PHP-FPM – Resolve open_basedir Not Working with Apache 2.4

The fpm project did a great job allowing the deploy of shared hosting solutions quite easily, even chrooting the users (however, there are some problems with apache that could be solved through symlinking; there are a lot of tutorials on the internet about it).

The solution involving php5-fpm requires mod_fastcgi and allows the hoster to make per-user configurations (memory_limit, max_execution_time... just as an example), and from what I've been able to see, it's pretty stable ;)
About the problems with resolving and using the emails, they're easily solved adding the libraries to the chrooted environment and the executables needed (sendmail for example).

The problem I've found and I'm solving, is about the wrong variables passed to the php scripts by the php-fpm (after chrooting, php-fpm should remove the outside directories, passing to the script only the ones inside the chroot... but it doesn't and something else must take care of that, something like a proxy between mod_fastcgi and php-fpm).
I've managed to solve the problem using a fcgi proxy between php-fpm and apache that automatically corrects the variables, since php-fpm at the time I am writing doesn't manage to fix them.

The prefork MPM has not been the "preferred" MPM for many years.

The reason it is still the default for many distros is that some third-party libraries have trouble with the threading in the worker MPM (which has been the preferred MPM since version 2.2).

Not modules like mod_php, which is quite thread-safe, but libraries used by modules like mod_php, such as mysqli etc.

In 2.4, we have now switched to the STABLE event MPM.

The release is still very new and the documentation has not been completely updated to reflect this.

As has been the case for years, if the prefork MPM is causing you grief, switch to threaded serving and run your dynamic content via fastCGI.