<HTML><BODY style="word-wrap: break-word; -khtml-nbsp-mode: space; -khtml-line-break: after-white-space; ">Hi!<DIV><BR class="khtml-block-placeholder"></DIV><DIV>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.<DIV><BR class="khtml-block-placeholder"></DIV><DIV>This should reduce the occasions of timeouts. However, I do like the idea of making the Nagios server a caching name server too...<DIV><BR class="khtml-block-placeholder"></DIV><DIV>Ton</DIV><DIV><BR><DIV><DIV>On 9 Nov 2006, at 22:25, Steve Shipway wrote:</DIV><BR class="Apple-interchange-newline"><BLOCKQUOTE type="cite"> <DIV dir="ltr" align="left"><FONT face="Arial" color="#0000ff" size="2"><SPAN class="196462322-09112006">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.</SPAN></FONT></DIV> <DIV dir="ltr" align="left"><FONT face="Arial" color="#0000ff" size="2"><SPAN class="196462322-09112006"></SPAN></FONT> </DIV> <DIV dir="ltr" align="left"><FONT face="Arial" color="#0000ff" size="2"><SPAN class="196462322-09112006">Steve</SPAN></FONT></DIV> <DIV> </DIV><P><FONT size="2">--<BR>Steve Shipway<BR>ITSS, University of Auckland<BR>(09) 3737 599 x 86487<BR><A href="mailto:s.shipway@auckland.ac.nz">s.shipway@auckland.ac.nz</A><BR><BR></FONT></P> <DIV> </DIV><BR> <BLOCKQUOTE style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #0000ff 2px solid; MARGIN-RIGHT: 0px"> <DIV class="OutlookMessageHeader" lang="en-us" dir="ltr" align="left"> <HR tabindex="-1"> <FONT face="Tahoma" size="2"><B>From:</B> nagios-users-bounces@lists.sourceforge.net [<A href="mailto:nagios-users-bounces@lists.sourceforge.net">mailto:nagios-users-bounces@lists.sourceforge.net</A>] <B>On Behalf Of </B>stucky<BR><B>Sent:</B> Friday, 10 November 2006 6:57 a.m.<BR><B>To:</B> Az<BR><B>Cc:</B> nagios<BR><B>Subject:</B> Re: [Nagios-users] timeouts when using secondary dns<BR></FONT><BR></DIV> <DIV></DIV>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.<BR>If that wasn't a text book example of how well mailinglists can work then I don't know what is... <BR><BR>thx<BR><BR> <DIV><SPAN class="gmail_quote">On 11/7/06, <B class="gmail_sendername">Az</B> <<A href="mailto:az@whoever.org">az@whoever.org</A>> wrote:</SPAN> <BLOCKQUOTE class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0pt 0pt 0pt 0.8ex; BORDER-LEFT: rgb(204,204,204) 1px solid">stucky wrote:<BR>> I use the check_by_ssh plugin for most of my stuff and I noticed that<BR>> if the primary nameserver is unavailable nagios starts freaking out.<BR>> All of a sudden all plugins time out. I tested it using the 'host' <BR>> command and it only takes about 1 second longer to lookup hosts using<BR>> the secondary nameserver.<BR>> The default timeout for check_by_ssh is 10 seconds. I cranked it up to<BR>> 30 and still I get timeouts. I'm not sure I understand that one. <BR>> Has anyone else seen this.<BR>We had a similar issue in that our primary DNS was doing strange things,<BR>and it quite often took 5 or even 10 seconds to perform a DNS lookup.<BR>What we were seeing was 70% of service checks (and subsequently host <BR>checks) failing by timing out. The key was the multiple of 5 seconds.<BR>The resolver timeout on, say, RHEL3 is based on RES_TIMEOUT in<BR>resolv.h... which was 5 seconds.<BR><BR>We added the following to our resolv.conf , and found the problems went away:<BR><BR> options timeout:2 rotate<BR><BR>This sets the timeout for waiting for a reply to 2 seconds, and tells<BR>the resolve to rotate through your 'nameserver' entries rather than<BR>always hitting #1, then #2, etc.<BR><BR>Cheers.<BR><BR><BR><BR><BR></BLOCKQUOTE></DIV><BR><BR clear="all"><BR>-- <BR>stucky </BLOCKQUOTE><BR><BR><P align="center">This message has been scanned for viruses by <A href="http://www.MailController.altohiway.com/">MailController</A>.</P><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">-------------------------------------------------------------------------</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Using Tomcat but need to do more? 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