[gentoo-user] /etc/init.d/: ntpd or ntp-client?

[gentoo-user] /etc/init.d/: ntpd or ntp-client?

[Stroller]

Hi there,

I just logged into one of my machines that has recently been powered  
down for a few days - not a terribly common occurrence with my servers  
- to find a date of January 30th showing.

I used to run ntp-client, but AIUI adding this to the default runlevel  
only sets the clock once at boot up. Of course the problem with that  
is that the computer's clock can become inaccurate if the spring  
tension is weak, as is obviously the case in my older PCs.

So a while back I changed /etc/runlevels/default so that ntpd is  
started instead.

I understood that ntpd was not only a server for my LAN (a facility I  
don't use) but that it would also periodically check the time with  
upstream servers & keep the machine's clock in constant sync.

So when I found the clock to be a week out of date I checked that ntpd  
appeared to be running (it was) and restarted it. The date remained  
the same. Stopping ntpd & starting ntp-client corrected the date  
immediately.

Before I do any investigation, can someone tell me if my understanding  
so far is correct? Is ntpd supposed to keep the machine's clock in  
constant sync, or is it only (say) a server to offer the date to  
clients? (depending upon the clock being set correctly by other means)  
I thought I had configured ntpd with upstream servers separately from  
ntp-client.

Stroller.

Re: [gentoo-user] /etc/init.d/: ntpd or ntp-client?

[Justin]

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Stroller schrieb:
> Hi there,
> 
> I just logged into one of my machines that has recently been powered
> down for a few days - not a terribly common occurrence with my servers -
> to find a date of January 30th showing.
> 
> I used to run ntp-client, but AIUI adding this to the default runlevel
> only sets the clock once at boot up. Of course the problem with that is
> that the computer's clock can become inaccurate if the spring tension is
> weak, as is obviously the case in my older PCs.
> 
> So a while back I changed /etc/runlevels/default so that ntpd is started
> instead.
> 
> I understood that ntpd was not only a server for my LAN (a facility I
> don't use) but that it would also periodically check the time with
> upstream servers & keep the machine's clock in constant sync.
> 
> So when I found the clock to be a week out of date I checked that ntpd
> appeared to be running (it was) and restarted it. The date remained the
> same. Stopping ntpd & starting ntp-client corrected the date immediately.
> 
> Before I do any investigation, can someone tell me if my understanding
> so far is correct? Is ntpd supposed to keep the machine's clock in
> constant sync, or is it only (say) a server to offer the date to
> clients? (depending upon the clock being set correctly by other means) I
> thought I had configured ntpd with upstream servers separately from
> ntp-client.
> 
> Stroller.
> 

pkg_postinst() {
	ewarn "You can find an example /etc/ntp.conf in /usr/share/ntp/"
	ewarn "Review /etc/ntp.conf to setup server info."
	ewarn "Review /etc/conf.d/ntpd to setup init.d info."
	echo
	elog "The way ntp sets and maintains your system time has changed."
	elog "Now you can use /etc/init.d/ntp-client to set your time at"
	elog "boot while you can use /etc/init.d/ntpd to maintain your time"
	elog "while your machine runs"


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Re: [gentoo-user] /etc/init.d/: ntpd or ntp-client?

[Stroller]

On 4 Feb 2009, at 13:40, Justin wrote:
> Stroller schrieb:
>> ...
>> I understood that ntpd was not only a server for my LAN (a facility I
>> don't use) but that it would also periodically check the time with
>> upstream servers & keep the machine's clock in constant sync.
>> ...
> pkg_postinst() {
> 	ewarn "You can find an example /etc/ntp.conf in /usr/share/ntp/"
> 	ewarn "Review /etc/ntp.conf to setup server info."
> 	ewarn "Review /etc/conf.d/ntpd to setup init.d info."
> 	echo
> 	elog "The way ntp sets and maintains your system time has changed."
> 	elog "Now you can use /etc/init.d/ntp-client to set your time at"
> 	elog "boot while you can use /etc/init.d/ntpd to maintain your time"
> 	elog "while your machine runs"

Right! That's the very message which caused me to switch!

Stroller.

Re: [gentoo-user] /etc/init.d/: ntpd or ntp-client?

[Justin]

Stroller wrote:
> 
> On 4 Feb 2009, at 13:40, Justin wrote:
>> Stroller schrieb:
>>> ...
>>> I understood that ntpd was not only a server for my LAN (a facility I
>>> don't use) but that it would also periodically check the time with
>>> upstream servers & keep the machine's clock in constant sync.
>>> ...
>> pkg_postinst() {
>>     ewarn "You can find an example /etc/ntp.conf in /usr/share/ntp/"
>>     ewarn "Review /etc/ntp.conf to setup server info."
>>     ewarn "Review /etc/conf.d/ntpd to setup init.d info."
>>     echo
>>     elog "The way ntp sets and maintains your system time has changed."
>>     elog "Now you can use /etc/init.d/ntp-client to set your time at"
>>     elog "boot while you can use /etc/init.d/ntpd to maintain your time"
>>     elog "while your machine runs"
> 
> Right! That's the very message which caused me to switch!
> 
> Stroller.
> 
> 
> 
so use the ntp-client to set the time at boot and use ntp to  keep clock
synced.

Re: [gentoo-user] /etc/init.d/: ntpd or ntp-client?

[Stroller]

On 4 Feb 2009, at 18:23, Justin wrote:
> Stroller wrote:
>>
>> On 4 Feb 2009, at 13:40, Justin wrote:
>>> Stroller schrieb:
>>>> ...
>>>> I understood that ntpd was not only a server for my LAN (a  
>>>> facility I
>>>> don't use) but that it would also periodically check the time with
>>>> upstream servers & keep the machine's clock in constant sync.
>>>> ...
>>> pkg_postinst() {
>>>    ewarn "You can find an example /etc/ntp.conf in /usr/share/ntp/"
>>>    ewarn "Review /etc/ntp.conf to setup server info."
>>>    ewarn "Review /etc/conf.d/ntpd to setup init.d info."
>>>    echo
>>>    elog "The way ntp sets and maintains your system time has  
>>> changed."
>>>    elog "Now you can use /etc/init.d/ntp-client to set your time at"
>>>    elog "boot while you can use /etc/init.d/ntpd to maintain your  
>>> time"
>>>    elog "while your machine runs"
>>
>> Right! That's the very message which caused me to switch!
>>
>> Stroller.
>>
> so use the ntp-client to set the time at boot and use ntp to  keep  
> clock
> synced.

As I said in my post of 4 February 2009 18:20:50 GMT I will do so.

But I had not initially assumed that "maintaining" the time excluded  
the criteria used by ntp-client when setting at boot.

Stroller.

Re: [gentoo-user] /etc/init.d/: ntpd or ntp-client?

[Stroller]

On 4 Feb 2009, at 13:40, Justin wrote:
>
> pkg_postinst() {
> 	ewarn "You can find an example /etc/ntp.conf in /usr/share/ntp/"
> 	ewarn "Review /etc/ntp.conf to setup server info."
> 	ewarn "Review /etc/conf.d/ntpd to setup init.d info."
> 	echo
> 	elog "The way ntp sets and maintains your system time has changed."
> 	elog "Now you can use /etc/init.d/ntp-client to set your time at"
> 	elog "boot while you can use /etc/init.d/ntpd to maintain your time"
> 	elog "while your machine runs"

Except that here, ntp-client seems to start *before* the network, so  
fails to find the ntp-server.

I'll investigate this more later.

Stroller.

Re: [gentoo-user] /etc/init.d/: ntpd or ntp-client?

[Sebastian Günther]

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* Stroller (stroller@stellar.eclipse.co.uk) [14.02.09 08:29]:
>
> On 4 Feb 2009, at 13:40, Justin wrote:
>
> Except that here, ntp-client seems to start *before* the network, so fails 
> to find the ntp-server.
>
> I'll investigate this more later.
>
> Stroller.
>
>
>
If you have baselayout2 and openrc check /etc/rc.conf for the following:

rc_depend_strict="NO"

If you have this, this is your problem...

HTH
Sebastian

-- 
 " Religion ist das Opium des Volkes. "      Karl Marx

 SEB@STI@N GÜNTHER         mailto:samson@guenther-roetgen.de

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Re: [gentoo-user] /etc/init.d/: ntpd or ntp-client?

[Stroller]

On 15 Feb 2009, at 21:51, Sebastian Günther wrote:
> * Stroller (stroller@stellar.eclipse.co.uk) [14.02.09 08:29]:
>>
>> On 4 Feb 2009, at 13:40, Justin wrote:
>>
>> Except that here, ntp-client seems to start *before* the network,  
>> so fails
>> to find the ntp-server.
>>
>> I'll investigate this more later.
>
> If you have baselayout2 and openrc check /etc/rc.conf for the  
> following:
>
> rc_depend_strict="NO"
>
> If you have this, this is your problem...

Nope, sys-apps/baselayout-1.12.11.1 here.

Stroller.

Re: [gentoo-user] /etc/init.d/: ntpd or ntp-client?

[Sebastian Günther]

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* Stroller (stroller@stellar.eclipse.co.uk) [16.02.09 02:10]:
>
> On 15 Feb 2009, at 21:51, Sebastian Günther wrote:
>> * Stroller (stroller@stellar.eclipse.co.uk) [14.02.09 08:29]:
>>>
>>> On 4 Feb 2009, at 13:40, Justin wrote:
>>>
>>> Except that here, ntp-client seems to start *before* the network, so 
>>> fails
>>> to find the ntp-server.
>>>
>>> I'll investigate this more later.
>>
>> If you have baselayout2 and openrc check /etc/rc.conf for the following:
>>
>> rc_depend_strict="NO"
>>
>> If you have this, this is your problem...
>
> Nope, sys-apps/baselayout-1.12.11.1 here.
>

Well in /etc/conf.d/rc iirc should be something similar...

> Stroller.
>
>
Sebastian

-- 
 " Religion ist das Opium des Volkes. "      Karl Marx

 SEB@STI@N GÜNTHER         mailto:samson@guenther-roetgen.de

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Re: [gentoo-user] /etc/init.d/: ntpd or ntp-client?

[Dale]

Stroller wrote:
> Hi there,
>
> I just logged into one of my machines that has recently been powered
> down for a few days - not a terribly common occurrence with my servers
> - to find a date of January 30th showing.
>
> I used to run ntp-client, but AIUI adding this to the default runlevel
> only sets the clock once at boot up. Of course the problem with that
> is that the computer's clock can become inaccurate if the spring
> tension is weak, as is obviously the case in my older PCs.
>
> So a while back I changed /etc/runlevels/default so that ntpd is
> started instead.
>
> I understood that ntpd was not only a server for my LAN (a facility I
> don't use) but that it would also periodically check the time with
> upstream servers & keep the machine's clock in constant sync.
>
> So when I found the clock to be a week out of date I checked that ntpd
> appeared to be running (it was) and restarted it. The date remained
> the same. Stopping ntpd & starting ntp-client corrected the date
> immediately.
>
> Before I do any investigation, can someone tell me if my understanding
> so far is correct? Is ntpd supposed to keep the machine's clock in
> constant sync, or is it only (say) a server to offer the date to
> clients? (depending upon the clock being set correctly by other means)
> I thought I had configured ntpd with upstream servers separately from
> ntp-client.
>
> Stroller.
>
>

I use ntpd here as well.  Ntpd does not set it immediately like other
commands do.  From my understanding ntpd compares its time to a server
then gradually adjusts the clock by speeding up or slowing down the
clock.  It takes a while to do this.  If your clock is a long ways off
then it will take longer.

I'm not sure if this is still true but I read that if it is way off,
several days or longer I would assume, it will require you to adjust it
manually or you could set it with ntpdate which will set it instantly
from one of the time servers.  In this case, set the clock then restart
ntpd.

Hope that helps.

Dale

:-)  :-)

Re: [gentoo-user] /etc/init.d/: ntpd or ntp-client?

[Alan McKinnon]

On Wednesday 04 February 2009 15:38:11 Stroller wrote:
> Before I do any investigation, can someone tell me if my understanding  
> so far is correct? Is ntpd supposed to keep the machine's clock in  
> constant sync, or is it only (say) a server to offer the date to  
> clients? (depending upon the clock being set correctly by other means)  
> I thought I had configured ntpd with upstream servers separately from  
> ntp-client.

ntp is one of those things that looks really easy and turns out to be 
horrendously complicated once you scratch the surface. The problem is not ntp 
itself, it's the subject of time.

ntp is indeed both a server for it's host machine and your LAN, but also a 
client to upstream. It is also full of precautions:

It will not make your clock jump forwards or backwards if your time is way 
out. ntp keeps track of how weak your clock spring is and gradually pulls the 
local clock back into sync with the master clock by making the length of 
seconds fractionally shorter or longer. It does this so that there are no 
gaps in the time record. If it suddenly pulled the clock forward, the time 
tick for midnight might never happen and your crons might not run. I forget 
what the threshold is, but it's not long; and it can take several hours to 
correct a clock that is only a few minutes out.

ntpd is really designed for Unix servers with 3 digit uptimes and clocks not 
assembled by Mickey Mouse's younger brother (which seems to include all pcs 
ever made.....)

Most folk are better off with ntpdate run from a cron. When run, it checks the 
upstream time and immediately corrects the local clock to that time. Schedule 
it for once an hour or so, depending on your bandwidth and local ntp site's 
policies.

-- 
alan dot mckinnon at gmail dot com

Re: [gentoo-user] /etc/init.d/: ntpd or ntp-client?

[Dirk Heinrichs]

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Am Mittwoch, 4. Februar 2009 14:57:28 schrieb Alan McKinnon:

> ntpd is really designed for Unix servers with 3 digit uptimes and clocks
> not assembled by Mickey Mouse's younger brother (which seems to include all
> pcs ever made.....)

Errh, no. It is designed for exactly those machines, so that they are 
independant of their hardware (Mickey Mouse) clock and of course to keep them 
all in sync with each other (and the Unix servers they connect to).

> Most folk are better off with ntpdate run from a cron. When run, it checks
> the upstream time and immediately corrects the local clock to that time.
> Schedule it for once an hour or so, depending on your bandwidth and local
> ntp site's policies.

That does exactly what NTP tries to avoid: Time jumps.

So when you're not connected to the net permanently, one has two choices:

1) Choose one of your machines as the ntp time server which delivers the time 
of its internal clock and synchronize each others time with this one. In the 
end it only matters that the time is correct in _your_ own network, isn't it.

2) If even the most accurate internal clock on your network is not accurate 
enough, plug an accurate time source into one machine you choose as time 
server, then goto 1).

Bye...

	Dirk

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Re: [gentoo-user] /etc/init.d/: ntpd or ntp-client?

[Neil Bothwick]

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On Wed, 4 Feb 2009 13:38:11 +0000, Stroller wrote:

> So when I found the clock to be a week out of date I checked that ntpd  
> appeared to be running (it was) and restarted it. The date remained  
> the same. Stopping ntpd & starting ntp-client corrected the date  
> immediately.

ntpd will not change the time if the difference is too large, the man
page gives the limit. You need to run both at boot; ntp-client sets the
time immediately, no matter what the skew, then ntpd keeps the clock in
time.

-- 
Neil Bothwick

Nymphomania-- an illness you hear about but never encounter.

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Re: [gentoo-user] /etc/init.d/: ntpd or ntp-client?

[Stroller]

On 4 Feb 2009, at 14:11, Neil Bothwick wrote:
> On Wed, 4 Feb 2009 13:38:11 +0000, Stroller wrote:
>
>> So when I found the clock to be a week out of date I checked that  
>> ntpd
>> appeared to be running (it was) and restarted it. The date remained
>> the same. Stopping ntpd & starting ntp-client corrected the date
>> immediately.
>
> ntpd will not change the time if the difference is too large, the man
> page gives the limit. You need to run both at boot; ntp-client sets  
> the
> time immediately, no matter what the skew, then ntpd keeps the clock  
> in
> time.

I see. Many thanks.

I am surprised my clock got so far out of whack, having been only  
switched off a few days. I don't think the battery is completely dead.  
The difference in behaviour seems unexpected, but surely makes sense  
from the developers' point-of-view.

I will set both in the default runlevel & keep an eye on things.

Stroller.

Re: [gentoo-user] /etc/init.d/: ntpd or ntp-client?

[Wolfgang Liebich]

On Wed, Feb 04, 2009 at 06:20:50PM +0000, Stroller wrote:
>
> On 4 Feb 2009, at 14:11, Neil Bothwick wrote:
>> On Wed, 4 Feb 2009 13:38:11 +0000, Stroller wrote:
>>
>>> So when I found the clock to be a week out of date I checked that ntpd
>>> appeared to be running (it was) and restarted it. The date remained
>>> the same. Stopping ntpd & starting ntp-client corrected the date
>>> immediately.
>>
>> ntpd will not change the time if the difference is too large, the man
>> page gives the limit. You need to run both at boot; ntp-client sets the
>> time immediately, no matter what the skew, then ntpd keeps the clock in
>> time.
>
> I see. Many thanks.
>
> I am surprised my clock got so far out of whack, having been only switched 
> off a few days. I don't think the battery is completely dead. The 
> difference in behaviour seems unexpected, but surely makes sense from the 
> developers' point-of-view.
>
> I will set both in the default runlevel & keep an eye on things.
>
> Stroller.

Another method would be using the chrony program (a simpler
alternative to ntp). I've been using it for the last 5+ years, and
consider it a simple and usable program.

Ciao, 
Wolfgang

Re: [gentoo-user] /etc/init.d/: ntpd or ntp-client?

[Drew Tomlinson]

Neil Bothwick wrote:
> On Wed, 4 Feb 2009 13:38:11 +0000, Stroller wrote:
>
>   
>> So when I found the clock to be a week out of date I checked that ntpd  
>> appeared to be running (it was) and restarted it. The date remained  
>> the same. Stopping ntpd & starting ntp-client corrected the date  
>> immediately.
>>     
>
> ntpd will not change the time if the difference is too large, the man
> page gives the limit. You need to run both at boot; ntp-client sets the
> time immediately, no matter what the skew, then ntpd keeps the clock in
> time.
>   

To avoid running ntp-client and ntpd, look at the -g switch for ntpd. 
It will make the big jump once and then keep the clock in sync.

Cheers,

Drew

-- 
Be a Great Magician!
Visit The Alchemist's Warehouse

http://www.alchemistswarehouse.com

Re: [gentoo-user] /etc/init.d/: ntpd or ntp-client?

[Stroller]

On 4 Feb 2009, at 21:29, Drew Tomlinson wrote:
> ...
> To avoid running ntp-client and ntpd, look at the -g switch for ntpd.
> It will make the big jump once and then keep the clock in sync.


So NTPD_OPTS="-g" in /etc/conf.d/ntpd ?

Stroller.

Re: [gentoo-user] /etc/init.d/: ntpd or ntp-client?

[Iain Buchanan]

On Thu, 2009-02-05 at 13:04 +0000, Stroller wrote:
> On 4 Feb 2009, at 21:29, Drew Tomlinson wrote:
> > ...
> > To avoid running ntp-client and ntpd, look at the -g switch for ntpd.
> > It will make the big jump once and then keep the clock in sync.
> 
> 
> So NTPD_OPTS="-g" in /etc/conf.d/ntpd ?
> 
> Stroller.

yep:

       -g, --panicgate
              Allow the first adjustment to be Big.

-- 
Iain Buchanan <iaindb at netspace dot net dot au>

God shows his contempt for wealth by the kind of person he selects to
receive it.
		-- Austin O'Malley