Rt Ibmer <rtibmx@...> writes:

modify and what types of system calls I should look at? Maybe all I need to do is find the spot where nginx deems it should skip a downed server, and immediately after that add this code:

You should look at the file:

nginx/src/http/ngx_http_upstream_round_robin.c

goes here", NULL);

It's not as easy to do.

product? I would not want to have to keep applying my own patch every time I compile a new version of nginx and am happy to contribute my work to this excellent product and project. Thank you.

Well, from my point of view your solution is not good engineering and not in the spirit of Nginx. I understand your need but good supervision and monitoring is what is needed. I don't believe Igor is likely to call fork() to execute a script in response to an event in its code.

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?