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@ -1,5 +1,21 @@ |
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# Monitoring time sync with node_exporter |
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## `timex` collector |
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This collector exports state of kernel time synchronization flag that should be |
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maintained by time-keeping daemon and is eventually raised by Linux kernel if |
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time-keeping daemon does not update it regularly. |
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Unfortunately some daemons do not handle this flag properly, e.g. chrony-1.30 |
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from Debian/jessie clears `STA_UNSYNC` flag during daemon initialisation and |
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does not indicate clock synchronization status using this flag. Modern chrony |
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versions should work better. All chrony versions require `rtcsync` option to |
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maintain this flag. OpenNTPD does not touch this flag at all till |
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OpenNTPD-5.9p1. |
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On the other hand combination of `sync_status` and `offset` exported by `timex` |
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module is the way to monitor if systemd-timesyncd does its job. |
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## `ntp` collector |
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NOTE: This collector is deprecated and will be removed in the next major version release. |
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@ -64,18 +80,3 @@ being less than `collector.ntp.local-offset-tolerance`. |
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Causality violation is lower bound estimate of clock error done using SNTP, |
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it's calculated as positive portion of `abs(node_ntp_offset) - node_ntp_rtt / 2`. |
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## `timex` collector |
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This collector exports state of kernel time synchronization flag that should be |
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maintained by time-keeping daemon and is eventually raised by Linux kernel if |
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time-keeping daemon does not update it regularly. |
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Unfortunately some daemons do not handle this flag properly, e.g. chrony-1.30 |
|
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|
|
from Debian/jessie clears `STA_UNSYNC` flag during daemon initialisation and |
|
|
|
|
does not indicate clock synchronization status using this flag. Modern chrony |
|
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|
|
versions should work better. All chrony versions require `rtcsync` option to |
|
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|
|
maintain this flag. OpenNTPD does not touch this flag at all till |
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|
OpenNTPD-5.9p1. |
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|
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On the other hand combination of `sync_status` and `offset` exported by `timex` |
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module is the way to monitor if systemd-timesyncd does its job. |
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