[pkg-ntp-maintainers] Bug#289267: Debian #289267: ntpdate should use ifupdown instead of rcS to start

[Scott James Remnant]

Matt's asked me to jump in here to explain the Ubuntu changes, and our
long-term plan for such thing; as there seems to be a little confusion
and/or argument on this topic.


On Fri, 5 May 2006 15:17:53 +0200, Ingo Oeser wrote:

> The proposed solution of using /etc/networking/if-up.d/ works
> without any problem for most of your users. Actually unbuntu
> "Dapper Drake" is just doing it this way and I never had any problems.
> We fixed it for our customers the same way.
> 
Our reason for moving this to an if-up.d script is because we're
increasingly relying on udev to drive the hardware parts of our boot
sequence; this meant that there was no point in the SysV boot sequence
where "networking was up", so no point to run the ntpdate script.

Moving to an if-up.d script meant that the clock would be adjusted
during boot when the each ethernet card came up; the first not being
sufficient as that one might not actually get an IP.

This isn't ideal either, as now ntpdate gets run every time you fiddle
with an interface.  Our preferred solution is to use upstart to manage
the ntpdate task, and don't run it once it has succeeded at least once.


On Tue, 12 Dec 2006 08:41:12 +0100, Tore Anderson wrote:

> I know.  Maybe I should have been clearer though, what I'm objecting
> to is primarily the suggestion to mimic the way Ubuntu does it, as
> they invoke ntpdate with the "-b" parameter in the if-up.d script,
> ensuring that the clock will _always_ leap.
> 
We use "-b" because it was what was suggested in the manual page:

  -b  Force  the  time  to  be stepped using the settimeofday() system
      call, rather than slewed (default) using  the  adjtime()  system
      call. This option should be used when called from a startup file
      at boot time.

The if-up.d ntpdate script is intended to "set the clock at boot time",
once the first interface with a reachable ntp server has come up.

> If no NTP server is available at bootup, well, then you'll just have
> to wait for a network connection and possibly step the time then.
> 
That's what we're trying to do with the ntpdate script.


On Wed, 13 Dec 2006 12:01:36 +0100, Tore Anderson wrote:

> Ranked in order of preference (as defaults, at least):
>
>  1) No gratuitous clock adjustments whatsoever (no if-up.d script)
>  2) No gratuitous clock stepping whatsoever (use of -B)
>  3) No gratituous clock stepping unless large offset (default ntpdate)
>  4) Gratituous clock stepping (use of -b)
>
>  Ubuntu went with #4 for their Dapper release.
> 
Given the above, how would you recommend we sync the clock during boot
if no clock adjustments would be preferred?

Or are you referring specifically to additional clock adjustments after
the first one has been made?

Scott
-- 
Scott James Remnant
scott at ubuntu.com
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