Re: chrony question about -x option
Miroslav Lichvar <[email protected]>
| Newsgroups | gmane.comp.time.chrony.user |
|---|---|
| Message-ID | <Y1ZliR1uIUUKbsRo@localhost> |
On Fri, Oct 21, 2022 at 06:07:19PM +0200, Hubert Verstraete wrote: > Hello > > I want to use chrony on a host "A" connected to the Internet which should > act only as a kind of NTP relay to serve the time from an NTP server on the > Internet to another host "B" on the local network. But I don't want to set > the system clock of host "A" with this Internet time. > To achieve this, I plan to start chrony on host "A" with the option -x. > > The system clock of host "A" is controlled by another process getting the > time from the local network. > Will the Internet time served by host "A" be impacted by the fact that the > system clock is adjusted by the other process ? Yes, it will. How much it depends on the stability of the system clock synchronization. You should make sure it's not synchronized to something synchronizing directly or indirectly to the chronyd -x instance. That would work poorly due to a synchronization loop. > The host "B" needs to synchronize to the raw Internet time in order to keep > the best accuracy. Why does host A not have the same requirement and why does B not send requests directly to Internet? > Regarding the option -x, in chrony 3.5 there was the following note: > It is not recommended to run *chronyd* (with or without *-x*) when another > process is controlling the system clock. > But this note has disappeared since chrony 4.0. > Should I understand that what I want to do is feasible with chrony 4.x but > not with chrony 3.x ? No, nothing changed in this regard. That recommendation just was not very practical. It seems people always have some better or worse reasons to do that and I think it's actually not that different from other supported but suboptimal conditions like running on a VM with an unstable clock. -- Miroslav Lichvar -- To unsubscribe email chrony-users-request-kWFZVVI9zxvPqho9SqqRMmD2FQJk+8+b@public.gmane.org with "unsubscribe" in the subject. For help email chrony-users-request-kWFZVVI9zxvPqho9SqqRMmD2FQJk+8+b@public.gmane.org with "help" in the subject. Trouble? Email [email protected]