systemd-timedated.service, systemd-timedated — Time and date bus mechanism
systemd-timedated.service
/usr/lib/systemd/systemd-timedated
systemd-timedated.service is a system service
that may be used as a mechanism to change the system clock and
timezone, as well as to enable/disable network time synchronization.
systemd-timedated is automatically activated
on request and terminates itself when it is unused.
The tool timedatectl(1) is a command line client to this service.
systemd-timedated currently offers access to
the following four settings:
The system time
The system timezone
A boolean controlling whether the system RTC is in local or UTC timezone
Whether the time synchronization service is enabled/started or disabled/stopped, see next section.
See org.freedesktop.timedate1(5) and org.freedesktop.LogControl1(5) for information about the D-Bus API.
systemd-timesyncd will look for files with a ".list" extension
in ntp-units.d/ directories. Each file is parsed as a list of unit names, one per
line. Empty lines and lines with comments ("#") are ignored. Files are read from
/usr/lib/systemd/ntp-units.d/ and the corresponding directories under
/etc/, /run/, /usr/local/lib/. Files in
/etc/ override files with the same name in /run/,
/usr/local/lib/, and /usr/lib/. Files in
/run/ override files with the same name under /usr/. Packages
should install their configuration files in /usr/lib/ (distribution packages) or
/usr/local/lib/ (local installs).
Example 1. ntp-units.d/ entry for systemd-timesyncd
# /usr/lib/systemd/ntp-units.d/80-systemd-timesync.list systemd-timesyncd.service
If the environment variable $SYSTEMD_TIMEDATED_NTP_SERVICES is set,
systemd-timesyncd will parse the contents of that variable as a colon-separated list
of unit names. When set, this variable overrides the file-based list described above.
Example 2. An override that specifies that chronyd should be used if available
SYSTEMD_TIMEDATED_NTP_SERVICES=chronyd.service:systemd-timesyncd.service