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1 | 1 | # Monitoring time sync with node_exporter
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2 | 2 |
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| 3 | +## `timex` collector |
| 4 | + |
| 5 | +This collector exports state of kernel time synchronization flag that should be |
| 6 | +maintained by time-keeping daemon and is eventually raised by Linux kernel if |
| 7 | +time-keeping daemon does not update it regularly. |
| 8 | + |
| 9 | +Unfortunately some daemons do not handle this flag properly, e.g. chrony-1.30 |
| 10 | +from Debian/jessie clears `STA_UNSYNC` flag during daemon initialisation and |
| 11 | +does not indicate clock synchronization status using this flag. Modern chrony |
| 12 | +versions should work better. All chrony versions require `rtcsync` option to |
| 13 | +maintain this flag. OpenNTPD does not touch this flag at all till |
| 14 | +OpenNTPD-5.9p1. |
| 15 | + |
| 16 | +On the other hand combination of `sync_status` and `offset` exported by `timex` |
| 17 | +module is the way to monitor if systemd-timesyncd does its job. |
| 18 | + |
3 | 19 | ## `ntp` collector
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4 | 20 |
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5 | 21 | 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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64 | 80 | Causality violation is lower bound estimate of clock error done using SNTP,
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65 | 81 | it's calculated as positive portion of `abs(node_ntp_offset) - node_ntp_rtt / 2`.
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66 | 82 |
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67 |
| -## `timex` collector |
68 |
| - |
69 |
| -This collector exports state of kernel time synchronization flag that should be |
70 |
| -maintained by time-keeping daemon and is eventually raised by Linux kernel if |
71 |
| -time-keeping daemon does not update it regularly. |
72 |
| - |
73 |
| -Unfortunately some daemons do not handle this flag properly, e.g. chrony-1.30 |
74 |
| -from Debian/jessie clears `STA_UNSYNC` flag during daemon initialisation and |
75 |
| -does not indicate clock synchronization status using this flag. Modern chrony |
76 |
| -versions should work better. All chrony versions require `rtcsync` option to |
77 |
| -maintain this flag. OpenNTPD does not touch this flag at all till |
78 |
| -OpenNTPD-5.9p1. |
79 |
| - |
80 |
| -On the other hand combination of `sync_status` and `offset` exported by `timex` |
81 |
| -module is the way to monitor if systemd-timesyncd does its job. |
|
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