timeouts when using secondary dns

[Gerd Mueller]

Hi,

I normaly configure hostaddresses by their ip-adresses. If it's not
possible I always use nscd as very very simple name server cache.

Cheers,

Gerd

 
Am Freitag, den 10.11.2006, 11:25 +1300 schrieb Steve Shipway:
> We dealt with this by installing a local caching-only nameserver on
> the Nagios host itself.  This also took a lot of the load off of the
> main nameservers.   So, resolv.conf was set to use 127.0.0.1 by
> default and have our normal name servers as secondaries.  A nice
> sideeffect was that it vastly sped up the name resolution.
>  
> Steve
>  
> --
> Steve Shipway
> ITSS, University of Auckland
> (09) 3737 599 x 86487
> s.shipway at auckland.ac.nz
> 
> 
> 
>  
> 
>         
>         ______________________________________________________________
>         From: nagios-users-bounces at lists.sourceforge.net
>         [mailto:nagios-users-bounces at lists.sourceforge.net] On Behalf
>         Of stucky
>         Sent: Friday, 10 November 2006 6:57 a.m.
>         To: Az
>         Cc: nagios
>         Subject: Re: [Nagios-users] timeouts when using secondary dns
>         
>         
>         
>         Yey !! That totally did it. Thx AZ I hadn't even considered
>         messing with the resolver cuz I was sure it was a nagios issue
>         so I had to fix nagios.
>         If that wasn't a text book example of how well mailinglists
>         can work then I don't know what is... 
>         
>         thx
>         
>         On 11/7/06, Az <az at whoever.org> wrote: 
>                 stucky wrote:
>                 > I use the check_by_ssh plugin for most of my stuff
>                 and I noticed that
>                 > if the primary nameserver is unavailable nagios
>                 starts freaking out.
>                 > All of a sudden all plugins time out. I tested it
>                 using the 'host' 
>                 > command and it only takes about 1 second longer to
>                 lookup hosts using
>                 > the secondary nameserver.
>                 > The default timeout for check_by_ssh is 10 seconds.
>                 I cranked it up to
>                 > 30 and still I get timeouts. I'm not sure I
>                 understand that one. 
>                 > Has anyone else seen this.
>                 We had a similar issue in that our primary DNS was
>                 doing strange things,
>                 and it quite often took 5 or even 10 seconds to
>                 perform a DNS lookup.
>                 What we were seeing was 70% of service checks (and
>                 subsequently host 
>                 checks) failing by timing out. The key was the
>                 multiple of 5 seconds.
>                 The resolver timeout on, say, RHEL3 is based on
>                 RES_TIMEOUT in
>                 resolv.h... which was 5 seconds.
>                 
>                 We added the following to our resolv.conf , and found
>                 the problems went away:
>                 
>                     options timeout:2 rotate
>                 
>                 This sets the timeout for waiting for a reply to 2
>                 seconds, and tells
>                 the resolve to rotate through your 'nameserver'
>                 entries rather than
>                 always hitting #1, then #2, etc.
>                 
>                 Cheers.
>                 
>                 
>                 
>                 
>         
>         
>         
>         -- 
>         stucky 
> -------------------------------------------------------------------------
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-------------------------------------------------------------------------
Using Tomcat but need to do more? Need to support web services, security?
Get stuff done quickly with pre-integrated technology to make your job easier
Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo
http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642
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