Nginx and/or php5-fpm remembers symlinked root directory

Question

My nginx site root points to a symlink. If I alter the symlink (aka deploy a new version of the website) the old version of the php script keeps showing up. That smells like cache, or a bug.

First it looked like Nginx was caching the symlinked dir, but reloading/restarting/killing and starting nginx didn't fix it, so I restarted php5-fpm - this fix my issue.

But I dont want to restart nginx and/or php5-fpm after a deploy - I want to know why there is such a cache (or bug), and why it didn't work properly.

Usefull information:

• OS: Ubuntu 13.10 (GNU/Linux 3.8.0-19-generic x86_64)
• Nginx: via ppa:nginx/stable
• PHP: via ppa:ondrej/php5 (php5-fpm)

Nginx site config:

root /home/rob/sandbox/deploy/public/; index index.php index.html index.htm; location / {     try_files $uri $uri/ /index.php?$args; } location ~ \.php$ {     try_files $uri =404;     fastcgi_split_path_info ^(.+\.php)(/.+)$;     include fastcgi_params;     fastcgi_index index.php;     fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;     fastcgi_pass php; } 

Nginx server config (partly, rest is default):

http {     sendfile off;     upstream php {         server unix:/var/run/php5-fpm.sock;     } } 

Tree for /home/rob/sandbox:

├── deploy -> web2 ├── web1 │   └── public │       └── index.php (echo ONE) └── web2     └── public         └── index.php (echo TWO) 

• request: http://localhost/index.php
• expected response: TWO
• actual response: ONE

Part of the output from realpath_cache_get()

[/home/rob/sandbox/deploy/public/index.php] => Array (     [key] => 1.4538996210143E+19     [is_dir] =>      [realpath] => /home/rob/sandbox/web2/public/index.php     [expires] => 1383730041 ) 

So this means deploy/public/index.php is properly linked to web2/public/index.php, right? Well, even with the correct paths in the realpath_cache list, the respone still is ONE.

After rm deploy and ln -s web2 deploy Nginx was restarted, no effect. Restarting php5-fpm after this gives the expected response of 'TWO'.

It's good to know that beside the index.php files, I did some test with .css and .js files. After removing and recreating the symlink from/to web1 and web2, nginx will respond with the correct contents of the files.

What did I miss, what am I not seeing?

Answer 1

Configure your nginx using $realpath_root. It should help.

fastcgi_param SCRIPT_FILENAME $realpath_root$fastcgi_script_name; fastcgi_param DOCUMENT_ROOT $realpath_root; 

Kudos go to Vitaly Chirkov (https://stackoverflow.com/a/23904770/219272).

Answer 2

Once I altered the realpath_cache_ttl to '2' (That should fix it) the incorrect content was still showing.

After some digging in the loaded mods for php-fpm, I discovered that opcache was up and running. Disabling that will clear the cached realpath's when the ttl is over.

I don't wanna lower the realpath cache ttl to much,so I will settle in with a reload of php-fpm, since it is graceful. I hope this thread and my answers will help others ;)