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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-05 18:43:21 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-05 18:43:21 +0000 |
commit | 104f986b0650b8f93540785d2bcf486905e49b62 (patch) | |
tree | 2b2ae5113d9b57425d4bb3f726e325316b87e00a /doc/chronyd.man.in | |
parent | Initial commit. (diff) | |
download | chrony-104f986b0650b8f93540785d2bcf486905e49b62.tar.xz chrony-104f986b0650b8f93540785d2bcf486905e49b62.zip |
Adding upstream version 3.4.upstream/3.4upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'doc/chronyd.man.in')
-rw-r--r-- | doc/chronyd.man.in | 211 |
1 files changed, 211 insertions, 0 deletions
diff --git a/doc/chronyd.man.in b/doc/chronyd.man.in new file mode 100644 index 0000000..6342f1b --- /dev/null +++ b/doc/chronyd.man.in @@ -0,0 +1,211 @@ +'\" t +.\" Title: chronyd +.\" Author: [see the "AUTHORS" section] +.\" Generator: Asciidoctor 1.5.6.1 +.\" Date: 2018-09-19 +.\" Manual: System Administration +.\" Source: chrony @CHRONY_VERSION@ +.\" Language: English +.\" +.TH "CHRONYD" "8" "2018-09-19" "chrony @CHRONY_VERSION@" "System Administration" +.ie \n(.g .ds Aq \(aq +.el .ds Aq ' +.ss \n[.ss] 0 +.nh +.ad l +.de URL +\\$2 \(laURL: \\$1 \(ra\\$3 +.. +.if \n[.g] .mso www.tmac +.LINKSTYLE blue R < > +.SH "NAME" +chronyd \- chrony daemon +.SH "SYNOPSIS" +.sp +\fBchronyd\fP [\fIOPTION\fP]... [\fIDIRECTIVE\fP]... +.SH "DESCRIPTION" +.sp +\fBchronyd\fP is a daemon for synchronisation of the system clock. It can +synchronise the clock with NTP servers, reference clocks (e.g. a GPS receiver), +and manual input using wristwatch and keyboard via \fBchronyc\fP. It can also +operate as an NTPv4 (RFC 5905) server and peer to provide a time service to +other computers in the network. +.sp +If no configuration directives are specified on the command line, \fBchronyd\fP +will read them from a configuration file. The compiled\-in default location of +the file is \fI@SYSCONFDIR@/chrony.conf\fP. +.sp +Information messages and warnings will be logged to syslog. +.SH "OPTIONS" +.sp +\fB\-4\fP +.RS 4 +With this option hostnames will be resolved only to IPv4 addresses and only +IPv4 sockets will be created. +.RE +.sp +\fB\-6\fP +.RS 4 +With this option hostnames will be resolved only to IPv6 addresses and only +IPv6 sockets will be created. +.RE +.sp +\fB\-f\fP \fIfile\fP +.RS 4 +This option can be used to specify an alternate location for the configuration +file (default \fI@SYSCONFDIR@/chrony.conf\fP). +.RE +.sp +\fB\-n\fP +.RS 4 +When run in this mode, the program will not detach itself from the terminal. +.RE +.sp +\fB\-d\fP +.RS 4 +When run in this mode, the program will not detach itself from the terminal, +and all messages will be written to the terminal instead of syslog. When +\fBchronyd\fP was compiled with debugging support, this option can be used twice to +print also debugging messages. +.RE +.sp +\fB\-l\fP \fIfile\fP +.RS 4 +This option specifies a file which should be used for logging instead of syslog +or terminal. +.RE +.sp +\fB\-q\fP +.RS 4 +When run in this mode, \fBchronyd\fP will set the system clock once and exit. It +will not detach from the terminal. +.RE +.sp +\fB\-Q\fP +.RS 4 +This option is similar to the \fB\-q\fP option, except it only prints the offset +without making any corrections of the clock and it allows \fBchronyd\fP to be +started without root privileges. +.RE +.sp +\fB\-r\fP +.RS 4 +This option will try to reload and then delete files containing sample +histories for each of the servers and reference clocks being used. The +files are expected to be in the directory specified by the +\fBdumpdir\fP +directive in the configuration file. This option is useful if you want to stop +and restart \fBchronyd\fP briefly for any reason, e.g. to install a new version. +However, it should be used only on systems where the kernel can maintain clock +compensation whilst not under \fBchronyd\fP\(cqs control (i.e. Linux, FreeBSD, NetBSD, +Solaris, and macOS 10.13 or later). +.RE +.sp +\fB\-R\fP +.RS 4 +When this option is used, the \fBinitstepslew\fP +directive and the \fBmakestep\fP directive used with +a positive limit will be ignored. This option is useful when restarting +\fBchronyd\fP and can be used in conjunction with the \fB\-r\fP option. +.RE +.sp +\fB\-s\fP +.RS 4 +This option will set the system clock from the computer\(cqs real\-time clock (RTC) +or to the last modification time of the file specified by the +\fBdriftfile\fP directive. Real\-time clocks are +supported only on Linux. +.sp +If used in conjunction with the \fB\-r\fP flag, \fBchronyd\fP will attempt to preserve +the old samples after setting the system clock from the RTC. This can be used +to allow \fBchronyd\fP to perform long term averaging of the gain or loss rate +across system reboots, and is useful for systems with intermittent access to +network that are shut down when not in use. For this to work well, it relies +on \fBchronyd\fP having been able to determine accurate statistics for the +difference between the RTC and system clock last time the computer was on. +.sp +If the last modification time of the drift file is later than both the current +time and the RTC time, the system time will be set to it to restore the time +when \fBchronyd\fP was previously stopped. This is useful on computers that have no +RTC or the RTC is broken (e.g. it has no battery). +.RE +.sp +\fB\-t\fP \fItimeout\fP +.RS 4 +This option sets a timeout (in seconds) after which \fBchronyd\fP will exit. If the +clock is not synchronised, it will exit with a non\-zero status. This is useful +with the \fB\-q\fP or \fB\-Q\fP option to shorten the maximum time waiting for +measurements, or with the \fB\-r\fP option to limit the time when \fBchronyd\fP is +running, but still allow it to adjust the frequency of the system clock. +.RE +.sp +\fB\-u\fP \fIuser\fP +.RS 4 +This option sets the name of the system user to which \fBchronyd\fP will switch +after start in order to drop root privileges. It overrides the +\fBuser\fP directive (default \fI@DEFAULT_USER@\fP). +.sp +On Linux, \fBchronyd\fP needs to be compiled with support for the \fBlibcap\fP library. +On macOS, FreeBSD, NetBSD and Solaris \fBchronyd\fP forks into two processes. +The child process retains root privileges, but can only perform a very limited +range of privileged system calls on behalf of the parent. +.RE +.sp +\fB\-F\fP \fIlevel\fP +.RS 4 +This option configures a system call filter when \fBchronyd\fP is compiled with +support for the Linux secure computing (seccomp) facility. In level 1 the +process is killed when a forbidden system call is made, in level \-1 the SIGSYS +signal is thrown instead and in level 0 the filter is disabled (default 0). +.sp +It\(cqs recommended to enable the filter only when it\(cqs known to work on the +version of the system where \fBchrony\fP is installed as the filter needs to allow +also system calls made from libraries that \fBchronyd\fP is using (e.g. libc) and +different versions or implementations of the libraries may make different +system calls. If the filter is missing some system call, \fBchronyd\fP could be +killed even in normal operation. +.RE +.sp +\fB\-P\fP \fIpriority\fP +.RS 4 +On Linux, this option will select the SCHED_FIFO real\-time scheduler at the +specified priority (which must be between 0 and 100). On macOS, this option +must have either a value of 0 (the default) to disable the thread time +constraint policy or 1 for the policy to be enabled. Other systems do not +support this option. +.RE +.sp +\fB\-m\fP +.RS 4 +This option will lock \fBchronyd\fP into RAM so that it will never be paged out. +This mode is only supported on Linux. +.RE +.sp +\fB\-x\fP +.RS 4 +This option disables the control of the system clock. \fBchronyd\fP will not try to +make any adjustments of the clock. It will assume the clock is free running and +still track its offset and frequency relative to the estimated true time. This +option allows \fBchronyd\fP to run without the capability to adjust or set the +system clock (e.g. in some containers) in order to operate as an NTP server. It +is not recommended to run \fBchronyd\fP (with or without \fB\-x\fP) when another process +is controlling the system clock. +.RE +.sp +\fB\-v\fP +.RS 4 +With this option \fBchronyd\fP will print version number to the terminal and exit. +.RE +.SH "FILES" +.sp +\fI@SYSCONFDIR@/chrony.conf\fP +.SH "SEE ALSO" +.sp +\fBchronyc(1)\fP, \fBchrony.conf(5)\fP +.SH "BUGS" +.sp +For instructions on how to report bugs, please visit +.URL "https://chrony.tuxfamily.org/" "" "." +.SH "AUTHORS" +.sp +chrony was written by Richard Curnow, Miroslav Lichvar, and others.
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