17 messages in ru.sysoev.nginxRe: Is it possible to monitor the fai...
FromSent OnAttachments
Robbie AllenJun 27, 2008 5:22 pm 
Alexander StauboJun 27, 2008 5:39 pm 
Robbie AllenJun 27, 2008 6:08 pm 
Rt IbmerJun 27, 2008 6:54 pm 
mikeJun 27, 2008 11:02 pm 
Grzegorz NosekJun 28, 2008 4:50 am 
Grzegorz NosekJun 28, 2008 5:31 am 
mikeJun 28, 2008 9:14 am 
Alexander StauboJun 28, 2008 12:28 pm 
Grzegorz NosekJun 28, 2008 12:53 pm 
Almir KaricJun 28, 2008 1:30 pm 
Brice FigureauJun 28, 2008 2:36 pm 
Alexander StauboJun 28, 2008 4:02 pm 
Rt IbmerJun 28, 2008 9:38 pm 
Grzegorz NosekJun 29, 2008 10:57 am.patch, .patch, .patch
Brice FigureauJun 30, 2008 12:23 pm 
Grzegorz NosekJun 30, 2008 12:49 pm 
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Subject:Re: Is it possible to monitor the fair proxy balancer?Actions...
From:Alexander Staubo (alex@public.gmane.org)
Date:Jun 28, 2008 12:28:22 pm
List:ru.sysoev.nginx

On Sat, Jun 28, 2008 at 2:31 PM, Grzegorz Nosek <grze@public.gmane.org> wrote:

However, there still remains the issue of communication between the load balancer and the outside world, i.e. *how* would you like to be told that a backend has been deemed up/down

HAProxy -- apologies for having to mention it again, but it's a useful template -- has a simple status page similar to Nginx's stub status. It comes in HTML and CSV formats, and lists all backends (and frontends) and their status (up, down, going down, going up) and a ton of metrics (current number of connections, number of bytes transfered, error count, retry count, and so on). It can also export the same information on a secure domain socket if you don't want to go through HTTP.

and *how* would you like to tell nginx that backend 1.2.3.4 is currently down?

Pardon me for asking a naive question, but to change the list of backends, would you not simply edit the config file and do a SIGHUP? I would reset whatever internal structures that are kept by the workers, but I can't think of anything that's not okay to lose.

- a new option, e.g. max_requests 10 10 20 20 (specifying the number for each backend in the order of server directives)

That's a horrible syntax and one that is going to cause problems as you add or remove backends from the config. A max_requests setting belongs on each backend declaration.

So, what say you, is such a feature (amounting to returning 502 errors after a certain amount of concurrent requests is reached) generally desired? If so, how would you like to configure it?

You should only return an error if a request cannot be served within a given timeout, not when all backends are full.

Alexander.