriptAlias & Action Handler

When maintaining a legacy CentOS 6 / Apache 2.2 environment where mod_proxy_fcgi is unavailable, you can bind a secondary php-cgi binary (such as PHP 7.4 compiled or installed side-by-side) directly to a single <VirtualHost> using ScriptAlias and Action right before the closing </VirtualHost> tag:

ScriptAlias /php74-cgi /opt/remi/php74/root/usr/bin/php-cgi
Action application/x-httpd-php74 /php74-cgi

<FilesMatch "\.php$">
    SetHandler application/x-httpd-php74
</FilesMatch>

Security & Verification Checklist

Ensure cgi.force_redirect = 1: When using php-cgi with ScriptAlias, keep cgi.force_redirect = 1 enabled in that PHP version’s php.ini so visitors cannot invoke /php74-cgi directly via URL manipulation. Validate Apache Syntax Before Reloading:

sudo apachectl configtest
sudo systemctl reload httpd