# Re: Is it possible to monitor the fair proxy balancer?

**URL:** <https://www.ruby-forum.com/t/re-is-it-possible-to-monitor-the-fair-proxy-balancer/141671>\
**Category:** NGINX\
**Created:** [June 28, 2008, 11:45pm UTC](https://www.ruby-forum.com/t/re-is-it-possible-to-monitor-the-fair-proxy-balancer/141671 "2008-06-28T23:45:50Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Brice\_F](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/f17d59/32.png) [@Brice\_F](https://www.ruby-forum.com/u/Brice_F)\
**Post date:** [June 28, 2008, 11:45pm UTC](https://www.ruby-forum.com/t/re-is-it-possible-to-monitor-the-fair-proxy-balancer/141671/1 "2008-06-28T23:45:50Z")

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On Sat, June 28, 2008 13:51, Grzegorz N. wrote:

> slightly overkill.  
> I think we could all (I mean mainly module authors) benefits from an  
> nginx  
> API (like the configuration system) to declare centrally  
> counters/variables of each module that in turn could be displayed by the  
> status module. If I have some spare time soon, I’ll try to produce an  
> nginx patch to implement this.

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**Author:** ![Brice\_F](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/f17d59/32.png) [@Brice\_F](https://www.ruby-forum.com/u/Brice_F)\
**Post date:** [June 29, 2008, 6:49am UTC](https://www.ruby-forum.com/t/re-is-it-possible-to-monitor-the-fair-proxy-balancer/141671/2 "2008-06-29T06:49:06Z")

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> status module. If I have some spare time soon, I’ll try  
> to produce an  
> nginx patch to implement this.

Excellent indeed! At the most basic level it would be extremely useful  
if nginx could signal an external process once it declared one of the  
upstream servers offline (based on the timeout configs in its main conf  
file).

My intention from such a thing would be to receive an email letting me  
know ‘oh no upstream xyz is down!!’ and ‘oh good, upstream xyz is back  
online’.

Some people have argued that such a thing should be left to external  
monitoring tools like heartbeat etc. However such monitoring is no where  
near the same IMO. For instance, heartbeat could see the upstream as up  
because it is alive and pingable, but it wouldn’t be aware if nginx  
declared it as offline due to timeouts or 500 errors (again, based on  
settings in its conf file)!!

Thanks!

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**Author:** ![Brice\_F](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/f17d59/32.png) [@Brice\_F](https://www.ruby-forum.com/u/Brice_F)\
**Post date:** [June 29, 2008, 8:08pm UTC](https://www.ruby-forum.com/t/re-is-it-possible-to-monitor-the-fair-proxy-balancer/141671/3 "2008-06-29T20:08:55Z")

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Hi,

On sob, cze 28, 2008 at 11:36:51 +0200, Brice F. wrote:

> I think we could all (I mean mainly module authors) benefits from an nginx  
> API (like the configuration system) to declare centrally  
> counters/variables of each module that in turn could be displayed by the  
> status module. If I have some spare time soon, I’ll try to produce an  
> nginx patch to implement this.

I have attached an experimental patchset for pluggable status reports  
for nginx HTTP modules plus initial upstream\_fair support.

The patchset is rather ugly because it requires adding a field to every  
HTTP  
module definition, thus breaking 3rd party modules. However, the  
required changes are trivial (as you can see in the patch).

I considered adding support for all modules (not only HTTP ones) and  
changing the ngx\_module\_t structure instead (which has some room to  
spare and would only require a few macro changes) but I think it’s up to  
Igor to decide.

Please have a look and let me know what you think.

Best regards,  
Grzegorz N.