Ubuntu
ntp package

Confusing comments in /etc/default/ntpdate

Bug #537451 reported by Hans-Peter on 2010-03-11

This bug affects 2 people

Affects		Status	Importance	Assigned to	Milestone
	Ubuntu Server papercuts	Won't Fix	Low	Dave Walker	Ubuntu Server papercuts maverick-beta
	ntp (Ubuntu)	Won't Fix	Wishlist	Unassigned

Bug Description

Binary package hint: ntpdate

Not sure, if this is a bug at all, but i see strange things. Fact is, system clock was totally wrong (about half an hour). Calling ntpdate with ntp.ubuntu.com as timeserver corrected the system time. I now started to explore. Thats what I've found: In if-up.d directory ntpdate-debian is called. This one uses /etc/default/ntpdate as a config file. In my configfile NTPDATE_USE_NTP_CONF was set
to 'yes'. But ntp has never been installed on my system (as far as i know) and so config files for ntp did not exist (such as /etc/ntp.conf). So no servers from ntp, NTPSERVERS=ntp.ubuntu.com from /etc/defaut/ntpdate not used --> no syncing time.
Workaround: Installed ntp and removed it. -> /etc/ntp.conf now exists -> ntpdate-debian syncs system time.

BTW: I'm on lucid
greetings!

ProblemType: Bug
Architecture: i386
Date: Thu Mar 11 16:55:15 2010
DistroRelease: Ubuntu 10.04
Package: ntpdate 1:4.2.4p8+dfsg-1ubuntu1 [modified: usr/sbin/ntpdate-debian]
ProcEnviron:
LANGUAGE=en_GB:en
PATH=(custom, user)
LANG=en_GB.UTF-8
SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.32-16.25-generic
SourcePackage: ntp
Uname: Linux 2.6.32-16-generic i686

Tags:

Revision history for this message

Hans-Peter (hanspeterg) wrote on 2010-03-11:

Dependencies.txt Edit (682 bytes, text/plain; charset="utf-8")

Revision history for this message

Mathias Gug (mathiaz) wrote on 2010-03-16:

ntpdate-debian uses /etc/default/ntpdate for its configuration file. /etc/default/ntpdate should have a list of ntp servers in it:

# Set to "yes" to take the server list from /etc/ntp.conf, from package ntp,
# so you only have to keep it in one place.
NTPDATE_USE_NTP_CONF=yes

# List of NTP servers to use (Separate multiple servers with spaces.)
# Not used if NTPDATE_USE_NTP_CONF is yes.
NTPSERVERS="ntp.ubuntu.com"

I'm not sure what your problem is. ntpdate-debian is run only *once* when the network interface is brought up. If the system has been running from some time and the time drifted ntpdate-debian won't fix the time in a continuous manner: this is what ntp is for.

To summarize: ntpdate-debian corrects the time once, ntp corrects the time continuously.

Changed in ntp (Ubuntu):
importance:	Undecided → Low
status:	New → Incomplete

Revision history for this message

Hans-Peter (hanspeterg) wrote on 2010-03-16:

Hi!
No problem with continous synchronisation! Problem was: /etc/default/ntpdate says NTPDATE_USE_NTP_CONF=yes.
But /etc/ntp.conf does not exist, because ntp is not installed. -> nptdate-debian fails. At least I think so, because my system time was not correct.

Revision history for this message

Mathias Gug (mathiaz) wrote on 2010-03-16: Re: [Bug 537451] Re: ntpdate-debian not syncing time

On Tue, Mar 16, 2010 at 06:02:53PM -0000, Hans-Peter wrote:
>
> No problem with continous synchronisation! Problem was: /etc/default/ntpdate says NTPDATE_USE_NTP_CONF=yes.
> But /etc/ntp.conf does not exist, because ntp is not installed. -> nptdate-debian fails.

ntddate-debian doesn't use /etc/ntp.conf. It uses the time servers listed in /etc/default/ntpdate.

> At least I think so, because my system time was not correct.

ntpdate-debian is run *only* when network interfaces are brought up and will
correct the time *once*. If the system time drifts afterwards nothing will
correct it. If the system ran for a long time with no network interface change
the time could drift a lot.

--
Mathias Gug
Ubuntu Developer http://www.ubuntu.com

Revision history for this message

Hans-Peter (hanspeterg) wrote on 2010-03-16: Re: ntpdate-debian not syncing time

I just read the code of ntpdate-debian and did some testing. It is just that I have misunderstood the comment in /etc/default/ntpdate.
It says "# Set to "yes" to take the server list from /etc/ntp.conf ....". I understand now, that this is just an option. If the file is not there, even if NTPDATE_USE_NTP_CONF is set to yes, ntpdate-debian is working. So please close this bug report.
I will have to find out what is messing up my system time.
best regards,
Hans-Peter

Revision history for this message

Mathias Gug (mathiaz) wrote on 2010-03-17:

You're right. The comments in /etc/default/ntpdate are confusing.

summary:	- ntpdate-debian not syncing time + Confusing comments in /etc/default/ntpdate
Changed in ntp (Ubuntu):
importance:	Low → Wishlist
status:	Incomplete → Triaged

Thierry Carrez (ttx) on 2010-06-29

Changed in server-papercuts:
importance:	Undecided → Low
milestone:	none → maverick-alpha-3
status:	New → Triaged

Dave Walker (davewalker) on 2010-06-29

Changed in server-papercuts:
assignee:	nobody → Dave Walker (davewalker)

Thierry Carrez (ttx) on 2010-08-03

Changed in server-papercuts:
milestone:	maverick-alpha-3 → maverick-beta

Revision history for this message

Mathias Gug (mathiaz) wrote on 2010-08-25:

Marking won't fix as the comment is good enough IMO.

Changed in server-papercuts:
status:	Triaged → Won't Fix
Changed in ntp (Ubuntu):
status:	Triaged → Won't Fix

Revision history for this message

Kevin (kevin-matson) wrote on 2012-07-24:

I respect the package maintainers decision to let this one slide but the comment in /etc/default/ntpdate is confusing. You shouldn't have to read the code to figure out that if /etc/ntp.conf doesn't exist that a different NTP server will be used. Thanks for the clarification via Launchpad.