Error 502, phpinfo() directing to 7.4 when 8.1 is installed (File not found)

Question

I'm setting up a web server. I have a freshly installed Ubuntu 22.04, nginx (welcome page works), and php-fpm which installed php8.1 and php-fpm8.1.

To test PHP, I created a /var/www/<my domain>/info.php which just includes:

<?php
phpinfo(); ?>

Browsing to this page gives Error 502 - Bad Gateway.

Checking /var/log/nginx/error.log shows this:

connect() to unix: /var/run/php/php7.4-fpm.sock failed (2: No such file or directory)

I verified that /var/run/php contains php8.1-fpm.sock but indeed not php7.4-fpm.sock

What is causing the request to look for php7.4? How can I fully configure 8.1 so as not to be reliant on old/multiple versions of php?

Answer 1

You need to configure the path of the fpm php module to use in /etc/nginx/sites-available/default config file:

location ~ \.php$ {
    ...
    # Nginx php-fpm sock config:
    fastcgi_pass unix:/run/php/php8.1-fpm.sock;
    ...
}

So edit "/etc/nginx/sites-available/default" and change from

fastcgi_pass unix:/run/php/php7.4-fpm.sock;

to

fastcgi_pass unix:/run/php/php8.1-fpm.sock;

and restart nginx