[Nagiosplug-devel] [ nagiosplug-Feature Requests-1703823 ] [check_ntp] add option to verify stratum
John P. Rouillard
rouilj at cs.umb.edu
Fri Apr 20 06:00:59 CEST 2007
In message <E1HejAy-0007Dt-B4 at sc8-sf-web21.sourceforge.net>,
"SourceForge.net" writes:
>Submitted By: Enrico Scholz (ensc)
>>Assigned to: Thomas Guyot (dermoth)
>Initial Comment:
>Please add an option which checks whether stratum of server exceeds a
>certain value.
>
>----------------------------------------------------------------------
>
>>Comment By: Thomas Guyot (dermoth)
>Date: 2007-04-19 22:48
>
>Message:
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>user_id=375623
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>
>That would be fairly easy now that i know that much about check_ntp and
>can be interesting in many scenarios :)
I enhanced the original check_ntp script quite a while ago becuse it
was monitoring things incorrectly according to my understanding of
ntp.
My stratum check accepts a range that the synchronization peer must be
at. So -s 2:3 means that the sync peer host must be at 2 or 3. It
returns a warning if the host is lower or higher then it should be.
Also I think you already test warning and critical levels for the
jitter of the sys.peer (or pps.peer), but I added
-C (--candidates)
Check number of backup servers that are capable of becoming
peers. Range (min:max), solo number is minimum number.
If you look at the output of ntpq -p, this counts the number of * and +
hosts that are available. E.G in this case:
remote refid st t when poll reach delay offset jitter
==============================================================================
*ntp1 66.187.233.4 2 u 937 1024 377 0.393 -1.660 0.444
+ntp2 192.5.41.209 2 u 470 1024 377 9.619 4.526 1.559
+ntp3 195.66.241.10 2 u 645 1024 377 47.782 -1.140 0.382
ntp4 193.5.41.209 2 u 470 1024 377 9.619 18.526 25.559
LOCAL(0) LOCAL(0) 10 l 61 64 377 0.000 0.000 0.004
would compare 3 to the range specified by -C. This is useful for
detecting peers that have lost synchronization leaving you vulnerable
to a timeshift due to lack of other peers to stabilize the algorithm.
Also
-F (--falseticker)
Check the number of falsetickers reported. Range (min:max).
so -F 0:2 means I will accept up to 2 falsetickers connected to my ntp
server. Good for detecting broken time sync sources.
Also I implemented:
-l (--last) Maximum time (seconds) between packets received
from polled machines.
This is compared against the "when" column in the ntpq output to look
for ntp servers that are unresponsive, down, or unreachable due to
network issues.
If you want you can use some/all of these ideas in your check_ntp
implementation.
-- rouilj
John Rouillard
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