| Hi!
Just to let you know that I've made a change to CVS today, reported by Pawel Malachowski, where it looked like the plugins were making too many calls to resolver/DNS when the plugins were compiled with IPv6 options enabled.
This should reduce the occasions of timeouts. However, I do like the idea of making the Nagios server a caching name server too...
Ton On 9 Nov 2006, at 22:25, Steve Shipway wrote: 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
[EMAIL PROTECTED]
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 <[EMAIL PROTECTED]> 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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