How to monitor HTTP response error codes from nginx using munin?

Solution 1:

Well, no such animal existed, so I conjured it.

You'll find the latest code in the gist. Enjoy.

Solution 2:

I am not aware of any out-of-box OSS solutions. I personally wrote this kind of plugin, but cannot share the code. It's two stage:

1. Log parser to collect fresh statistics (like tail -f). Since you can define Nginx log format, you are free to log the values you want, e.g. status code, upstream request time, etc.
2. Munin plugin to report the statistics to Munin.

You will have to share the state between these two parts. There is a handful of choices: in memory (my implementation of log parser was event-driven daemon storing all the statistics in memory); MongoDB; Redis; traditionaly MySQL; shared memory; etc.