| '\" t |
| .\" Title: chronyc |
| .\" Author: [see the "AUTHORS" section] |
| .\" Generator: Asciidoctor 1.5.6.1 |
| .\" Date: 2018-04-04 |
| .\" Manual: User manual |
| .\" Source: chrony @CHRONY_VERSION@ |
| .\" Language: English |
| .\" |
| .TH "CHRONYC" "1" "2018-04-04" "chrony @CHRONY_VERSION@" "User manual" |
| .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" |
| chronyc \- command\-line interface for chrony daemon |
| .SH "SYNOPSIS" |
| .sp |
| \fBchronyc\fP [\fIOPTION\fP]... [\fICOMMAND\fP]... |
| .SH "DESCRIPTION" |
| .sp |
| \fBchronyc\fP is a command\-line interface program which can be used to monitor |
| \fBchronyd\fP\(cqs performance and to change various operating parameters whilst it is |
| running. |
| .sp |
| If no commands are specified on the command line, \fBchronyc\fP will expect input |
| from the user. The prompt \fIchronyc>\fP will be displayed when it is being run |
| from a terminal. If \fBchronyc\fP\(cqs input or output are redirected from or to a file, |
| the prompt is not shown. |
| .sp |
| There are two ways \fBchronyc\fP can access \fBchronyd\fP. One is the Internet |
| Protocol (IPv4 or IPv6) and the other is a Unix domain socket, which is |
| accessible locally by the root or \fIchrony\fP user. By default, \fBchronyc\fP first |
| tries to connect to the Unix domain socket. The compiled\-in default path is |
| \fI@CHRONYRUNDIR@/chronyd.sock\fP. If that fails (e.g. because \fBchronyc\fP is |
| running under a non\-root user), it will try to connect to 127.0.0.1 and then |
| ::1. |
| .sp |
| Only the following monitoring commands, which do not affect the behaviour of |
| \fBchronyd\fP, are allowed from the network: \fBactivity\fP, \fBmanual list\fP, |
| \fBrtcdata\fP, \fBsmoothing\fP, \fBsources\fP, \fBsourcestats\fP, \fBtracking\fP, \fBwaitsync\fP. The |
| set of hosts from which \fBchronyd\fP will accept these commands can be configured |
| with the \fBcmdallow\fP directive in the \fBchronyd\fP\(cqs |
| configuration file or the \fBcmdallow\fP command in \fBchronyc\fP. By |
| default, the commands are accepted only from localhost (127.0.0.1 or ::1). |
| .sp |
| All other commands are allowed only through the Unix domain socket. When sent |
| over the network, \fBchronyd\fP will respond with a \(oqNot authorised\(cq error, even |
| if it is from localhost. In chrony versions before 2.2 they were allowed |
| from the network if they were authenticated with a password, but that is no |
| longer supported. |
| .sp |
| Having full access to \fBchronyd\fP via \fBchronyc\fP is more or less equivalent to |
| being able to modify the \fBchronyd\fP\(cqs configuration file and restart it. |
| .SH "OPTIONS" |
| .sp |
| \fB\-4\fP |
| .RS 4 |
| With this option hostnames will be resolved only to IPv4 addresses. |
| .RE |
| .sp |
| \fB\-6\fP |
| .RS 4 |
| With this option hostnames will be resolved only to IPv6 addresses. |
| .RE |
| .sp |
| \fB\-n\fP |
| .RS 4 |
| This option disables resolving of IP addresses to hostnames, e.g. to avoid slow |
| DNS lookups. Long addresses will not be truncated to fit into the column. |
| .RE |
| .sp |
| \fB\-c\fP |
| .RS 4 |
| This option enables printing of reports in a comma\-separated values (CSV) |
| format. IP addresses will not be resolved to hostnames, time will be printed as |
| number of seconds since the epoch and values in seconds will not be converted |
| to other units. |
| .RE |
| .sp |
| \fB\-d\fP |
| .RS 4 |
| This option enables printing of debugging messages if \fBchronyc\fP was compiled |
| with debugging support. |
| .RE |
| .sp |
| \fB\-m\fP |
| .RS 4 |
| Normally, all arguments on the command line are interpreted as one command. |
| With this option multiple commands can be specified. Each argument will be |
| interpreted as a whole command. |
| .RE |
| .sp |
| \fB\-h\fP \fIhost\fP |
| .RS 4 |
| This option allows the user to specify which host (or comma\-separated list of |
| addresses) running the \fBchronyd\fP program is to be contacted. This allows for |
| remote monitoring, without having to connect over SSH to the other host first. |
| .sp |
| The default is to contact \fBchronyd\fP running on the same host where |
| \fBchronyc\fP is being run. |
| .RE |
| .sp |
| \fB\-p\fP \fIport\fP |
| .RS 4 |
| This option allows the user to specify the UDP port number which the target |
| \fBchronyd\fP is using for its monitoring connections. This defaults to 323; there |
| would rarely be a need to change this. |
| .RE |
| .sp |
| \fB\-f\fP \fIfile\fP |
| .RS 4 |
| This option is ignored and is provided only for compatibility. |
| .RE |
| .sp |
| \fB\-a\fP |
| .RS 4 |
| This option is ignored and is provided only for compatibility. |
| .RE |
| .sp |
| \fB\-v\fP |
| .RS 4 |
| With this option \fBchronyc\fP displays its version number on the terminal and |
| exits. |
| .RE |
| .SH "COMMANDS" |
| .sp |
| This section describes each of the commands available within the \fBchronyc\fP |
| program. |
| .SS "System clock" |
| .sp |
| \fBtracking\fP |
| .RS 4 |
| The \fBtracking\fP command displays parameters about the system\(cqs clock |
| performance. An example of the output is shown below. |
| .sp |
| .if n \{\ |
| .RS 4 |
| .\} |
| .nf |
| Reference ID : CB00710F (foo.example.net) |
| Stratum : 3 |
| Ref time (UTC) : Fri Jan 27 09:49:17 2017 |
| System time : 0.000006523 seconds slow of NTP time |
| Last offset : \-0.000006747 seconds |
| RMS offset : 0.000035822 seconds |
| Frequency : 3.225 ppm slow |
| Residual freq : \-0.000 ppm |
| Skew : 0.129 ppm |
| Root delay : 0.013639022 seconds |
| Root dispersion : 0.001100737 seconds |
| Update interval : 64.2 seconds |
| Leap status : Normal |
| .fi |
| .if n \{\ |
| .RE |
| .\} |
| .sp |
| The fields are explained as follows: |
| .sp |
| \fBReference ID\fP |
| .RS 4 |
| This is the reference ID and name (or IP address) of the server to which the |
| computer is currently synchronised. For IPv4 addresses, the reference ID is |
| equal to the address and for IPv6 addresses it is the first 32 bits of the MD5 |
| sum of the address. |
| .sp |
| If the reference ID is \fI7F7F0101\fP and there is no name or IP address, it means |
| the computer is not synchronised to any external source and that you have the |
| \fIlocal\fP mode operating (via the \fBlocal\fP command in \fBchronyc\fP, or the |
| \fBlocal\fP directive in the configuration file). |
| .sp |
| The reference ID is printed as a hexadecimal number. Note that in older |
| versions it used to be printed in quad\-dotted notation and could be confused |
| with an IPv4 address. |
| .RE |
| .sp |
| \fBStratum\fP |
| .RS 4 |
| The stratum indicates how many hops away from a computer with an attached |
| reference clock we are. Such a computer is a stratum\-1 computer, so the |
| computer in the example is two hops away (i.e. \fIfoo.example.net\fP is a |
| stratum\-2 and is synchronised from a stratum\-1). |
| .RE |
| .sp |
| \fBRef time\fP |
| .RS 4 |
| This is the time (UTC) at which the last measurement from the reference |
| source was processed. |
| .RE |
| .sp |
| \fBSystem time\fP |
| .RS 4 |
| In normal operation, \fBchronyd\fP by default never steps the system clock, because |
| any jump in the time can have adverse consequences for certain application |
| programs. Instead, any error in the system clock is corrected by slightly |
| speeding up or slowing down the system clock until the error has been removed, |
| and then returning to the system clock\(cqs normal speed. A consequence of this is |
| that there will be a period when the system clock (as read by other programs) |
| will be different from \fBchronyd\fP\(cqs estimate of the current true time (which it |
| reports to NTP clients when it is operating in server mode). The value reported |
| on this line is the difference due to this effect. |
| .RE |
| .sp |
| \fBLast offset\fP |
| .RS 4 |
| This is the estimated local offset on the last clock update. |
| .RE |
| .sp |
| \fBRMS offset\fP |
| .RS 4 |
| This is a long\-term average of the offset value. |
| .RE |
| .sp |
| \fBFrequency\fP |
| .RS 4 |
| The \(oqfrequency\(cq is the rate by which the system\(cqs clock would be wrong if |
| \fBchronyd\fP was not correcting it. It is expressed in ppm (parts per million). |
| For example, a value of 1 ppm would mean that when the system\(cqs clock thinks it |
| has advanced 1 second, it has actually advanced by 1.000001 seconds relative to |
| true time. |
| .RE |
| .sp |
| \fBResidual freq\fP |
| .RS 4 |
| This shows the \(oqresidual frequency\(cq for the currently selected reference |
| source. This reflects any difference between what the measurements from the |
| reference source indicate the frequency should be and the frequency currently |
| being used. |
| .sp |
| The reason this is not always zero is that a smoothing procedure is |
| applied to the frequency. Each time a measurement from the reference |
| source is obtained and a new residual frequency computed, the estimated |
| accuracy of this residual is compared with the estimated accuracy (see |
| \(oqskew\(cq next) of the existing frequency value. A weighted average is |
| computed for the new frequency, with weights depending on these accuracies. |
| If the measurements from the reference source follow a consistent trend, the |
| residual will be driven to zero over time. |
| .RE |
| .sp |
| \fBSkew\fP |
| .RS 4 |
| This is the estimated error bound on the frequency. |
| .RE |
| .sp |
| \fBRoot delay\fP |
| .RS 4 |
| This is the total of the network path delays to the stratum\-1 computer from |
| which the computer is ultimately synchronised. |
| .RE |
| .sp |
| \fBRoot dispersion\fP |
| .RS 4 |
| This is the total dispersion accumulated through all the computers back to |
| the stratum\-1 computer from which the computer is ultimately synchronised. |
| Dispersion is due to system clock resolution, statistical measurement |
| variations, etc. |
| .sp |
| An absolute bound on the computer\(cqs clock accuracy (assuming the stratum\-1 |
| computer is correct) is given by: |
| .sp |
| .if n \{\ |
| .RS 4 |
| .\} |
| .nf |
| clock_error <= |system_time_offset| + root_dispersion + (0.5 * root_delay) |
| .fi |
| .if n \{\ |
| .RE |
| .\} |
| .RE |
| .sp |
| \fBUpdate interval\fP |
| .RS 4 |
| This is the interval between the last two clock updates. |
| .RE |
| .sp |
| \fBLeap status\fP |
| .RS 4 |
| This is the leap status, which can be \fINormal\fP, \fIInsert second\fP, \fIDelete |
| second\fP or \fINot synchronised\fP. |
| .RE |
| .RE |
| .sp |
| \fBmakestep\fP, \fBmakestep\fP \fIthreshold\fP \fIlimit\fP |
| .RS 4 |
| Normally \fBchronyd\fP will cause the system to gradually correct any time offset, |
| by slowing down or speeding up the clock as required. In certain situations, |
| the system clock might be so far adrift that this slewing process would take a |
| very long time to correct the system clock. |
| .sp |
| The \fBmakestep\fP command can be used in this situation. There are two forms of |
| the command. The first form has no parameters. It tells \fBchronyd\fP to cancel any |
| remaining correction that was being slewed and jump the system clock by the |
| equivalent amount, making it correct immediately. |
| .sp |
| The second form configures the automatic stepping, similarly to the |
| \fBmakestep\fP directive. It has two parameters, |
| stepping threshold (in seconds) and number of future clock updates for which |
| the threshold will be active. This can be used with the \fBburst\fP |
| command to quickly make a new measurement and correct the clock by stepping if |
| needed, without waiting for \fBchronyd\fP to complete the measurement and update |
| the clock. |
| .sp |
| .if n \{\ |
| .RS 4 |
| .\} |
| .nf |
| makestep 0.1 1 |
| burst 1/2 |
| .fi |
| .if n \{\ |
| .RE |
| .\} |
| .sp |
| BE WARNED: Certain software will be seriously affected by such jumps in the |
| system time. (That is the reason why \fBchronyd\fP uses slewing normally.) |
| .RE |
| .sp |
| \fBmaxupdateskew\fP \fIskew\-in\-ppm\fP |
| .RS 4 |
| This command has the same effect as the |
| \fBmaxupdateskew\fP directive in the |
| configuration file. |
| .RE |
| .sp |
| \fBwaitsync\fP [\fImax\-tries\fP [\fImax\-correction\fP [\fImax\-skew\fP [\fIinterval\fP]]]] |
| .RS 4 |
| The \fBwaitsync\fP command waits for \fBchronyd\fP to synchronise. |
| .sp |
| Up to four optional arguments can be specified. The first is the maximum number |
| of tries before giving up and returning a non\-zero error code. When 0 is |
| specified, or there are no arguments, the number of tries will not be limited. |
| .sp |
| The second and third arguments are the maximum allowed remaining correction of |
| the system clock and the maximum allowed skew (in ppm) as reported by the |
| \fBtracking\fP command in the \fBSystem time\fP and \fBSkew\fP fields. If not |
| specified or zero, the value will not be checked. |
| .sp |
| The fourth argument is the interval specified in seconds in which the check is |
| repeated. The interval is 10 seconds by default. |
| .sp |
| An example is: |
| .sp |
| .if n \{\ |
| .RS 4 |
| .\} |
| .nf |
| waitsync 60 0.01 |
| .fi |
| .if n \{\ |
| .RE |
| .\} |
| .sp |
| which will wait up to about 10 minutes (60 times 10 seconds) for \fBchronyd\fP to |
| synchronise to a source and the remaining correction to be less than 10 |
| milliseconds. |
| .RE |
| .SS "Time sources" |
| .sp |
| \fBsources\fP [\fB\-v\fP] |
| .RS 4 |
| This command displays information about the current time sources that \fBchronyd\fP |
| is accessing. |
| .sp |
| The optional argument \fB\-v\fP can be specified, meaning \fIverbose\fP. In this case, |
| extra caption lines are shown as a reminder of the meanings of the columns. |
| .sp |
| .if n \{\ |
| .RS 4 |
| .\} |
| .nf |
| 210 Number of sources = 3 |
| MS Name/IP address Stratum Poll Reach LastRx Last sample |
| =============================================================================== |
| #* GPS0 0 4 377 11 \-479ns[ \-621ns] +/\- 134ns |
| ^? foo.example.net 2 6 377 23 \-923us[ \-924us] +/\- 43ms |
| ^+ bar.example.net 1 6 377 21 \-2629us[\-2619us] +/\- 86ms |
| .fi |
| .if n \{\ |
| .RE |
| .\} |
| .sp |
| The columns are as follows: |
| .sp |
| \fBM\fP |
| .RS 4 |
| This indicates the mode of the source. \fI^\fP means a server, \fI=\fP means a peer |
| and \fI#\fP indicates a locally connected reference clock. |
| .RE |
| .sp |
| \fBS\fP |
| .RS 4 |
| This column indicates the state of the source. |
| .sp |
| .RS 4 |
| .ie n \{\ |
| \h'-04'\(bu\h'+03'\c |
| .\} |
| .el \{\ |
| .sp -1 |
| .IP \(bu 2.3 |
| .\} |
| \fI*\fP indicates the source to which \fBchronyd\fP is currently synchronised. |
| .RE |
| .sp |
| .RS 4 |
| .ie n \{\ |
| \h'-04'\(bu\h'+03'\c |
| .\} |
| .el \{\ |
| .sp -1 |
| .IP \(bu 2.3 |
| .\} |
| \fI+\fP indicates acceptable sources which are combined with the selected |
| source. |
| .RE |
| .sp |
| .RS 4 |
| .ie n \{\ |
| \h'-04'\(bu\h'+03'\c |
| .\} |
| .el \{\ |
| .sp -1 |
| .IP \(bu 2.3 |
| .\} |
| \fI\-\fP indicates acceptable sources which are excluded by the combining |
| algorithm. |
| .RE |
| .sp |
| .RS 4 |
| .ie n \{\ |
| \h'-04'\(bu\h'+03'\c |
| .\} |
| .el \{\ |
| .sp -1 |
| .IP \(bu 2.3 |
| .\} |
| \fI?\fP indicates sources to which connectivity has been lost or whose packets |
| do not pass all tests. It is also shown at start\-up, until at least 3 samples |
| have been gathered from it. |
| .RE |
| .sp |
| .RS 4 |
| .ie n \{\ |
| \h'-04'\(bu\h'+03'\c |
| .\} |
| .el \{\ |
| .sp -1 |
| .IP \(bu 2.3 |
| .\} |
| \fIx\fP indicates a clock which \fBchronyd\fP thinks is a falseticker (i.e. its |
| time is inconsistent with a majority of other sources). |
| .RE |
| .sp |
| .RS 4 |
| .ie n \{\ |
| \h'-04'\(bu\h'+03'\c |
| .\} |
| .el \{\ |
| .sp -1 |
| .IP \(bu 2.3 |
| .\} |
| \fI~\fP indicates a source whose time appears to have too much variability. |
| .RE |
| .RE |
| .sp |
| \fBName/IP address\fP |
| .RS 4 |
| This shows the name or the IP address of the source, or reference ID for reference |
| clocks. |
| .RE |
| .sp |
| \fBStratum\fP |
| .RS 4 |
| This shows the stratum of the source, as reported in its most recently |
| received sample. Stratum 1 indicates a computer with a locally attached |
| reference clock. A computer that is synchronised to a stratum 1 computer is |
| at stratum 2. A computer that is synchronised to a stratum 2 computer is at |
| stratum 3, and so on. |
| .RE |
| .sp |
| \fBPoll\fP |
| .RS 4 |
| This shows the rate at which the source is being polled, as a base\-2 |
| logarithm of the interval in seconds. Thus, a value of 6 would indicate that |
| a measurement is being made every 64 seconds. \fBchronyd\fP automatically varies |
| the polling rate in response to prevailing conditions. |
| .RE |
| .sp |
| \fBReach\fP |
| .RS 4 |
| This shows the source\(cqs reachability register printed as an octal number. The |
| register has 8 bits and is updated on every received or missed packet from |
| the source. A value of 377 indicates that a valid reply was received for all |
| from the last eight transmissions. |
| .RE |
| .sp |
| \fBLastRx\fP |
| .RS 4 |
| This column shows how long ago the last sample was received from the source. |
| This is normally in seconds. The letters \fIm\fP, \fIh\fP, \fId\fP or \fIy\fP indicate |
| minutes, hours, days, or years. |
| .RE |
| .sp |
| \fBLast sample\fP |
| .RS 4 |
| This column shows the offset between the local clock and the source at the |
| last measurement. The number in the square brackets shows the actual measured |
| offset. This can be suffixed by \fIns\fP (indicating nanoseconds), \fIus\fP |
| (indicating microseconds), \fIms\fP (indicating milliseconds), or \fIs\fP (indicating |
| seconds). The number to the left of the square brackets shows the original |
| measurement, adjusted to allow for any slews applied to the local clock |
| since. The number following the \fI+/\-\fP indicator shows the margin of error in |
| the measurement. Positive offsets indicate that the local clock is ahead of |
| the source. |
| .RE |
| .RE |
| .sp |
| \fBsourcestats\fP [\fB\-v\fP] |
| .RS 4 |
| The \fBsourcestats\fP command displays information about the drift rate and offset |
| estimation process for each of the sources currently being examined by |
| \fBchronyd\fP. |
| .sp |
| The optional argument \fB\-v\fP can be specified, meaning \fIverbose\fP. In this case, |
| extra caption lines are shown as a reminder of the meanings of the columns. |
| .sp |
| An example report is: |
| .sp |
| .if n \{\ |
| .RS 4 |
| .\} |
| .nf |
| 210 Number of sources = 1 |
| Name/IP Address NP NR Span Frequency Freq Skew Offset Std Dev |
| =============================================================================== |
| foo.example.net 11 5 46m \-0.001 0.045 1us 25us |
| .fi |
| .if n \{\ |
| .RE |
| .\} |
| .sp |
| The columns are as follows: |
| .sp |
| \fBName/IP Address\fP |
| .RS 4 |
| This is the name or IP address of the NTP server (or peer) or reference ID of the |
| reference clock to which the rest of the line relates. |
| .RE |
| .sp |
| \fBNP\fP |
| .RS 4 |
| This is the number of sample points currently being retained for the server. |
| The drift rate and current offset are estimated by performing a linear |
| regression through these points. |
| .RE |
| .sp |
| \fBNR\fP |
| .RS 4 |
| This is the number of runs of residuals having the same sign following the |
| last regression. If this number starts to become too small relative to the |
| number of samples, it indicates that a straight line is no longer a good fit |
| to the data. If the number of runs is too low, \fBchronyd\fP discards older |
| samples and re\-runs the regression until the number of runs becomes |
| acceptable. |
| .RE |
| .sp |
| \fBSpan\fP |
| .RS 4 |
| This is the interval between the oldest and newest samples. If no unit is |
| shown the value is in seconds. In the example, the interval is 46 minutes. |
| .RE |
| .sp |
| \fBFrequency\fP |
| .RS 4 |
| This is the estimated residual frequency for the server, in parts per |
| million. In this case, the computer\(cqs clock is estimated to be running 1 part |
| in 10^9 slow relative to the server. |
| .RE |
| .sp |
| \fBFreq Skew\fP |
| .RS 4 |
| This is the estimated error bounds on \fBFreq\fP (again in parts per million). |
| .RE |
| .sp |
| \fBOffset\fP |
| .RS 4 |
| This is the estimated offset of the source. |
| .RE |
| .sp |
| \fBStd Dev\fP |
| .RS 4 |
| This is the estimated sample standard deviation. |
| .RE |
| .RE |
| .sp |
| \fBreselect\fP |
| .RS 4 |
| To avoid excessive switching between sources, \fBchronyd\fP can stay synchronised |
| to a source even when it is not currently the best one among the available |
| sources. |
| .sp |
| The \fBreselect\fP command can be used to force \fBchronyd\fP to reselect the best |
| synchronisation source. |
| .RE |
| .sp |
| \fBreselectdist\fP \fIdistance\fP |
| .RS 4 |
| The \fBreselectdist\fP command sets the reselection distance. It is equivalent to |
| the \fBreselectdist\fP directive in the |
| configuration file. |
| .RE |
| .SS "NTP sources" |
| .sp |
| \fBactivity\fP |
| .RS 4 |
| This command reports the number of servers and peers that are online and |
| offline. If the \fBauto_offline\fP option is used in specifying some of the servers |
| or peers, the \fBactivity\fP command can be useful for detecting when all of them |
| have entered the offline state after the network link has been disconnected. |
| .sp |
| The report shows the number of servers and peers in 5 states: |
| .sp |
| \fBonline\fP |
| .RS 4 |
| the server or peer is currently online (i.e. assumed by \fBchronyd\fP to be reachable) |
| .RE |
| .sp |
| \fBoffline\fP |
| .RS 4 |
| the server or peer is currently offline (i.e. assumed by \fBchronyd\fP to be |
| unreachable, and no measurements from it will be attempted.) |
| .RE |
| .sp |
| \fBburst_online\fP |
| .RS 4 |
| a burst command has been initiated for the server or peer and is being |
| performed; after the burst is complete, the server or peer will be returned to |
| the online state. |
| .RE |
| .sp |
| \fBburst_offline\fP |
| .RS 4 |
| a burst command has been initiated for the server or peer and is being |
| performed; after the burst is complete, the server or peer will be returned to |
| the offline state. |
| .RE |
| .sp |
| \fBunresolved\fP |
| .RS 4 |
| the name of the server or peer was not resolved to an address yet; this source is |
| not visible in the \fBsources\fP and \fBsourcestats\fP reports. |
| .RE |
| .RE |
| .sp |
| \fBntpdata\fP [\fIaddress\fP] |
| .RS 4 |
| The \fBntpdata\fP command displays the last valid measurement and other |
| NTP\-specific information about the specified NTP source, or all NTP sources if |
| no address was specified. An example of the output is shown below. |
| .sp |
| .if n \{\ |
| .RS 4 |
| .\} |
| .nf |
| Remote address : 203.0.113.15 (CB00710F) |
| Remote port : 123 |
| Local address : 203.0.113.74 (CB00714A) |
| Leap status : Normal |
| Version : 4 |
| Mode : Server |
| Stratum : 1 |
| Poll interval : 10 (1024 seconds) |
| Precision : \-24 (0.000000060 seconds) |
| Root delay : 0.000015 seconds |
| Root dispersion : 0.000015 seconds |
| Reference ID : 47505300 (GPS) |
| Reference time : Fri Nov 25 15:22:12 2016 |
| Offset : \-0.000060878 seconds |
| Peer delay : 0.000175634 seconds |
| Peer dispersion : 0.000000681 seconds |
| Response time : 0.000053050 seconds |
| Jitter asymmetry: +0.00 |
| NTP tests : 111 111 1111 |
| Interleaved : No |
| Authenticated : No |
| TX timestamping : Kernel |
| RX timestamping : Kernel |
| Total TX : 24 |
| Total RX : 24 |
| Total valid RX : 24 |
| .fi |
| .if n \{\ |
| .RE |
| .\} |
| .sp |
| The fields are explained as follows: |
| .sp |
| \fBRemote address\fP |
| .RS 4 |
| The IP address of the NTP server or peer, and the corresponding reference ID. |
| .RE |
| .sp |
| \fBRemote port\fP |
| .RS 4 |
| The UDP port number to which the request was sent. The standard NTP port is |
| 123. |
| .RE |
| .sp |
| \fBLocal address\fP |
| .RS 4 |
| The local IP address which received the response, and the corresponding |
| reference ID. |
| .RE |
| .sp |
| \fBLeap status\fP, \fBVersion\fP, \fBMode\fP, \fBStratum\fP, \fBPoll interval\fP, \fBPrecision\fP, \fBRoot delay\fP, \fBRoot dispersion\fP, \fBReference ID\fP, \fBReference time\fP |
| .RS 4 |
| The NTP values from the last valid response. |
| .RE |
| .sp |
| \fBOffset\fP, \fBPeer delay\fP, \fBPeer dispersion\fP |
| .RS 4 |
| The measured values. |
| .RE |
| .sp |
| \fBResponse time\fP |
| .RS 4 |
| The time the server or peer spent in processing of the request and waiting |
| before sending the response. |
| .RE |
| .sp |
| \fBJitter asymmetry\fP |
| .RS 4 |
| The estimated asymmetry of network jitter on the path to the source. The |
| asymmetry can be between \-0.5 and 0.5. A negative value means the delay of |
| packets sent to the source is more variable than the delay of packets sent |
| from the source back. |
| .RE |
| .sp |
| \fBNTP tests\fP |
| .RS 4 |
| Results of RFC 5905 tests 1 through 3, 5 through 7, and tests for maximum |
| delay, delay ratio, delay dev ratio, and synchronisation loop. |
| .RE |
| .sp |
| \fBInterleaved\fP |
| .RS 4 |
| This shows if the response was in the interleaved mode. |
| .RE |
| .sp |
| \fBAuthenticated\fP |
| .RS 4 |
| This shows if the response was authenticated. |
| .RE |
| .sp |
| \fBTX timestamping\fP |
| .RS 4 |
| The source of the local transmit timestamp. Valid values are \fIDaemon\fP, |
| \fIKernel\fP, and \fIHardware\fP. |
| .RE |
| .sp |
| \fBRX timestamping\fP |
| .RS 4 |
| The source of the local receive timestamp. |
| .RE |
| .sp |
| \fBTotal TX\fP |
| .RS 4 |
| The number of packets sent to the source. |
| .RE |
| .sp |
| \fBTotal RX\fP |
| .RS 4 |
| The number of all packets received from the source. |
| .RE |
| .sp |
| \fBTotal valid RX\fP |
| .RS 4 |
| The number of valid packets received from the source. |
| .RE |
| .RE |
| .sp |
| \fBadd peer\fP \fIaddress\fP [\fIoption\fP]... |
| .RS 4 |
| The \fBadd peer\fP command allows a new NTP peer to be added whilst |
| \fBchronyd\fP is running. |
| .sp |
| Following the words \fBadd peer\fP, the syntax of the following |
| parameters and options is similar to that for the |
| \fBpeer\fP directive in the configuration file. |
| The following peer options can be set in the command: \fBport\fP, \fBminpoll\fP, |
| \fBmaxpoll\fP, \fBpresend\fP, \fBmaxdelayratio\fP, \fBmaxdelay\fP, \fBkey\fP. |
| .sp |
| An example of using this command is shown below. |
| .sp |
| .if n \{\ |
| .RS 4 |
| .\} |
| .nf |
| add peer foo.example.net minpoll 6 maxpoll 10 key 25 |
| .fi |
| .if n \{\ |
| .RE |
| .\} |
| .RE |
| .sp |
| \fBadd server\fP \fIaddress\fP [\fIoption\fP]... |
| .RS 4 |
| The \fBadd server\fP command allows a new NTP server to be added whilst |
| \fBchronyd\fP is running. |
| .sp |
| Following the words \fBadd server\fP, the syntax of the following parameters and |
| options is similar to that for the \fBserver\fP |
| directive in the configuration file. |
| The following server options can be set in the command: \fBport\fP, \fBminpoll\fP, |
| \fBmaxpoll\fP, \fBpresend\fP, \fBmaxdelayratio\fP, \fBmaxdelay\fP, \fBkey\fP. |
| .sp |
| An example of using this command is shown below: |
| .sp |
| .if n \{\ |
| .RS 4 |
| .\} |
| .nf |
| add server foo.example.net minpoll 6 maxpoll 10 key 25 |
| .fi |
| .if n \{\ |
| .RE |
| .\} |
| .RE |
| .sp |
| \fBdelete\fP \fIaddress\fP |
| .RS 4 |
| The \fBdelete\fP command allows an NTP server or peer to be removed |
| from the current set of sources. |
| .RE |
| .sp |
| \fBburst\fP \fIgood\fP/\fImax\fP [\fImask\fP/\fImasked\-address\fP], \fBburst\fP \fIgood\fP/\fImax\fP [\fImasked\-address\fP/\fImasked\-bits\fP], \fBburst\fP \fIgood\fP/\fImax\fP [\fIaddress\fP] |
| .RS 4 |
| The \fBburst\fP command tells \fBchronyd\fP to make a set of measurements to each of |
| its NTP sources over a short duration (rather than the usual periodic |
| measurements that it makes). After such a burst, \fBchronyd\fP will revert to the |
| previous state for each source. This might be either online, if the source was |
| being periodically measured in the normal way, or offline, if the source had |
| been indicated as being offline. (A source can be switched between the online |
| and offline states with the \fBonline\fP and \fBoffline\fP |
| commands.) |
| .sp |
| The \fImask\fP and \fImasked\-address\fP arguments are optional, in which case \fBchronyd\fP |
| will initiate a burst for all of its currently defined sources. |
| .sp |
| The arguments have the following meaning and format: |
| .sp |
| \fIgood\fP |
| .RS 4 |
| This defines the number of good measurements that \fBchronyd\fP will want to |
| obtain from each source. A measurement is good if it passes certain tests, |
| for example, the round trip time to the source must be acceptable. (This |
| allows \fBchronyd\fP to reject measurements that are likely to be bogus.) |
| .RE |
| .sp |
| \fImax\fP |
| .RS 4 |
| This defines the maximum number of measurements that \fBchronyd\fP will attempt |
| to make, even if the required number of good measurements has not been |
| obtained. |
| .RE |
| .sp |
| \fImask\fP |
| .RS 4 |
| This is an IP address with which the IP address of each of \fBchronyd\fP\(cqs |
| sources is to be masked. |
| .RE |
| .sp |
| \fImasked\-address\fP |
| .RS 4 |
| This is an IP address. If the masked IP address of a source matches this |
| value then the burst command is applied to that source. |
| .RE |
| .sp |
| \fImasked\-bits\fP |
| .RS 4 |
| This can be used with \fImasked\-address\fP for CIDR notation, which is a shorter |
| alternative to the form with mask. |
| .RE |
| .sp |
| \fIaddress\fP |
| .RS 4 |
| This is an IP address or a hostname. The burst command is applied only to |
| that source. |
| .RE |
| .RE |
| .sp |
| |
| .RS 4 |
| .sp |
| If no \fImask\fP or \fImasked\-address\fP arguments are provided, every source will be |
| matched. |
| .sp |
| An example of the two\-argument form of the command is: |
| .sp |
| .if n \{\ |
| .RS 4 |
| .\} |
| .nf |
| burst 2/10 |
| .fi |
| .if n \{\ |
| .RE |
| .\} |
| .sp |
| This will cause \fBchronyd\fP to attempt to get two good measurements from each |
| source, stopping after two have been obtained, but in no event will it try more |
| than ten probes to the source. |
| .sp |
| Examples of the four\-argument form of the command are: |
| .sp |
| .if n \{\ |
| .RS 4 |
| .\} |
| .nf |
| burst 2/10 255.255.0.0/1.2.0.0 |
| burst 2/10 2001:db8:789a::/48 |
| .fi |
| .if n \{\ |
| .RE |
| .\} |
| .sp |
| In the first case, the two out of ten sampling will only be applied to sources |
| whose IPv4 addresses are of the form \fI1.2.x.y\fP, where \fIx\fP and \fIy\fP are |
| arbitrary. In the second case, the sampling will be applied to sources whose |
| IPv6 addresses have first 48 bits equal to \fI2001:db8:789a\fP. |
| .sp |
| Example of the three\-argument form of the command is: |
| .sp |
| .if n \{\ |
| .RS 4 |
| .\} |
| .nf |
| burst 2/10 foo.example.net |
| .fi |
| .if n \{\ |
| .RE |
| .\} |
| .RE |
| .sp |
| \fBmaxdelay\fP \fIaddress\fP \fIdelay\fP |
| .RS 4 |
| This allows the \fBmaxdelay\fP option for one of the sources to be modified, in the |
| same way as specifying the \fBmaxdelay\fP option for the |
| \fBserver\fP directive in the configuration file. |
| .RE |
| .sp |
| \fBmaxdelaydevratio\fP \fIaddress\fP \fIratio\fP |
| .RS 4 |
| This allows the \fBmaxdelaydevratio\fP option for one of the sources to be |
| modified, in the same way as specifying the \fBmaxdelaydevratio\fP option for the |
| \fBserver\fP directive in the configuration file. |
| .RE |
| .sp |
| \fBmaxdelayratio\fP \fIaddress\fP \fIratio\fP |
| .RS 4 |
| This allows the \fBmaxdelayratio\fP option for one of the sources to be modified, |
| in the same way as specifying the \fBmaxdelayratio\fP option for the |
| \fBserver\fP directive in the configuration file. |
| .RE |
| .sp |
| \fBmaxpoll\fP \fIaddress\fP \fImaxpoll\fP |
| .RS 4 |
| The \fBmaxpoll\fP command is used to modify the maximum polling interval for one of |
| the current set of sources. It is equivalent to the \fBmaxpoll\fP option in the |
| \fBserver\fP directive in the configuration file. |
| .sp |
| Note that the new maximum polling interval only takes effect after the next |
| measurement has been made. |
| .RE |
| .sp |
| \fBminpoll\fP \fIaddress\fP \fIminpoll\fP |
| .RS 4 |
| The \fBminpoll\fP command is used to modify the minimum polling interval for one of |
| the current set of sources. It is equivalent to the \fBminpoll\fP option in the |
| \fBserver\fP directive in the configuration file. |
| .sp |
| Note that the new minimum polling interval only takes effect after the next |
| measurement has been made. |
| .RE |
| .sp |
| \fBminstratum\fP \fIaddress\fP \fIminstratum\fP |
| .RS 4 |
| The \fBminstratum\fP command is used to modify the minimum stratum for one of the |
| current set of sources. It is equivalent to the \fBminstratum\fP option in the |
| \fBserver\fP directive in the configuration file. |
| .RE |
| .sp |
| \fBoffline\fP [\fIaddress\fP], \fBoffline\fP [\fImasked\-address\fP/\fImasked\-bits\fP], \fBoffline\fP [\fImask\fP/\fImasked\-address\fP] |
| .RS 4 |
| The \fBoffline\fP command is used to warn \fBchronyd\fP that the network connection to |
| a particular host or hosts is about to be lost, e.g. on computers with |
| intermittent connection to their time sources. |
| .sp |
| Another case where \fBoffline\fP could be used is where a computer serves time to a |
| local group of computers, and has a permanent connection to true time servers |
| outside the organisation. However, the external connection is heavily loaded at |
| certain times of the day and the measurements obtained are less reliable at |
| those times. In this case, it is probably most useful to determine the |
| gain or loss rate during the quiet periods and let the whole network coast through |
| the loaded periods. The \fBoffline\fP and \fBonline\fP commands can be used to achieve |
| this. |
| .sp |
| There are four forms of the \fBoffline\fP command. The first form is a wildcard, |
| meaning all sources. The second form allows an IP address mask and a masked |
| address to be specified. The third form uses CIDR notation. The fourth form |
| uses an IP address or a hostname. These forms are illustrated below. |
| .sp |
| .if n \{\ |
| .RS 4 |
| .\} |
| .nf |
| offline |
| offline 255.255.255.0/1.2.3.0 |
| offline 2001:db8:789a::/48 |
| offline foo.example.net |
| .fi |
| .if n \{\ |
| .RE |
| .\} |
| .sp |
| The second form means that the \fBoffline\fP command is to be applied to any source |
| whose IPv4 address is in the \fI1.2.3\fP subnet. (The host\(cqs address is logically |
| and\-ed with the mask, and if the result matches the \fImasked\-address\fP the host |
| is processed.) The third form means that the command is to be applied to all |
| sources whose IPv6 addresses have their first 48 bits equal to \fI2001:db8:789a\fP. The |
| fourth form means that the command is to be applied only to that one source. |
| .sp |
| The wildcard form of the address is equivalent to: |
| .sp |
| .if n \{\ |
| .RS 4 |
| .\} |
| .nf |
| offline 0.0.0.0/0.0.0.0 |
| offline ::/0 |
| .fi |
| .if n \{\ |
| .RE |
| .\} |
| .RE |
| .sp |
| \fBonline\fP [\fIaddress\fP], \fBonline\fP [\fImasked\-address\fP/\fImasked\-bits\fP], \fBonline\fP [\fImask\fP/\fImasked\-address\fP] |
| .RS 4 |
| The \fBonline\fP command is opposite in function to the \fBoffline\fP |
| command. It is used to advise \fBchronyd\fP that network connectivity to a |
| particular source or sources has been restored. |
| .sp |
| The syntax is identical to that of the \fBoffline\fP command. |
| .RE |
| .sp |
| \fBpolltarget\fP \fIaddress\fP \fIpolltarget\fP |
| .RS 4 |
| The \fBpolltarget\fP command is used to modify the poll target for one of the |
| current set of sources. It is equivalent to the \fBpolltarget\fP option in the |
| \fBserver\fP directive in the configuration file. |
| .RE |
| .sp |
| \fBrefresh\fP |
| .RS 4 |
| The \fBrefresh\fP command can be used to force \fBchronyd\fP to resolve the names of |
| configured sources to IP addresses again, e.g. after suspending and resuming |
| the machine in a different network. |
| .sp |
| Sources that stop responding will be replaced with newly resolved addresses |
| automatically after 8 polling intervals, but this command can still be useful |
| to replace them immediately and not wait until they are marked as unreachable. |
| .RE |
| .SS "Manual time input" |
| .sp |
| \fBmanual\fP \fBon\fP, \fBmanual\fP \fBoff\fP, \fBmanual\fP \fBdelete\fP \fIindex\fP, \fBmanual\fP \fBlist\fP, \fBmanual\fP \fBreset\fP |
| .RS 4 |
| The manual command enables and disables use of the \fBsettime\fP |
| command, and is used to modify the behaviour of the manual clock driver. |
| .sp |
| The \fBon\fP form of the command enables use of the \fBsettime\fP command. |
| .sp |
| The \fBoff\fP form of the command disables use of the \fBsettime\fP command. |
| .sp |
| The \fBlist\fP form of the command lists all the samples currently stored in |
| \fBchronyd\fP. The output is illustrated below. |
| .sp |
| .if n \{\ |
| .RS 4 |
| .\} |
| .nf |
| 210 n_samples = 1 |
| # Date Time(UTC) Slewed Original Residual |
| ==================================================== |
| 0 27Jan99 22:09:20 0.00 0.97 0.00 |
| .fi |
| .if n \{\ |
| .RE |
| .\} |
| .sp |
| The columns are as as follows: |
| .sp |
| .RS 4 |
| .ie n \{\ |
| \h'-04' 1.\h'+01'\c |
| .\} |
| .el \{\ |
| .sp -1 |
| .IP " 1." 4.2 |
| .\} |
| The sample index (used for the \fBmanual delete\fP command). |
| .RE |
| .sp |
| .RS 4 |
| .ie n \{\ |
| \h'-04' 2.\h'+01'\c |
| .\} |
| .el \{\ |
| .sp -1 |
| .IP " 2." 4.2 |
| .\} |
| The date and time of the sample. |
| .RE |
| .sp |
| .RS 4 |
| .ie n \{\ |
| \h'-04' 3.\h'+01'\c |
| .\} |
| .el \{\ |
| .sp -1 |
| .IP " 3." 4.2 |
| .\} |
| The system clock error when the timestamp was entered, adjusted to allow |
| for changes made to the system clock since. |
| .RE |
| .sp |
| .RS 4 |
| .ie n \{\ |
| \h'-04' 4.\h'+01'\c |
| .\} |
| .el \{\ |
| .sp -1 |
| .IP " 4." 4.2 |
| .\} |
| The system clock error when the timestamp was entered, as it originally was |
| (without allowing for changes to the system clock since). |
| .RE |
| .sp |
| .RS 4 |
| .ie n \{\ |
| \h'-04' 5.\h'+01'\c |
| .\} |
| .el \{\ |
| .sp -1 |
| .IP " 5." 4.2 |
| .\} |
| The regression residual at this point, in seconds. This allows \(oqoutliers\(cq |
| to be easily spotted, so that they can be deleted using the \fBmanual delete\fP |
| command. |
| .RE |
| .RE |
| .sp |
| |
| .RS 4 |
| .sp |
| The \fBdelete\fP form of the command deletes a single sample. The parameter is the |
| index of the sample, as shown in the first column of the output from \fBmanual |
| list\fP. Following deletion of the data point, the current error and drift rate |
| are re\-estimated from the remaining data points and the system clock trimmed if |
| necessary. This option is intended to allow \(oqoutliers\(cq to be discarded, i.e. |
| samples where the administrator realises they have entered a very poor |
| timestamp. |
| .sp |
| The \fBreset\fP form of the command deletes all samples at once. The system clock |
| is left running as it was before the command was entered. |
| .RE |
| .sp |
| \fBsettime\fP \fItime\fP |
| .RS 4 |
| The \fBsettime\fP command allows the current time to be entered manually, if this |
| option has been configured into \fBchronyd\fP. (It can be configured either with |
| the \fBmanual\fP directive in the configuration file, |
| or with the \fBmanual\fP command of \fBchronyc\fP.) |
| .sp |
| It should be noted that the computer\(cqs sense of time will only be as accurate |
| as the reference you use for providing this input (e.g. your watch), as well as |
| how well you can time the press of the return key. |
| .sp |
| Providing your computer\(cqs time zone is set up properly, you will be able to |
| enter a local time (rather than UTC). |
| .sp |
| The response to a successful \fBsettime\fP command indicates the amount that the |
| computer\(cqs clock was wrong. It should be apparent from this if you have entered |
| the time wrongly, e.g. with the wrong time zone. |
| .sp |
| The rate of drift of the system clock is estimated by a regression process |
| using the entered measurement and all previous measurements entered during the |
| present run of \fBchronyd\fP. However, the entered measurement is used for |
| adjusting the current clock offset (rather than the estimated intercept from |
| the regression, which is ignored). Contrast what happens with the |
| \fBmanual delete\fP command, where the intercept is used to set the |
| current offset (since there is no measurement that has just been entered in |
| that case). |
| .sp |
| The time is parsed by the public domain \fIgetdate\fP algorithm. Consequently, you |
| can only specify time to the nearest second. |
| .sp |
| Examples of inputs that are valid are shown below: |
| .sp |
| .if n \{\ |
| .RS 4 |
| .\} |
| .nf |
| settime 16:30 |
| settime 16:30:05 |
| settime Nov 21, 2015 16:30:05 |
| .fi |
| .if n \{\ |
| .RE |
| .\} |
| .sp |
| For a full description of getdate, see the getdate documentation |
| (bundled, for example, with the source for GNU tar). |
| .RE |
| .SS "NTP access" |
| .sp |
| \fBaccheck\fP \fIaddress\fP |
| .RS 4 |
| This command allows you to check whether client NTP access is allowed from a |
| particular host. |
| .sp |
| Examples of use, showing a named host and a numeric IP address, are as follows: |
| .sp |
| .if n \{\ |
| .RS 4 |
| .\} |
| .nf |
| accheck foo.example.net |
| accheck 1.2.3.4 |
| accheck 2001:db8::1 |
| .fi |
| .if n \{\ |
| .RE |
| .\} |
| .sp |
| This command can be used to examine the effect of a series of \fBallow\fP, \fBallow |
| all\fP, \fBdeny\fP, and \fBdeny all\fP commands specified either via \fBchronyc\fP, or in |
| \fBchronyd\fP\(cqs configuration file. |
| .RE |
| .sp |
| \fBclients\fP |
| .RS 4 |
| This command shows a list of clients that have accessed the server, through |
| either the NTP or command ports. It does not include accesses over |
| the Unix domain command socket. There are no arguments. |
| .sp |
| An example of the output is: |
| .sp |
| .if n \{\ |
| .RS 4 |
| .\} |
| .nf |
| Hostname NTP Drop Int IntL Last Cmd Drop Int Last |
| =============================================================================== |
| localhost 2 0 2 \- 133 15 0 \-1 7 |
| foo.example.net 12 0 6 \- 23 0 0 \- \- |
| .fi |
| .if n \{\ |
| .RE |
| .\} |
| .sp |
| Each row shows the data for a single host. Only hosts that have passed the host |
| access checks (set with the \fBallow\fP, \fBdeny\fP, |
| \fBcmdallow\fP and \fBcmddeny\fP commands or configuration |
| file directives) are logged. The intervals are displayed as a power of 2 in |
| seconds. |
| .sp |
| The columns are as follows: |
| .sp |
| .RS 4 |
| .ie n \{\ |
| \h'-04' 1.\h'+01'\c |
| .\} |
| .el \{\ |
| .sp -1 |
| .IP " 1." 4.2 |
| .\} |
| The hostname of the client. |
| .RE |
| .sp |
| .RS 4 |
| .ie n \{\ |
| \h'-04' 2.\h'+01'\c |
| .\} |
| .el \{\ |
| .sp -1 |
| .IP " 2." 4.2 |
| .\} |
| The number of NTP packets received from the client. |
| .RE |
| .sp |
| .RS 4 |
| .ie n \{\ |
| \h'-04' 3.\h'+01'\c |
| .\} |
| .el \{\ |
| .sp -1 |
| .IP " 3." 4.2 |
| .\} |
| The number of NTP packets dropped to limit the response rate. |
| .RE |
| .sp |
| .RS 4 |
| .ie n \{\ |
| \h'-04' 4.\h'+01'\c |
| .\} |
| .el \{\ |
| .sp -1 |
| .IP " 4." 4.2 |
| .\} |
| The average interval between NTP packets. |
| .RE |
| .sp |
| .RS 4 |
| .ie n \{\ |
| \h'-04' 5.\h'+01'\c |
| .\} |
| .el \{\ |
| .sp -1 |
| .IP " 5." 4.2 |
| .\} |
| The average interval between NTP packets after limiting the response rate. |
| .RE |
| .sp |
| .RS 4 |
| .ie n \{\ |
| \h'-04' 6.\h'+01'\c |
| .\} |
| .el \{\ |
| .sp -1 |
| .IP " 6." 4.2 |
| .\} |
| Time since the last NTP packet was received |
| .RE |
| .sp |
| .RS 4 |
| .ie n \{\ |
| \h'-04' 7.\h'+01'\c |
| .\} |
| .el \{\ |
| .sp -1 |
| .IP " 7." 4.2 |
| .\} |
| The number of command packets received from the client. |
| .RE |
| .sp |
| .RS 4 |
| .ie n \{\ |
| \h'-04' 8.\h'+01'\c |
| .\} |
| .el \{\ |
| .sp -1 |
| .IP " 8." 4.2 |
| .\} |
| The number of command packets dropped to limit the response rate. |
| .RE |
| .sp |
| .RS 4 |
| .ie n \{\ |
| \h'-04' 9.\h'+01'\c |
| .\} |
| .el \{\ |
| .sp -1 |
| .IP " 9." 4.2 |
| .\} |
| The average interval between command packets. |
| .RE |
| .sp |
| .RS 4 |
| .ie n \{\ |
| \h'-04' 10.\h'+01'\c |
| .\} |
| .el \{\ |
| .sp -1 |
| .IP " 10." 4.2 |
| .\} |
| Time since the last command packet was received. |
| .RE |
| .RE |
| .sp |
| \fBserverstats\fP |
| .RS 4 |
| The \fBserverstats\fP command displays how many valid NTP and command requests |
| \fBchronyd\fP as a server received from clients, how many of them were dropped to |
| limit the response rate as configured by the |
| \fBratelimit\fP and |
| \fBcmdratelimit\fP directives, and how many |
| client log records were dropped due to the memory limit configured by the |
| \fBclientloglimit\fP directive. An example of |
| the output is shown below. |
| .sp |
| .if n \{\ |
| .RS 4 |
| .\} |
| .nf |
| NTP packets received : 1598 |
| NTP packets dropped : 8 |
| Command packets received : 19 |
| Command packets dropped : 0 |
| Client log records dropped : 0 |
| .fi |
| .if n \{\ |
| .RE |
| .\} |
| .RE |
| .sp |
| \fBallow\fP [\fBall\fP] [\fIsubnet\fP] |
| .RS 4 |
| The effect of the allow command is identical to the |
| \fBallow\fP directive in the configuration file. |
| .sp |
| The syntax is illustrated in the following examples: |
| .sp |
| .if n \{\ |
| .RS 4 |
| .\} |
| .nf |
| allow foo.example.net |
| allow all 1.2 |
| allow 3.4.5 |
| allow 6.7.8/22 |
| allow 6.7.8.9/22 |
| allow 2001:db8:789a::/48 |
| allow 0/0 |
| allow ::/0 |
| allow |
| allow all |
| .fi |
| .if n \{\ |
| .RE |
| .\} |
| .RE |
| .sp |
| \fBdeny\fP [\fBall\fP] [\fIsubnet\fP] |
| .RS 4 |
| The effect of the allow command is identical to the |
| \fBdeny\fP directive in the configuration file. |
| .sp |
| The syntax is illustrated in the following examples: |
| .sp |
| .if n \{\ |
| .RS 4 |
| .\} |
| .nf |
| deny foo.example.net |
| deny all 1.2 |
| deny 3.4.5 |
| deny 6.7.8/22 |
| deny 6.7.8.9/22 |
| deny 2001:db8:789a::/48 |
| deny 0/0 |
| deny ::/0 |
| deny |
| deny all |
| .fi |
| .if n \{\ |
| .RE |
| .\} |
| .RE |
| .sp |
| \fBlocal\fP [\fIoption\fP]..., \fBlocal\fP \fBoff\fP |
| .RS 4 |
| The \fBlocal\fP command allows \fBchronyd\fP to be told that it is to appear as a |
| reference source, even if it is not itself properly synchronised to an external |
| source. (This can be used on isolated networks, to allow one computer to be a |
| master time server with the other computers slaving to it.) |
| .sp |
| The first form enables the local reference mode on the host. The syntax is |
| identical to the \fBlocal\fP directive in the |
| configuration file. |
| .sp |
| The second form disables the local reference mode. |
| .RE |
| .sp |
| \fBsmoothing\fP |
| .RS 4 |
| The \fBsmoothing\fP command displays the current state of the NTP server time |
| smoothing, which can be enabled with the |
| \fBsmoothtime\fP directive. An example of the |
| output is shown below. |
| .sp |
| .if n \{\ |
| .RS 4 |
| .\} |
| .nf |
| Active : Yes |
| Offset : +1.000268817 seconds |
| Frequency : \-0.142859 ppm |
| Wander : \-0.010000 ppm per second |
| Last update : 17.8 seconds ago |
| Remaining time : 19988.4 seconds |
| .fi |
| .if n \{\ |
| .RE |
| .\} |
| .sp |
| The fields are explained as follows: |
| .sp |
| \fBActive\fP |
| .RS 4 |
| This shows if the server time smoothing is currently active. Possible values |
| are \fIYes\fP and \fINo\fP. If the \fBleaponly\fP option is included in the \fBsmoothtime\fP |
| directive, \fI(leap second only)\fP will be shown on the line. |
| .RE |
| .sp |
| \fBOffset\fP |
| .RS 4 |
| This is the current offset applied to the time sent to NTP clients. Positive |
| value means the clients are getting time that\(cqs ahead of true time. |
| .RE |
| .sp |
| \fBFrequency\fP |
| .RS 4 |
| The current frequency offset of the served time. Negative value means the |
| time observed by clients is running slower than true time. |
| .RE |
| .sp |
| \fBWander\fP |
| .RS 4 |
| The current frequency wander of the served time. Negative value means the |
| time observed by clients is slowing down. |
| .RE |
| .sp |
| \fBLast update\fP |
| .RS 4 |
| This field shows how long ago the time smoothing process was updated, e.g. |
| \fBchronyd\fP accumulated a new measurement. |
| .RE |
| .sp |
| \fBRemaining time\fP |
| .RS 4 |
| The time it would take for the smoothing process to get to zero offset and |
| frequency if there were no more updates. |
| .RE |
| .RE |
| .sp |
| \fBsmoothtime\fP \fBactivate\fP, \fBsmoothtime\fP \fBreset\fP |
| .RS 4 |
| The \fBsmoothtime\fP command can be used to activate or reset the server time |
| smoothing process if it is configured with the |
| \fBsmoothtime\fP directive. |
| .RE |
| .SS "Monitoring access" |
| .sp |
| \fBcmdaccheck\fP \fIaddress\fP |
| .RS 4 |
| This command is similar to the \fBaccheck\fP command, except that it is |
| used to check whether monitoring access is permitted from a named host. |
| .sp |
| Examples of use are as follows: |
| .sp |
| .if n \{\ |
| .RS 4 |
| .\} |
| .nf |
| cmdaccheck foo.example.net |
| cmdaccheck 1.2.3.4 |
| cmdaccheck 2001:db8::1 |
| .fi |
| .if n \{\ |
| .RE |
| .\} |
| .RE |
| .sp |
| \fBcmdallow\fP [\fBall\fP] [\fIsubnet\fP] |
| .RS 4 |
| This is similar to the \fBallow\fP command, except that it is used to |
| allow particular hosts or subnets to use \fBchronyc\fP to monitor with \fBchronyd\fP on |
| the current host. |
| .RE |
| .sp |
| \fBcmddeny\fP [\fBall\fP] [\fIsubnet\fP] |
| .RS 4 |
| This is similar to the \fBdeny\fP command, except that it is used to allow |
| particular hosts or subnets to use \fBchronyc\fP to monitor \fBchronyd\fP on the |
| current host. |
| .RE |
| .SS "Real\-time clock (RTC)" |
| .sp |
| \fBrtcdata\fP |
| .RS 4 |
| The \fBrtcdata\fP command displays the current RTC parameters. |
| .sp |
| An example output is shown below. |
| .sp |
| .if n \{\ |
| .RS 4 |
| .\} |
| .nf |
| RTC ref time (GMT) : Sat May 30 07:25:56 2015 |
| Number of samples : 10 |
| Number of runs : 5 |
| Sample span period : 549 |
| RTC is fast by : \-1.632736 seconds |
| RTC gains time at : \-107.623 ppm |
| .fi |
| .if n \{\ |
| .RE |
| .\} |
| .sp |
| The fields have the following meaning: |
| .sp |
| \fBRTC ref time (GMT)\fP |
| .RS 4 |
| This is the RTC reading the last time its error was measured. |
| .RE |
| .sp |
| \fBNumber of samples\fP |
| .RS 4 |
| This is the number of previous measurements being used to determine the RTC |
| gain or loss rate. |
| .RE |
| .sp |
| \fBNumber of runs\fP |
| .RS 4 |
| This is the number of runs of residuals of the same sign following the |
| regression fit for (RTC error) versus (RTC time). A value which is small |
| indicates that the measurements are not well approximated by a linear model, |
| and that the algorithm will tend to delete the older measurements to improve |
| the fit. |
| .RE |
| .sp |
| \fBSample span period\fP |
| .RS 4 |
| This is the period that the measurements span (from the oldest to the |
| newest). Without a unit the value is in seconds; suffixes \fIm\fP for minutes, |
| \fIh\fP for hours, \fId\fP for days or \fIy\fP for years can be used. |
| .RE |
| .sp |
| \fBRTC is fast by\fP |
| .RS 4 |
| This is the estimate of how many seconds fast the RTC when it thought |
| the time was at the reference time (above). If this value is large, you |
| might (or might not) want to use the \fBtrimrtc\fP command to bring the |
| RTC into line with the system clock. (Note, a large error will not affect |
| \fBchronyd\fP\(cqs operation, unless it becomes so big as to start causing rounding |
| errors.) |
| .RE |
| .sp |
| \fBRTC gains time at\fP |
| .RS 4 |
| This is the amount of time gained (positive) or lost (negative) by the real |
| time clock for each second that it ticks. It is measured in parts per |
| million. So if the value shown was +1, suppose the RTC was exactly right when |
| it crosses a particular second boundary. Then it would be 1 microsecond fast |
| when it crosses its next second boundary. |
| .RE |
| .RE |
| .sp |
| \fBtrimrtc\fP |
| .RS 4 |
| The \fBtrimrtc\fP command is used to correct the system\(cqs real\-time clock (RTC) to |
| the main system clock. It has no effect if the error between the two clocks is |
| currently estimated at less than a second. |
| .sp |
| The command takes no arguments. It performs the following steps (if the RTC is |
| more than 1 second away from the system clock): |
| .sp |
| .RS 4 |
| .ie n \{\ |
| \h'-04' 1.\h'+01'\c |
| .\} |
| .el \{\ |
| .sp -1 |
| .IP " 1." 4.2 |
| .\} |
| Remember the currently estimated gain or loss rate of the RTC and flush the |
| previous measurements. |
| .RE |
| .sp |
| .RS 4 |
| .ie n \{\ |
| \h'-04' 2.\h'+01'\c |
| .\} |
| .el \{\ |
| .sp -1 |
| .IP " 2." 4.2 |
| .\} |
| Step the real\-time clock to bring it within a second of the system clock. |
| .RE |
| .sp |
| .RS 4 |
| .ie n \{\ |
| \h'-04' 3.\h'+01'\c |
| .\} |
| .el \{\ |
| .sp -1 |
| .IP " 3." 4.2 |
| .\} |
| Make several measurements to accurately determine the new offset between |
| the RTC and the system clock (i.e. the remaining fraction of a second |
| error). |
| .RE |
| .sp |
| .RS 4 |
| .ie n \{\ |
| \h'-04' 4.\h'+01'\c |
| .\} |
| .el \{\ |
| .sp -1 |
| .IP " 4." 4.2 |
| .\} |
| Save the RTC parameters to the RTC file (specified with the |
| \fBrtcfile\fP directive in the configuration file). |
| .RE |
| .RE |
| .sp |
| |
| .RS 4 |
| .sp |
| The last step is done as a precaution against the computer suffering a power |
| failure before either the daemon exits or the \fBwritertc\fP command |
| is issued. |
| .sp |
| \fBchronyd\fP will still work perfectly well both whilst operating and across |
| machine reboots even if the \fBtrimrtc\fP command is never used (and the RTC is |
| allowed to drift away from true time). The \fBtrimrtc\fP command is provided as a |
| method by which it can be corrected, in a manner compatible with \fBchronyd\fP |
| using it to maintain accurate time across machine reboots. |
| .sp |
| The \fBtrimrtc\fP command can be executed automatically by \fBchronyd\fP with the |
| \fBrtcautotrim\fP directive in the configuration |
| file. |
| .RE |
| .sp |
| \fBwritertc\fP |
| .RS 4 |
| The \fBwritertc\fP command writes the currently estimated error and gain or loss rate |
| parameters for the RTC to the RTC file (specified with the |
| \fBrtcfile\fP directive). This information is also |
| written automatically when \fBchronyd\fP is killed (by the SIGHUP, SIGINT, SIGQUIT |
| or SIGTERM signals) or when the \fBtrimrtc\fP command is issued. |
| .RE |
| .SS "Other daemon commands" |
| .sp |
| \fBcyclelogs\fP |
| .RS 4 |
| The \fBcyclelogs\fP command causes all of \fBchronyd\fP\(cqs open log files to be closed |
| and re\-opened. This allows them to be renamed so that they can be periodically |
| purged. An example of how to do this is shown below. |
| .sp |
| .if n \{\ |
| .RS 4 |
| .\} |
| .nf |
| # mv /var/log/chrony/measurements.log /var/log/chrony/measurements1.log |
| # chronyc cyclelogs |
| # ls \-l /var/log/chrony |
| \-rw\-r\-\-r\-\- 1 root root 0 Jun 8 18:17 measurements.log |
| \-rw\-r\-\-r\-\- 1 root root 12345 Jun 8 18:17 measurements1.log |
| # rm \-f measurements1.log |
| .fi |
| .if n \{\ |
| .RE |
| .\} |
| .RE |
| .sp |
| \fBdump\fP |
| .RS 4 |
| The \fBdump\fP command causes \fBchronyd\fP to write its current history of |
| measurements for each of its sources to dump files in the directory specified |
| in the configuration file by the \fBdumpdir\fP |
| directive. Note that \fBchronyd\fP does this automatically when it exits. This |
| command is mainly useful for inspection of the history whilst \fBchronyd\fP is |
| running. |
| .RE |
| .sp |
| \fBrekey\fP |
| .RS 4 |
| The \fBrekey\fP command causes \fBchronyd\fP to re\-read the key file specified in the |
| configuration file by the \fBkeyfile\fP directive. |
| .RE |
| .sp |
| \fBshutdown\fP |
| .RS 4 |
| The \fBshutdown\fP command causes \fBchronyd\fP to exit. This is equivalent to sending |
| the process the SIGTERM signal. |
| .RE |
| .SS "Client commands" |
| .sp |
| \fBdns\fP \fIoption\fP |
| .RS 4 |
| The \fBdns\fP command configures how hostnames and IP addresses are resolved in |
| \fBchronyc\fP. IP addresses can be resolved to hostnames when printing results of |
| \fBsources\fP, \fBsourcestats\fP, \fBtracking\fP |
| and \fBclients\fP commands. Hostnames are resolved in commands that |
| take an address as argument. |
| .sp |
| There are five options: |
| .sp |
| \fBdns \-n\fP |
| .RS 4 |
| Disables resolving IP addresses to hostnames. Raw IP addresses will be |
| displayed. |
| .RE |
| .sp |
| \fBdns +n\fP |
| .RS 4 |
| Enables resolving IP addresses to hostnames. This is the default unless |
| \fBchronyc\fP was started with \fB\-n\fP option. |
| .RE |
| .sp |
| \fBdns \-4\fP |
| .RS 4 |
| Resolves hostnames only to IPv4 addresses. |
| .RE |
| .sp |
| \fBdns \-6\fP |
| .RS 4 |
| Resolves hostnames only to IPv6 addresses. |
| .RE |
| .sp |
| \fBdns \-46\fP |
| .RS 4 |
| Resolves hostnames to both address families. This is the default behaviour |
| unless \fBchronyc\fP was started with the \fB\-4\fP or \fB\-6\fP option. |
| .RE |
| .RE |
| .sp |
| \fBtimeout\fP \fItimeout\fP |
| .RS 4 |
| The \fBtimeout\fP command sets the initial timeout for \fBchronyc\fP requests in |
| milliseconds. If no response is received from \fBchronyd\fP, the timeout is doubled |
| and the request is resent. The maximum number of retries is configured with the |
| \fBretries\fP command. |
| .sp |
| By default, the timeout is 1000 milliseconds. |
| .RE |
| .sp |
| \fBretries\fP \fIretries\fP |
| .RS 4 |
| The \fBretries\fP command sets the maximum number of retries for \fBchronyc\fP requests |
| before giving up. The response timeout is controlled by the |
| \fBtimeout\fP command. |
| .sp |
| The default is 2. |
| .RE |
| .sp |
| \fBkeygen\fP [\fIid\fP [\fItype\fP [\fIbits\fP]]] |
| .RS 4 |
| The \fBkeygen\fP command generates a key that can be added to the |
| key file (specified with the \fBkeyfile\fP directive) |
| to allow NTP authentication between server and client, or peers. The key is |
| generated from the \fI/dev/urandom\fP device and it is printed to standard output. |
| .sp |
| The command has three optional arguments. The first argument is the key number |
| (by default 1), which will be specified with the \fBkey\fP option of the \fBserver\fP |
| or \fBpeer\fP directives in the configuration file. The second argument is the hash |
| function (by default SHA1 or MD5 if SHA1 is not available) and the third |
| argument is the number of bits the key should have, between 80 and 4096 bits |
| (by default 160 bits). |
| .sp |
| An example is: |
| .sp |
| .if n \{\ |
| .RS 4 |
| .\} |
| .nf |
| keygen 73 SHA1 256 |
| .fi |
| .if n \{\ |
| .RE |
| .\} |
| .sp |
| which generates a 256\-bit SHA1 key with number 73. The printed line should |
| then be securely transferred and added to the key files on both server and |
| client, or peers. |
| .RE |
| .sp |
| \fBexit\fP, \fBquit\fP |
| .RS 4 |
| The \fBexit\fP and \fBquit\fP commands exit from \fBchronyc\fP and return the user to the shell. |
| .RE |
| .sp |
| \fBhelp\fP |
| .RS 4 |
| The \fBhelp\fP command displays a summary of the commands and their arguments. |
| .RE |
| .SH "SEE ALSO" |
| .sp |
| \fBchrony.conf(5)\fP, \fBchronyd(8)\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. |