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)