systemd-timesyncd

SYSTEMD-TIMESYNCD.SERVICE(8systemd-timesyncd.serviSYSTEMD-TIMESYNCD.SERVICE(8)

NAME
       systemd-timesyncd.service, systemd-timesyncd - Network Time
       Synchronization

SYNOPSIS
       systemd-timesyncd.service

       /lib/systemd/systemd-timesyncd

DESCRIPTION
       systemd-timesyncd is a system service that may be used to synchronize
       the local system clock with a remote Network Time Protocol (NTP)
       server. It also saves the local time to disk every time the clock has
       been synchronized and uses this to possibly advance the system realtime
       clock on subsequent reboots to ensure it (roughly) monotonically
       advances even if the system lacks a battery-buffered RTC chip.

       The systemd-timesyncd service implements SNTP only. This minimalistic
       service will step the system clock for large offsets or slowly adjust
       it for smaller deltas. Complex use cases that require full NTP support
       (and where SNTP is not sufficient) are not covered by
       systemd-timesyncd.

       The NTP servers contacted are determined from the global settings in
       timesyncd.conf(5), the per-link static settings in .network files, and
       the per-link dynamic settings received over DHCP. See
       systemd.network(5) for further details.

       timedatectl(1)'s set-ntp command may be used to enable and start, or
       disable and stop this service.

       timedatectl(1)'s timesync-status or show-timesync command can be used
       to show the current status of this service.

       systemd-timesyncd initialization delays the start of units that are
       ordered after time-set.target (see systemd.special(7) for details)
       until the local time has been updated from
       /var/lib/systemd/timesync/clock (see below) in order to make it roughly
       monotonic. It does not delay other units until synchronization with an
       accurate reference time sources has been reached. Use systemd-time-
       wait-sync.service(8) to achieve that, which will delay start of units
       that are ordered after time-sync.target until synchronization to an
       accurate reference clock is reached.

FILES
       /var/lib/systemd/timesync/clock
           The modification time ("mtime") of this file indicates the
           timestamp of the last successful synchronization (or at least the
           systemd build date, in case synchronization was not possible). It
           is used to ensure that the system clock remains roughly monotonic
           across reboots, in case no local RTC is available.

       /run/systemd/timesync/synchronized
           A file that is touched on each successful synchronization, to
           assist systemd-time-wait-sync and other applications to detecting
           synchronization with accurate reference clocks.

SEE ALSO
       systemd(1), timesyncd.conf(5), systemd.network(5), systemd-
       networkd.service(8), systemd-time-wait-sync.service(8),
       systemd.special(7), timedatectl(1), localtime(5), hwclock(8)

systemd 249                                       SYSTEMD-TIMESYNCD.SERVICE(8)