[Xymon] BUG: ntpdate command used in Xymon takes 2+ seconds each in RHEL 7 (with ntp 4.2.6+)

Matt Vander Werf mvanderw at nd.edu
Fri Sep 25 15:07:55 CEST 2015


Any response to this e-mail? Just wanted to make sure it wasn't missed....

I'm currently unable to utilize the ntp test functionality in Xymon as much
as I would really like to (as it causes xymonnet to go over the 5 minute
interval time) and won't be able to until this issue is addressed in an
upstream fix and release AND a Terabithia RPM release, as I am using
Terabithia RPMs for my Xymon server, or at the very least a patch for the
xymonnet binary that I'm using. If it'd be easier and possible to just
release a new Terabithia RPM for (at least) RHEL 7, that would work
too....but I understand if there is the desire to keep the RPMs and
upstream versions the same.

I understand that most people aren't having this issue, as they are using
an upstream ntp version below 4.2.6, but any future OS releases that use
ntp >= 4.2.6 will have this same issue (including all new RHEL releases)!

Would greatly appreciate a fix for this issue ASAP, or at the very least an
acknowledgment of this issue and that a fix will be released soon!

Thanks very much!!

Matt Vander Werf

On Fri, Sep 18, 2015 at 9:26 AM, Matt Vander Werf <mvanderw at nd.edu> wrote:

> Hello J.C., etc.
> (Brief Summary)
> I noticed a issue/bug in the way Xymon uses the ntpdate command for it's
> built-in ntp checks. Each ntp test (using the ntpdate options hard-coded
> into Xymon) takes >= 2 seconds to run in any OS that uses upstream ntp
> version 4.2.6 or later, including RHEL 7. This is due to a 2 second delay
> that was put in place in upstream ntp starting with version 4.2.6. While
> RHEL 6 uses upstream ntp 4.2.6 in it's latest iteration, the behavior I'm
> referring to was reverted by Red Hat when RHEL 6 moved from using version
> 4.2.4 to 4.2.6 in a minor release. This was because this kind of major
> change in behavior was not desired in only a minor RHEL release. However,
> in RHEL 7 it was acceptable to keep this behavior change in place since it
> was a major OS release.
> (Detailed (continued) Summary)
> Initially, I thought it was a Red Hat issue, so a support ticket was
> opened up with Red Hat to figure out what the issue was. The support person
> was able to replicate the issue I was seeing and created a public Bugzilla
> bug here: https://bugzilla.redhat.com/show_bug.cgi?id=1260140. The ntp
> package maintainer for Red Hat replied saying this was intended behavior
> and while reverted in RHEL 6, it would not be reverted in RHEL 7. I asked
> in the support ticket why it was not going to be fixed in RHEL 7 and got
> this response in the support ticket:
> "The original ntp version shipped in RHEL6 was 4.2.4, which had ntpdate
> that was fast, but violated the default 2s minimum spacing between
> requests. An NTP server with enabled rate limiting would not respond more
> than once to such client. In ntp 4.2.6 that bug was fixed by adding spacing
> between the requests, which slows down the ntpdate operation. This change
> in behavior was not acceptable for a minor RHEL6 release, so the bug was
> restored in a patch. In RHEL7 as a new major release I think such change is
> acceptable and ntpdate now works as upstream intended."
> Please see public Bugzilla bug for additional links for reference of this
> change in behavior.
> (Request)
> *It would be greatly appreciated if this could be fixed in upstream Xymon
> ASAP! However, since my Xymon server was installed using Terabithia RPMs,
> what is most important to me is to get an updated Terabithia RPM created
> that I can use to update my Xymon server. I understand that a source code
> patch has already been created for Debian Xymon here:
> https://anonscm.debian.org/cgit/collab-maint/xymon.git/tree/debian/patches/workaround-changed-ntpdate-behaviour
> (referenced in earlier mailing list post:
> http://lists.xymon.com/pipermail/xymon/2015-September/042224.html). This
> would work perfectly!!
> However, since I am using Terabithia RPMs, it is not very easy to simply
> apply this above patch and recompile the base source code and use that,
> since I am I not using just the base source code.
> Maybe a hotfix release of Xymon could be created and released sometime
> very soon with this fix? Currently, I am unable to do all the ntp tests I
> would like to do because it causes xymonnet to go over the 5 minute
> interval time!....
> In the meantime, would it be possible for someone (maybe J.C.) to create a
> binary patch or something that I could apply to the current xymonnet binary
> with the fix in the above patch? Just a thought...and would be extremely
> appreciated!!
> Thank you very much for your time and work you do to make Xymon a great
> monitoring tool! I look forward to some fixes being applied to resolve this
> issue with the ntp tests!
> TL;DR:
> ntp checks take WAY to long in Xymon using hard-coded ntpdate options, due
> to change in ntpdate behavior starting in upstream ntp version 4.2.6. This
> particularly affects Xymon servers running on RHEL 7 (and new releases in
> the future). Hotfix needed in Xymon to fix this issue (see source code
> patch above) ASAP! If possible, a binary patch to xymonnet binary would be
> much preferred in the meantime! I am using Terabithia RPMs for my Xymon
> server, so using above source code patch is not possible or desirable!
> FYI: I am running Xymon 4.3.21-4.el7.terabithia for my Xymon server.
> Thanks!!
> --
> Matt Vander Werf
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