105 lines
5.1 KiB
Markdown
105 lines
5.1 KiB
Markdown
# chrony Input Plugin
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Get standard chrony metrics, requires chronyc executable.
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Below is the documentation of the various headers returned by `chronyc
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tracking`.
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- Reference ID - This is the refid and name (or IP address) if available, of the
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server to which the computer is currently synchronised. If this is 127.127.1.1
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it means the computer is not synchronised to any external source and that you
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have the ‘local’ mode operating (via the local command in chronyc (see section
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local), or the local directive in the ‘/etc/chrony.conf’ file (see section
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local)).
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- Stratum - The stratum indicates how many hops away from a computer with an
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attached reference clock we are. Such a computer is a stratum-1 computer, so
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the computer in the example is two hops away (i.e. a.b.c is a stratum-2 and is
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synchronised from a stratum-1).
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- Ref time - This is the time (UTC) at which the last measurement from the
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reference source was processed.
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- System time - In normal operation, chronyd never steps the system clock,
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because any jump in the timescale can have adverse consequences for certain
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application programs. Instead, any error in the system clock is corrected by
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slightly speeding up or slowing down the system clock until the error has been
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removed, and then returning to the system clock’s normal speed. A consequence
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of this is that there will be a period when the system clock (as read by other
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programs using the gettimeofday() system call, or by the date command in the
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shell) will be different from chronyd's estimate of the current true time
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(which it reports to NTP clients when it is operating in server mode). The
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value reported on this line is the difference due to this effect.
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- Last offset - This is the estimated local offset on the last clock update.
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- RMS offset - This is a long-term average of the offset value.
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- Frequency - The ‘frequency’ is the rate by which the system’s clock would be
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wrong if chronyd was not correcting it. It is expressed in ppm (parts per
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million). For example, a value of 1ppm would mean that when the system’s
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clock thinks it has advanced 1 second, it has actually advanced by 1.000001
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seconds relative to true time.
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- Residual freq - This shows the ‘residual frequency’ for the currently selected
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reference source. This reflects any difference between what the measurements
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from the reference source indicate the frequency should be and the frequency
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currently being used. The reason this is not always zero is that a smoothing
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procedure is applied to the frequency. Each time a measurement from the
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reference source is obtained and a new residual frequency computed, the
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estimated accuracy of this residual is compared with the estimated accuracy
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(see ‘skew’ next) of the existing frequency value. A weighted average is
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computed for the new frequency, with weights depending on these accuracies. If
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the measurements from the reference source follow a consistent trend, the
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residual will be driven to zero over time.
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- Skew - This is the estimated error bound on the frequency.
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- Root delay - This is the total of the network path delays to the stratum-1
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computer from which the computer is ultimately synchronised. In certain
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extreme situations, this value can be negative. (This can arise in a symmetric
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peer arrangement where the computers’ frequencies are not tracking each other
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and the network delay is very short relative to the turn-around time at each
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computer.)
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- Root dispersion - This is the total dispersion accumulated through all the
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computers back to the stratum-1 computer from which the computer is ultimately
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synchronised. Dispersion is due to system clock resolution, statistical
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measurement variations etc.
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- Leap status - This is the leap status, which can be Normal, Insert second,
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Delete second or Not synchronised.
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## Global configuration options <!-- @/docs/includes/plugin_config.md -->
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In addition to the plugin-specific configuration settings, plugins support
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additional global and plugin configuration settings. These settings are used to
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modify metrics, tags, and field or create aliases and configure ordering, etc.
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See the [CONFIGURATION.md][CONFIGURATION.md] for more details.
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[CONFIGURATION.md]: ../../../docs/CONFIGURATION.md#plugins
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## Configuration
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```toml @sample.conf
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# Get standard chrony metrics, requires chronyc executable.
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[[inputs.chrony]]
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## If true, chronyc tries to perform a DNS lookup for the time server.
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# dns_lookup = false
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```
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## Metrics
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- chrony
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- system_time (float, seconds)
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- last_offset (float, seconds)
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- rms_offset (float, seconds)
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- frequency (float, ppm)
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- residual_freq (float, ppm)
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- skew (float, ppm)
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- root_delay (float, seconds)
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- root_dispersion (float, seconds)
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- update_interval (float, seconds)
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### Tags
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- All measurements have the following tags:
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- reference_id
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- stratum
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- leap_status
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## Example Output
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```text
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chrony,leap_status=normal,reference_id=192.168.1.1,stratum=3 frequency=-35.657,system_time=0.000027073,last_offset=-0.000013616,residual_freq=-0,rms_offset=0.000027073,root_delay=0.000644,root_dispersion=0.003444,skew=0.001,update_interval=1031.2 1463750789687639161
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```
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