I upgraded and now I can't use my nginx's
proxy_pass arguments on my Ubuntu server to work with PHP. I keep getting
502 Bad Gateway errors. Why is this, and how do I fix this?
According to this LaunchPad Bug and this Debian bug, it was requested that Debian/Ubuntu have
php5-fpm listen on a UNIX socket by default. This was adopted in
5.4.0-rc1, and remains in place in the Ubuntu Quantal (and likely later) packages (this was a package-only change, not an upstream one).
The solution (as outlined in my blog post on this matter) is to change where your
proxy_pass points to, so that it points to
unix:/var/run/php5-fpm.sock which is now the default location for
php5-fpm to set its listener to (this apples to
php5 package versions
5.4.0-rc1 and later in both Ubuntu and Debian at the time of this post, and only to the versions in the main repositories, and not PPAs).
This applies to Ubuntu 12.10 (Quantal Quetzal) and later!