[systemd-devel] Upstream service file for NTP daemon chrony

[Paul Menzel]

Dear systemd folks,


I got some private (I do not know why) replies regarding this service
files giving me some hints.


Am Freitag, den 22.06.2012, 11:57 +0200 schrieb Paul Menzel:

> Fedora ships systemd service files for chrony [1][2].
> 
> • chrony-wait.service:
> 
>    1 [Unit]
>    2 Description=Wait for chrony to synchronize system clock
>    3 After=chronyd.service
>    4 Requires=chronyd.service
>    5 Before=time-sync.target
>    6 Wants=time-sync.target
>    7 
>    8 [Service]
>    9 Type=oneshot
>   10 # Wait up to ~10 minutes for chronyd to synchronize and the remaining
>   11 # clock correction to be less than 0.1 seconds
>   12 ExecStart=/usr/bin/chronyc waitsync 60 0.1
>   13 RemainAfterExit=yes
>   14 
>   15 [Install]
>   16 WantedBy=multi-user.target
> 
> • chronyd.service:
> 
>    1 [Unit]
>    2 Description=NTP client/server
>    3 After=syslog.target ntpdate.service
>    4 Conflicts=ntpd.service
>    5 BindTo=systemd-timedated-ntp.target
>    6 
>    7 [Service]
>    8 Type=forking
>    9 EnvironmentFile=-/etc/sysconfig/chronyd
>   10 ExecStartPre=/usr/libexec/chrony-helper generate-commandkey
>   11 ExecStart=/usr/sbin/chronyd -u chrony $OPTIONS
>   12 ExecStartPost=/usr/libexec/chrony-helper add-dhclient-servers
>   13 
>   14 [Install]
>   15 WantedBy=multi-user.target
> 
> Do these look good enough to get upstream? `systemd-arch-units` refused
> a pull request [3].

It was pointed out that the service files above are very Fedora
specific. Mantas pointed out that Arch Linux now ships unit files
directly [4]

        [Unit]
        Description=Chrony Network Time Daemon
        
        [Service]
        Type=forking
        ExecStart=/usr/sbin/chronyd
        PIDFile=/var/run/chronyd.pid
        
        [Install]
        WantedBy=multi-user.target

and therefore the pull request above was rejected. Furthermore David had
some great ideas whose result is quite similar to the service file in
Arch Linux.

        [Unit]
        Description=Chrony Network Time Daemon
        After=nss-lockup.target syslog.target

        [Service]
        ExecStart=/usr/sbin/chronyd -n

        [Install]
        WantedBy=multi-user.target

David suggested that a separate system user could be used for this
daemon too and systemd should do this.

But it looks like that Arch Linux or Debian assume `chronyd` is run as
`root` and do not set up devices or certain files for time setting to be
used by a different user than root.

Additionally `After=nss-lockup.target` should be set, so that the NTP
daemon actually finds a NTP server.

And lastly, in the directory `units/` of the systemd source tree
contains `time-sync.target` and the Fedora services use that too. But
reading the manual of systemd.special, my take on this is this is just a
compatibility file and should not be used in a systemd service file.

So does the last service file look reasonable and should be used for
upstream inclusion?


Thanks,

Paul


> [1] http://pkgs.fedoraproject.org/gitweb/?p=chrony.git;a=blob;f=chrony-wait.service;h=3958160098eae926aaf7136d7b5b8bab42a6aa35;hb=HEAD
> [2] http://pkgs.fedoraproject.org/gitweb/?p=chrony.git;a=blob;f=chronyd.service;h=167332e37511f19019aabc32f82a47ef80656cd5;hb=HEAD
> [3] https://github.com/falconindy/systemd-arch-units/issues/98
[4] https://projects.archlinux.org/svntogit/community.git/tree/trunk/service?h=packages/chrony
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