#784148 Missing support for systems without battery-backed RTC

Package:
clock-setup
Source:
clock-setup
Submitter:
Ben Hutchings
Date:
2015-05-16 07:21:04 UTC
Severity:
important
#784148#5
Date:
2015-05-03 14:30:56 UTC
From:
To:
It is very important that Debian systems have an accurate system clock.
However not all supported systems include a battery-backed RTC (or any
working RTC).

Whenever there is not an RTC (and perhaps if there is an RTC but we
somehow recognise that it's not battery-backed), we should install and
enable a NTP daemon by default.  (Possibly we should do this by
default on everything.)

The NTP daemon should be a lightweight implementation intended for
clients, such as systemd-timesyncd, not the ntp package.  (In fact
systemd-timesyncd is installed already, it just isn't enabled.)

Ben.
#784148#10
Date:
2015-05-03 14:36:23 UTC
From:
To:
Somewhat relatedly, if there is no RTC then the systemd unit
hwclock-save.service should be disabled.

Ben.
#784148#15
Date:
2015-05-03 15:40:33 UTC
From:
To:
Debian installations on hardware with no (battery-backuped) RTC
is likely an installation that hasn't network connection.

So please do not push (too hard)
for "you MUST allway known what time it is"

Make it possible to do installs on hardware without RTC
and no access to a NTP server.


Installing fake-hwclock  https://packages.debian.org/stretch/fake-hwclock
on the absence of the a RTC


Avoiding filesystem checks when no RTC present would also be good.
Simular as https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=767040


Groeten
Geert Stappers
#784148#20
Date:
2015-05-03 16:23:30 UTC
From:
To:
Control: reassign -1 clock-setup
Control: retitle -1 Missing support for systems without battery-backed RTC

What makes you think that?

Of course this should still be supported.

Good point.

I'm retitling this because we now have three small related changes
wanted in the installer:

1. Install/enable NTP client
2. Disable hwclock-save.service
3. Disable e2fsck time check

I think these could all be done in clock-setup, so I'm reassigning to
that.

Ben.
#784148#29
Date:
2015-05-03 16:55:51 UTC
From:
To:
embedded systems, cheap embedded systems that have no real time clock,
those are the ones that I expect to be without network connection.
Example given: stand-alone mediaplayers.


My actual point:

  Do not assume when RTC is absence, then NTP server will be present.


Groeten
Geert Stappers
#784148#34
Date:
2015-05-03 17:17:52 UTC
From:
To:
The Debian installer is not meant for embedded systems, and Debian adds
a lot of bloat (=> cost).  Are you talking about replacing the original
OS on an embedded system to make it more flexible?

The installation/enablement of an NTP daemon should perhaps be dependent
on whether the network was configured during installation.  (Though that
is problematic if the network was not available due to missing firmware
or driver, and the system will have a network connection later.)

Ben.
#784148#39
Date:
2015-05-09 01:32:23 UTC
From:
To:
On Sun, 03 May 2015 17:23:30 +0100 Ben Hutchings <ben@decadent.org.uk> wrote:
http://anonscm.debian.org/cgit/pkg-systemd/systemd.git/commit/?h=experimental&id=929bece53261ddd2797d4f3518a05a88704c5b01
http://anonscm.debian.org/cgit/pkg-systemd/systemd.git/commit/?h=experimental&id=5ea1b2bd1c57f9d3095252229c4ba1e50a7248d6

We enable timesyncd by default now and have dropped the
hwclock-save.service in systemd for the systemd version targetted at
stretch.

Is there anything left which needs to be done?


Michael
#784148#44
Date:
2015-05-09 01:38:00 UTC
From:
To:
Am 09.05.2015 um 03:32 schrieb Michael Biebl:

See below for the changes in systemd

What exactly do you mean here?
stretch or do you want to see them in a jessie point release?
#784148#49
Date:
2015-05-09 01:52:14 UTC
From:
To:
e2fsck checks whether the current system time is earlier than the last
mount time of the filesystem.  If so, it may (depending on
configuration) perform a full check.

I don't know whether they are important enough to go into a point
release.

Ben.
#784148#54
Date:
2015-05-09 01:59:35 UTC
From:
To:
So what happens if another ntp daemon is packaged, or they move
executables into /usr/bin?

Point 3 still needs to be fixed; at least on systems not using
systemd-networkd the system clock will still be wrong when fsck runs.

Ben.
#784148#59
Date:
2015-05-09 10:29:49 UTC
From:
To:
Am 09.05.2015 um 03:59 schrieb Ben Hutchings:

Good question. I assume you refer to the
ConditionFileIsExecutable=!/usr/sbin/ntpd
etc.

This is a stop-gap, until all NTP services ship a native .service file.
Once they do so they are supposed to declare a
Conflicts=systemd-timesynd.service

Which means, if they are installed (and active), they will take
precedence over systemd-timesynd.service
#784148#64
Date:
2015-05-16 07:16:46 UTC
From:
To:
Isn't it possible to configure systemd so that it only starts certain
daemons if there's network? Having an NTP daemon installed on such
networks, and configured so that it does that, would alleviate that
concern.

(That would not fix the issue for non-systemd installs, but that
shouldn't be too much of a problem)