Monitoring a matrix of load-balanced VirtualHosts?

[Andreas Ericsson]

JB Segal wrote:
> On 8/29/05, Marc Powell <marc at ena.com> wrote:
> 
>>
>>>-----Original Message-----
>>>From: nagios-users-admin at lists.sourceforge.net [mailto:nagios-users-
>>>admin at lists.sourceforge.net] On Behalf Of JB Segal
>>>Sent: Monday, August 29, 2005 3:09 PM
>>>To: Nagios-users at lists.sourceforge.net
>>>Subject: [Nagios-users] Monitoring a matrix of load-balanced
>>
>>VirtualHosts?
>>
>>>Hi. I've searched through the archives, the nagiosexchange site, and
>>>google in general, but have yet to find a satisfactory answer to this:
>>>
>>>I'm running (ok, my employer is running and has been for a while now)
>>>1.2, talking to a variety of machines running various vintages of
>>>RedHat and various versions of nrpe and the plugins package.
>>>
>>>I have a series of web servers - call them A, B and C - which are
>>>running apache, which is serving a variety of VirtualHosts - let's
>>>call them foo.com, bar.com and baz.com.
>>>
>>>Each machine responds to both www.(foo|bar|baz).com and
>>>{hostname}.(foo|bar|baz).com (say: A.foo.com)
>>>
>>>I need to check each server for the aliveness of each VHost.
>>>
>>>I really am not sure how best to do this. Ok, I'm not really sure how
>>>to do this in any sort of clean fashion.
>>>
>>>I would expect this to be a common need, but I seem to be wrong.
>>>
>>>Help, Advice, Pointers to things I missed in TFM, etc. all welcome.
>>
>>Perhaps I'm misunderstanding, but have you looked at check_http? It
>>should be able to easily handle what you want using the -H, -I, -e and
>>possibly -u arguments. Each machine would have at least 3 (or 6 if you
>>want to also check host.foo.com) services associated with it;
>>Website_foo.com, Website_bar.com and Website_baz.com, each of which uses
>>check_http to verify the site is active and returning content you
>>expect.
>>
>>--
>>Marc
> 
> 
> To start with, thanks for responding.
> 
> 2nd: I left out from my 1st mail the fact that I'd really really
> prefer to do this in as few cfg stanzas as possible, as 1) I'd like
> this solution to scale if, say, we were to end up with 20 webservers
> and 45 domains - I /do/ have to check host.foo.com per boss's reqests
> - so I'd love to not have to add another {number of websites} stanzas
> for each new server.
> 2) I just cleaned up the previous admin's installation and reduced
> 3000 lines of cfg to 800 lines, and I'd love to not have to expand
> back to that again right now.
> 
> So, not to sound like a complete idiot - but probably unable to avoid
> it, I continue my query:
> 
> I've spent a while (before I sent my 1st mail, even) staring at the
> check_http -h output and being... nonplussed. Unfortunately, that's
> been my response to most of the nagios docs.
> 

With 1.2 your best bet would probably be to write a wrapper script that 
checks all the vhosts. check_http and some clever sed'ing should do the 
trick, really. With 2.0 you can assign services to hostgroups (I'm not 
sure that worked in 1.2...)

> Your response puzzles me even more, by implying that the '-u' might be optional.
> 

It is. If it's not specified, the url requested is '/'.

-- 
Andreas Ericsson                   andreas.ericsson at op5.se
OP5 AB                             www.op5.se
Lead Developer


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