Sorry for my above words, correct like this timex collector is used to monitor sync status between sync system clock from RTC(Real time clock) clock. Can it monitor the sync status between local servers and upstream NTP servers? On Wednesday, February 15, 2023 at 9:53:17 PM UTC+8 Hugo Evelyn wrote:
> Thanks for your reply. According to my researching result, timex collector > is used to sync system clock from RTC(Real time clock) clock. Can it > monitor the sync status between local servers and upstream NTP servers? > > On Wednesday, February 15, 2023 at 4:26:45 PM UTC+8 Ben Kochie wrote: > >> The node_exporter NTP collector is not really useful for what you're >> trying to do. It uses the NTP protocol, which isn't really how you monitor >> the tracking state of an NTP client. I wish I could just remove that >> collector as it's pretty useless and doesn't really do what people think it >> does. >> >> The timex collector is a bit more useful, there is >> node_timex_sync_status. But not all NTP clients update adjtimex the same >> way, so you have to validate it for your environment. >> >> Better, is to actually monitor your NTP client directly. For example, you >> can use the chrony_exporter[0] to monitor chrony NTP tracking status. This >> will give you direct status of how the NTP client is working. >> >> [0]: https://github.com/SuperQ/chrony_exporter >> >> On Wed, Feb 15, 2023 at 9:18 AM Hugo Evelyn <[email protected]> wrote: >> >>> Hi Guys, >>> >>> With reading the info from official website >>> https://github.com/prometheus/node_exporter/blob/master/docs/TIME.md, >>> here comes 2 questions about the metrics. >>> >>> 1. I want to check if my servers are synchronized with NTP server or >>> not. >>> From the source code >>> https://github.com/beevik/ntp/blob/master/ntp.go#L504, for my >>> understanding, node_ntp_offset compares local system clock with NTP server. >>> But from the following definition "ntp.org always sets NTPD time to >>> local clock instead of relaying remote NTP time, so this offset is >>> irrelevant for this NTPD.", I'm a little confuse whether this metrics can >>> be used or not. >>> >>> node_ntp_offset >>> >>> Clock offset >>> <https://en.wikipedia.org/wiki/Network_Time_Protocol#Clock_synchronization_algorithm> >>> between >>> local time and NTPD time. >>> >>> ntp.org always sets NTPD time to local clock instead of relaying remote >>> NTP time, so this offset is irrelevant for this NTPD. >>> >>> This value is used in sanity check as part of causality violation >>> estimate. >>> >>> >>> 2. What the usage of node_ntp_sanity? >>> >>> From the definition >>> >>> node_ntp_sanity >>> >>> Aggregate NTPD health including stratum, leap flag, sane freshness, root >>> distance being less than collector.ntp.max-distance and causality violation >>> being less than collector.ntp.local-offset-tolerance. >>> >>> Causality violation is lower bound estimate of clock error done using >>> SNTP, it's calculated as positive portion of abs(node_ntp_offset) - >>> node_ntp_rtt / 2. >>> >>> From the source code I found this comment in front of the source code of >>> sanity check. So this metrics is to measure which situation? >>> >>> "// Here is SNTP packet sanity check that is exposed to move burden of >>> >>> // configuration from node_exporter user to the developer." >>> >>> From the lines of code >>> https://github.com/prometheus/node_exporter/blob/master/collector/ntp.go#L169, >>> >>> I think node_ntp_sanity is checking resp.Validate(), resp.RootDistance <= >>> *ntpMaxDistance and resp.MinError <= maxerr, if all the 3 conditions are >>> met, then sanity check reponse 1, which means, the current situation is ok. >>> >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "Prometheus Users" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected]. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/prometheus-users/48c393ba-21b7-4378-b1d0-47b7b22caa57n%40googlegroups.com >>> >>> <https://groups.google.com/d/msgid/prometheus-users/48c393ba-21b7-4378-b1d0-47b7b22caa57n%40googlegroups.com?utm_medium=email&utm_source=footer> >>> . >>> >> -- You received this message because you are subscribed to the Google Groups "Prometheus Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/prometheus-users/19697779-0554-4824-8266-360a24c60acdn%40googlegroups.com.
