webpage check and load balancer weirdness

[Marc Powell]

Neil <mailto:neil-on-nagios at restricted.dyndns.org> wrote:
> Hi Marc,
> 
> So there's nothing we can do on our side?

Sure, investigate the configuration on your load balancing device and
change the load balancing method if you find it lacking.

--
Marc

> 
> Marc Powell writes:
> 
> > Neil <mailto:neil-on-nagios at restricted.dyndns.org> wrote:
> > > Hey guys,
> > > 
> > > Just wondering about the alert I got this morning. I have 8
> > > webservers behind 1 load balancer. One webserver was providing
> > > HTTP internal error 500. I got the alert for that and is correct.
> > > But I also have another check that checks the webpages on the
> > > load balancer. I was wondering why nagios is also seeing the HTTP
> > > 500 error but Internet Explorer gets the proper web pages from
> > > the remaining 7 webservers. Any ideas? 
> > 
> > Depending on the configuration and capabilities of your LB, it may
> > be 
> > using a hash to determine what web server you get sent to. Alteon
> > AD3's do this if your metric is hash. Session persistence is
> > another method. Your first request get's sent to the least utilized
> > web server and all subsequent requests from you get sent to the
> > same device. If your monitoring machine was directed to the bad box
> > on a request then using either method would redirect you to the
> > same box on subsequent requests. You should consult your load
> > balancer's manual and configuration for specifics. 
> > 
> > --
> > Marc




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