How to Configure Multiple PHP Versions on a Single VPS Server

Have you tried running various PHP websites on a single VPS server and thought to yourself, "Why does each project need a different version of PHP?" I have. But once you understand how to run multiple versions of PHP on a single VPS, it's much easier. Let's talk about it as though two buddies are troubleshooting a tech problem together.

Why Do You Need More Than One PHP Version​

I keep asking the question, "Why does some web project need old PHP 7.4 while the new web app needs PHP 8.2?" But it is how it goes in the web project world. It is better to run both PHP versions than to force one version, and something breaks.

You might need to run multiple PHP versions in the context of:

• Running tests of new features safely
• Supporting old legacy websites that are running fine
• Running new frameworks that just need PHP 8+

Makes sense right?

How to Install Multiple PHP Versions with Ease​

You can install many PHP versions side by side with little hassle.

The simple plan is as follows:

• Add PHP repository.
• Install the desired PHP versions
• Tell each website which PHP version to use

It is a great feeling when everything works out of the box, isn’t it?

PHP-FPM for Each Version​

Each PHP version has its own PHP-FPM service, and you can create new pools for each site.

I typically create files that look like:

• /etc/php/7.4/fpm/pool.d/site1.conf
• /etc/php/8.2/fpm/pool.d/site2.conf

Then I assign each pool to a different port:

• Site 1 - 127.0.0.1:9074
• Site 2 - 127.0.0.1:9082

Now, each site is using the appropriate version of PHP. Simple and clean.

Connecting PHP with Nginx or Apache​

This step is what determines whether your VPS runs smoothly or acts up.

With Nginx

In the server block, I would write:

fastcgi_pass 127.0.0.1:9082;

This indicates to Nginx to operate on PHP 8.2 for that site.

With Apache

Apache can utilize either SetHandler or proxy_fcgi. You will just need to match the correct port or socket. If you accidentally select the incorrect version, the site generally just breaks in unexpected ways. Believe me, I have done it.

Tips to Keep Everything Nice and What I Like to Call – Organized​

Here is a list of small, but strong habits to keep:

• Good naming of each PHP-FPM pool
• Keep config files separate
• Use service restart for any change
• Know what site is using what PHP version

These little actions save you a lot of confusion in the future.