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<div class="moz-cite-prefix"> For general amusement and perhaps
education, the NTP problem of choosing amongst competing time
givers is known as the Byzantine Generals Problem. The situation
is a group of Generals/time givers offer their views, but some may
not be truthful (are traitors) and ought to be excluded from the
group. The first step in a solution is to form a majority group (a
quorum, a concensus), and for that there needs to be 2N+1
participants to caste out N possible non-truthful members. Then
stratum number and optionally other measurements come into play.
Thus for us we ought to have an odd number of time givers, a
minimum of three and a few more than that can be better.<br>
Including the PC local clock amongst them biases matters if
the local clock is far off the mark. It's presence is in case
there are no other time givers for this machine (network problems)
and yet this machine may offer time to other machines. Oh dear,
that's an awkward situation if the local clock may be well off,
which in turn can upset a site. To minimize the problem of
possibly insane local machine clock sources have each machine
reference a set of likely external sources located both on-site
and remotely (forms overlapping meshes). Friends helping friends
based on widely spread expertise. <br>
The Byzantine Generals problem arises in many kinds of
fault-tolerant systems.<br>
Thanks,<br>
Joe D.<br>
<br>
On 28/01/2018 11:37, Bernd Eckenfels wrote:<br>
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<p class="MsoNormal">Hello,</p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I think the Problem here is that chrony is
not part of the minimal System, at least it is not installed
after the Installation and I dont see the package on the
Installer-DVD1.</p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">The NTP Option in the installer is not only
a one shot Option (which seems to work) but it also offers a
checkbox to start the daemon. I had selected that one. The
chrony config file is written with the pool entry. </p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">(I pretty much prefer chrony over ntpd, it
producs less Problems with time warping on customer systems,
so it would be good to make it a essential package. Glad that
SuSE catched up here)</p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Gruss</p>
<p class="MsoNormal">Bernd</p>
<p class="MsoNormal">-- <br>
<a class="moz-txt-link-freetext" href="http://bernd.eckenfels.net">http://bernd.eckenfels.net</a></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal" style="border:none;padding:0cm"><b>Von: </b><a
href="mailto:jrd@netlab1.net" moz-do-not-send="true">Joe
Doupnik</a><br>
<b>Gesendet: </b>Sonntag, 28. Januar 2018 12:16<br>
<b>An: </b><a href="mailto:sle-beta@lists.suse.com"
moz-do-not-send="true">sle-beta@lists.suse.com</a><br>
<b>Betreff: </b>Re: [sle-beta] beta5: Cannot adjust 'NTP'
service when NTP wasenabled in installer</p>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"> There is also the step of going into
systemd services and enabling service NTP, at least in my
experiments.<br>
In the overall time keeping mix are two client-style
competitors. It seems to me, as some say, the wise choice
would be use regular NTP itself which can be both client and
server, under our control. This also avoids the mistake of
force jumping clocks which are out of synchronization, an act
which can clobber cron jobs and other time sensitive things.
The initial setting of the local machine's time is properly
done by adding tag "iburst" to a server line within
/etc/ntp.conf. such as server uk.pool.ntp.org iburst. That
causes rapid slewing, rather than the normal more gradual one
and has no jumps.<br>
Nuances about choosing a time source amongst competitors
is another soft spot best left to the seasoned solutions of
NTP proper. That puzzle has been worked out over many years
through much experience with the protocol. Another thing to do
in most cases is turn off using the local clock as a time
source competitor (meaning comment out the lines in
/etc/ntp.conf saying server 127.127.1.0 and fudge
127.127.1.0 stratum 10).<br>
Thanks,<br>
Joe D.<br>
<br>
On 28/01/2018 00:31, Bernd wrote:<o:p></o:p></p>
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<div>
<p class="MsoNormal" style="margin-bottom:12.0pt">Hello,<br>
<br>
If I install beta5 with no registration/packages and
select under settings to get the time from the NTP
pool the screen with the timezone map shows me the
right (updated) time.<br>
<br>
But if I proceed with the installation the
"Performing Installation" screen (Step: "Save
Installation Settings" -> "Writing NTP
Configuration...") shows a popup "Cannot adjust
'NTP' service.". This popup does not happen when I
do not enable NTP. When clicking OK the installation
proceeds.<o:p></o:p></p>
</div>
<p class="MsoNormal">Gruss<o:p></o:p></p>
</div>
<p class="MsoNormal" style="margin-bottom:12.0pt">Bernd<o:p></o:p></p>
</div>
<p class="MsoNormal">PS: in the timezone selection the
"hardware clock in UTC" does not adjust the currently
displayed time. It is a bit frustrating when you select a
timezone and the displayed current time is off by an hour.
Because you have to switch on the UTC mode and then go to
manual settings and correct the time (or turn on NTP as I
did). I think former versions of SLES has that "feature"
as well.<o:p></o:p></p>
</div>
<p class="MsoNormal"><br>
<br>
<br>
<o:p></o:p></p>
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