[...] As I'm not a completely negative guy ;-) I propose a more general solution to monitor Nginx cleanly and to do whatever your want.

Just need to create a shared memory area named nginx for example and put data as in the /proc filesystem. It's like stub_status module but using shared memory instead of HTTP. In the case of upstream servers status writing on shared memory during a state change (down/up) has no significant cost.

The script/agent will just read the shared memory and act according to data.

The bad thing is that the nagios and collectd plugins will need a rewrite!

I've used this technique on a mission critical application (40 processes, ~ 700 threads) running on an AIX box, it was useful to collect statistics and benchmark data without stressing the system.

So Dear List, what do you think?