[systemd-devel] systemd-timesyncd with read-only root filesystem

[Martin Pitt]

Hello André,

André Hartmann [2016-12-08  9:28 +0100]:
> My main problem is that I cannot disable NTP by setting
> the link to /dev/null as the root partition is read-only.

Well, of course you can't change the image configuration after
building it -- you need to disable the service in the image build
process. If you don't have any writable files you can naturally not
change the unit configuration. Maybe I'm missing something here, but
this in no way timedated or even systemd specific?

> And till now I don't understand how timedatectl decides
> "NTP enabled: yes/no". I need a possibility to disable NTP
> in case the user will set the date by hand (also enabling
> it again if the user decides otherwise).

This actually sounds like you do want to keep at least parts of /etc/
writable, as otherwise there is no place to store things like
"disabled services" or "changed time zone".

> Which confuses me is the inconsistency between
> "systemctl status systemd.timesyncd" and "timedatectl status":
> 
> # systemctl status systemd.timesyncd
> *  systemd.timesyncd.service
>    Loaded: not-found (Reason: No such file or directory)
>    Active: inactive (dead)
> 
> # timedatectl status
>       Local time: Wed 2016-12-07 16:18:06 UTC
>   Universal time: Wed 2016-12-07 16:18:06 UTC
>         RTC time: n/a
>        Time zone: Universal (UTC, +0000)
>      NTP enabled: yes
> NTP synchronized: no
>  RTC in local TZ: no
>       DST active: n/a

I don't see an inconsistency? If timedated is not running then
timedatectl can't actualy talk to it and just shows values which it
can make up by itself.

Thanks,

Martin
-- 
Martin Pitt                        | http://www.piware.de
Ubuntu Developer (www.ubuntu.com)  | Debian Developer  (www.debian.org)