Moving an nginx install from Ubuntu 14.04 to 18.04 and upgrading to more recent versions of nginx, php, php-fpm, I ran into this error in my nginx config:
2020/02/28 04:45:47 [crit] 11784#11784: *1 connect() to unix:/var/run/php7.2-fpm.sock failed (2: No such file or directory) while connecting to upstream, client: 192.168.x.x, server: , request: "GET /index.php HTTP/1.1", upstream: "fastcgi://unix:/var/run/php7.2-fpm.sock:", host: "10.x.x.x"
The “No such file or directory” error is talking about the nginx connection to the php7.2-fpm.sock, rather than the file the GET request is for.
On closer look at where the .sock file is located, this was a subtle error to find and fix, but the fix was simple as I was pointing to the wrong path.
In my nginx default config, I had this line (migrating from a config for an older nginx and pphp-fpm version, this is where it was before):
… I was missing a /php/ dir in the path, so changing to the correct path was the fix: