244 lines
8 KiB
Text
244 lines
8 KiB
Text
This is the README for chrony.
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What is chrony?
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===============
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chrony is a versatile implementation of the Network Time Protocol (NTP).
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It can synchronize the system clock with NTP servers, reference clocks
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(e.g. GPS receiver), and manual input using wristwatch and keyboard.
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It can also operate as an NTPv4 (RFC 5905) server and peer to provide
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a time service to other computers in the network.
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It is designed to perform well in a wide range of conditions, including
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intermittent network connections, heavily congested networks, changing
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temperatures (ordinary computer clocks are sensitive to temperature),
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and systems that do not run continuosly, or run on a virtual machine.
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Typical accuracy between two machines on a LAN is in tens, or a few
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hundreds, of microseconds; over the Internet, accuracy is typically
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within a few milliseconds. With a good hardware reference clock
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sub-microsecond accuracy is possible.
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Two programs are included in chrony, chronyd is a daemon that can be
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started at boot time and chronyc is a command-line interface program
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which can be used to monitor chronyd's performance and to change various
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operating parameters whilst it is running.
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What will chrony run on?
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========================
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The software is known to work on Linux, FreeBSD, NetBSD, Mac OS X and
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Solaris. Closely related systems may work too. Any other system will
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likely require a porting exercise. You would need to start from one
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of the existing system-specific drivers and look into the quirks of
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certain system calls and the kernel on your target system.
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How do I set it up?
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===================
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The file INSTALL gives instructions. On supported systems the
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compilation process should be automatic.
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You will need an ANSI C compiler -- gcc is recommended.
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The manual (in texinfo and text formats) describes how to set the
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software up for the less straightforward cases.
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What documentation is there?
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============================
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A manual is supplied in Texinfo format (chrony.texi) and
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ready-formatted plain text (chrony.txt) in the distribution.
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There is also information available on the chrony web pages, accessible
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through the URL
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https://chrony.tuxfamily.org/
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Where are new versions announced?
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=================================
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There is a low volume mailing list where new versions and other
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important news relating to chrony is announced. You can join this list
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by sending mail with the subject "subscribe" to
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chrony-announce-request@chrony.tuxfamily.org
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These messages will be copied to chrony-users (see below).
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How can I get support for chrony?
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and where can I discuss new features, possible bugs etc?
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========================================================
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There are 3 mailing lists relating to chrony. chrony-announce was
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mentioned above. chrony-users is a users' discussion list, e.g. for
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general questions and answers about using chrony. chrony-dev is a more
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technical list, e.g. for discussing how new features should be
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implemented, exchange of information between developers etc. To
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subscribe to either of these lists, send a message with the subject
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"subscribe" to
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chrony-users-request@chrony.tuxfamily.org
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or
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chrony-dev-request@chrony.tuxfamily.org
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as applicable.
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When you are reporting a bug, please send us all the information you can.
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Unfortunately, chrony has proven to be one of those programs where it is very
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difficult to reproduce bugs in a different environment. So we may have to
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interact with you quite a lot to obtain enough extra logging and tracing to
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pin-point the problem in some cases. Please be patient and plan for this!
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License
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=======
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chrony is distributed under the GNU General Public License version 2.
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Author
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======
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Richard P. Curnow <rc@rc0.org.uk>
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Maintainers
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===========
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Miroslav Lichvar <mlichvar@redhat.com>
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Acknowledgements
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================
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In writing the chronyd program, extensive use has been made of RFC 1305
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and RFC 5905, written by David Mills. The source code of the NTP reference
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implementation has been used to check the details of the protocol.
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The following people have provided patches and other major contributions
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to the program :
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Benny Lyne Amorsen <benny@amorsen.dk>
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Patch to add minstratum option
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Andrew Bishop <amb@gedanken.demon.co.uk>
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Fixes for bugs in logging when in daemon mode
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Fixes for compiler warnings
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Robustness improvements for drift file
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Improve installation (directory checking etc)
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Entries in contrib directory
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Improvements to 'sources' and 'sourcestats' output from chronyc
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Improvements to documentation
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Investigation of required dosynctodr behaviour for various Solaris
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versions.
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Stephan I. Boettcher <stephan@nevis1.columbia.edu>
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Entries in contrib directory
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Erik Bryer <ebryer@spots.ab.ca>
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Entries in contrib directory
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Bryan Christianson <bryan@whatroute.net>
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Support for Mac OS X
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Support for privilege separation
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Juliusz Chroboczek <jch@pps.jussieu.fr>
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Fix install rule in Makefile if chronyd file is in use.
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Paul Elliott <pelliott@io.com>
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DNSchrony (in contrib directory), a tool for handling NTP servers
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with variable IP addresses.
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Mike Fleetwood <mike@rockover.demon.co.uk>
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Fixes for compiler warnings
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Alexander Gretencord <arutha@gmx.de>
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Changes to installation directory system to make it easier for
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package builders.
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Andrew Griffiths <agriffit@redhat.com>
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Patch to add support for seccomp filter
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Walter Haidinger <walter.haidinger@gmx.at>
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Providing me with login access to a Linux installation where v1.12
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wouldn't compile, so I could develop the fixes for v1.13. Also, for
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providing the disc space so I can keep an independent backup of the
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sources.
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Juergen Hannken-Illjes <hannken@eis.cs.tu-bs.de>
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Port to NetBSD
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John Hasler <john@dhh.gt.org>
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Project and website at tuxfamily.org
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Changes to support 64 bit machines (i.e. those where
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sizeof(unsigned long) > 4)
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Bug fix to initstepslew directive
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Fix to remove potential buffer overrun errors.
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Memory locking and real-time scheduler support
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Fix fault where chronyd enters an endless loop
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Tjalling Hattink <t.hattink@fugro.nl>
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Fix scheduler to allow stepping clock from timeout handler
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Patch to take leap second in PPS refclock from locked source
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Patch to make reading of RTC for initial trim more reliable
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Liam Hatton <me@liamhatton.com>
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Advice on configuring for Linux on PPC
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Jachym Holecek <jakym@volny.cz>
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Patch to make Linux real time clock work with devfs
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Håkan Johansson <f96hajo@chalmers.se>
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Patch to avoid large values in sources and sourcestats output
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Jim Knoble <jmknoble@pobox.com>
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Fixes for compiler warnings
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Antti Jrvinen <costello@iki.fi>
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Advice on configuring for BSD/386
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Miroslav Lichvar <mlichvar@redhat.com>
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Reference clock support
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IPv6 support
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Linux capabilities support
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Leap second support
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Improved source selection
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Improved sample history trimming
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Improved polling interval adjustment
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Improved stability with temporary asymmetric delays
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Temperature compensation
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Many other bug fixes and improvements
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Victor Moroz <vim@prv.adlum.ru>
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Patch to support Linux with HZ!=100
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Kalle Olavi Niemitalo <tosi@stekt.oulu.fi>
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acquisitionport support
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Frank Otto <sandwichmacher@web.de>
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Handling arbitrary HZ values
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Gautier PHILIPPON <gautier.philippon@ensimag.grenoble-inp.fr>
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Patch to add refresh command to chronyc
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Andreas Piesk <apiesk@virbus.de>
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Patch to make chronyc use the readline library if available
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Timo Teras <timo.teras@iki.fi>
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Patch to reply correctly on multihomed hosts
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Wolfgang Weisselberg <weissel@netcologne.de>
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Entries in contrib directory
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Ralf Wildenhues <Ralf.Wildenhues@gmx.de>
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Many robustness and security improvements
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Ulrich Windl <ulrich.windl@rz.uni-regensburg.de> for the
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Providing me with information about the Linux 2.2 kernel
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functionality compared to 2.0.
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Doug Woodward <dougw@whistler.com>
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Advice on configuring for Solaris 2.8 on x86
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Many other people have contributed bug reports and suggestions. I'm
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sorry I can't identify all of you individually.
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