timesyncd.conf(5) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | CONFIGURATION DIRECTORIES AND PRECEDENCE | OPTIONS | SEE ALSO | COLOPHON

TIMESYNCD.CONF(5)            timesyncd.conf            TIMESYNCD.CONF(5)

NAME         top

       timesyncd.conf, timesyncd.conf.d - Network Time Synchronization
       configuration files

SYNOPSIS         top

       /etc/systemd/timesyncd.conf

       /etc/systemd/timesyncd.conf.d/*.conf

       /run/systemd/timesyncd.conf.d/*.conf

       /usr/lib/systemd/timesyncd.conf.d/*.conf

DESCRIPTION         top

       These configuration files control NTP network time
       synchronization. See systemd.syntax(7) for a general description
       of the syntax.

CONFIGURATION DIRECTORIES AND PRECEDENCE         top

       The default configuration is set during compilation, so
       configuration is only needed when it is necessary to deviate from
       those defaults. Initially, the main configuration file in
       /etc/systemd/ contains commented out entries showing the defaults
       as a guide to the administrator. Local overrides can be created
       by editing this file or by creating drop-ins, as described below.
       Using drop-ins for local configuration is recommended over
       modifications to the main configuration file.

       In addition to the "main" configuration file, drop-in
       configuration snippets are read from /usr/lib/systemd/*.conf.d/,
       /usr/local/lib/systemd/*.conf.d/, and /etc/systemd/*.conf.d/.
       Those drop-ins have higher precedence and override the main
       configuration file. Files in the *.conf.d/ configuration
       subdirectories are sorted by their filename in lexicographic
       order, regardless of in which of the subdirectories they reside.
       When multiple files specify the same option, for options which
       accept just a single value, the entry in the file sorted last
       takes precedence, and for options which accept a list of values,
       entries are collected as they occur in the sorted files.

       When packages need to customize the configuration, they can
       install drop-ins under /usr/. Files in /etc/ are reserved for the
       local administrator, who may use this logic to override the
       configuration files installed by vendor packages. Drop-ins have
       to be used to override package drop-ins, since the main
       configuration file has lower precedence. It is recommended to
       prefix all filenames in those subdirectories with a two-digit
       number and a dash, to simplify the ordering of the files.

       To disable a configuration file supplied by the vendor, the
       recommended way is to place a symlink to /dev/null in the
       configuration directory in /etc/, with the same filename as the
       vendor configuration file.

OPTIONS         top

       The following settings are configured in the [Time] section:

       NTP=
           A space-separated list of NTP server host names or IP
           addresses. During runtime this list is combined with any
           per-interface NTP servers acquired from
           systemd-networkd.service(8).  systemd-timesyncd will contact
           all configured system or per-interface servers in turn, until
           one responds. When the empty string is assigned, the list of
           NTP servers is reset, and all prior assignments will have no
           effect. This setting defaults to an empty list.

       FallbackNTP=
           A space-separated list of NTP server host names or IP
           addresses to be used as the fallback NTP servers. Any
           per-interface NTP servers obtained from
           systemd-networkd.service(8) take precedence over this
           setting, as do any servers set via NTP= above. This setting
           is hence only relevant if no other NTP server information is
           known. When the empty string is assigned, the list of NTP
           servers is reset, and all prior assignments will have no
           effect. If this option is not given, a compiled-in list of
           NTP servers is used.

       RootDistanceMaxSec=
           Maximum acceptable root distance, i.e. the maximum estimated
           time required for a packet to travel to the server we are
           connected to from the server with the reference clock. If the
           current server does not satisfy this limit, systemd-timesyncd
           will switch to a different server.

           Takes a time span value. The default unit is seconds, but
           other units may be specified, see systemd.time(5). Defaults
           to 5 seconds.

       PollIntervalMinSec=, PollIntervalMaxSec=
           The minimum and maximum poll intervals for NTP messages.
           Polling starts at the minimum poll interval, and is adjusted
           within the specified limits in response to received packets.

           Each setting takes a time span value. The default unit is
           seconds, but other units may be specified, see
           systemd.time(5).  PollIntervalMinSec= defaults to 32 seconds
           and must not be smaller than 16 seconds.  PollIntervalMaxSec=
           defaults to 34 min 8 s (2048 seconds) and must be larger than
           PollIntervalMinSec=.

       ConnectionRetrySec=
           Specifies the minimum delay before subsequent attempts to
           contact a new NTP server are made.

           Takes a time span value. The default unit is seconds, but
           other units may be specified, see systemd.time(5). Defaults
           to 30 seconds and must not be smaller than 1 second.

SEE ALSO         top

       systemd(1), systemd-timesyncd.service(8),
       systemd-networkd.service(8)

COLOPHON         top

       This page is part of the systemd (systemd system and service
       manager) project.  Information about the project can be found at
       ⟨http://www.freedesktop.org/wiki/Software/systemd⟩.  If you have
       a bug report for this manual page, see
       ⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩.
       This page was obtained from the project's upstream Git repository
       ⟨https://github.com/systemd/systemd.git⟩ on 2021-06-20.  (At that
       time, the date of the most recent commit that was found in the
       repository was 2021-06-19.)  If you discover any rendering
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       is a better or more up-to-date source for the page, or you have
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       (which is not part of the original manual page), send a mail to
       man-pages@man7.org

systemd 249                                            TIMESYNCD.CONF(5)

Pages that refer to this page: systemd.directives(7)systemd.index(7)systemd.syntax(7)systemd-timesyncd.service(8)