Cam wrote:
Hello list,
I've been alternately reading the NTP documentation and banging my
head on the desk, so please excuse any intemperance and/or incoherence.
I'm glad my car's manual wasn't written by the same people who wrote
the NTP documentation or it would start with an exhaustive treatment
of the carnot cycle and then roar off into advanced thermodynamics
when all I wanted to know was how often to change the d**n oil. Pauses
to bang head on desk several more times. Apparently the idea of
starting with simple examples ("hello world") and working up to
complex examples ("program to prove the four-color theorem") didn't
occur to them; they want to prove the theorem right away.
But I digress. I have a computer, lets call it MASTER, which has time
of day that I'm happy with. I have a bunch of other computers, all on
the same subnet, and I want them to set their clocks to match MASTER.
That's it. Sounds like the making of a real simple example. I believe
this can be done because the NTP pages make reference to an
"Undisciplined Local Clock" but as with all the documentation it
assumes you are already an expert so no simple example is given. Whack
whack.
So, finally, the question is: Does anybody have a link to a web page
that gives some simple examples (eg "to sync from machine 1.2.3.4 do
this", "to setup a local undiciplined server do that")? If so it would
be greatly appreciated.
Thanks
Cam Farnell
ps I've already R'd the F'ing M or at least made a serious attempt at
it. I don't want to know every arcane detail of NTP in the known
universe; I want to set up a *really* simple system.
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Install ntpd on all computers involved. How is left as an exercise for
the student.
On MASTER, create /etc/ntp.conf. It should contain, at a minimum:
#
# Declare the local clock to be the clock of last resort.
# It will be used to serve time in the absence of any other.
#
server 127.127.1.0 # Local clock, unit 0
fudge 127.127.1.0 stratum 10
On the clients, create /etc/ntp.conf containing:
server MASTER
YOU will be responsible for keeping the time on MASTER correct!
MASTER's clock WILL drift. It may drift badly. YOU must check the time
periodically and adjust MASTER's clock. The clients should stay in
synch with MASTER. If, after a couple of months of neglect, you find
that all the clocks are 27 minutes slow, you have no one to blame but
yourself. YOU HAVE BEEN WARNED!!!! If you have to make large
corrections the clients will take a long time to catch up. If you have
to make a correction greater than 1024 seconds (about 17 minutes) all
the ntpd on all the clients will panic and exit.
The above is a bare bones (well gnawed) configuration that no right
thinking person would tolerate but it should work.
Far better would be to have MASTER served by either four internet
servers, or a hardware reference clock (GPS timing receiver, WWV
receiver, WWVB receiver, CHU receiver, etc.) That should not only keep
everybody synched up but also provide time correct to within 10
milliseconds or better.
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