Date: Tue, 14 Jul 2015 10:47:59 -0400 From: Paul Mather <paul@gromit.dlib.vt.edu> To: krad <kraduk@gmail.com> Cc: freebsd-stable <freebsd-stable@freebsd.org> Subject: Re: Circular dependency between local_unbound and ntpd? Message-ID: <E6BF2A3D-01CA-4AE5-AB3D-883ADE3DF26C@gromit.dlib.vt.edu> In-Reply-To: <CALfReye4Byhv0dX%2B2JVm=CEuAPnDitYOwgBFm_071Qwg_jvP_g@mail.gmail.com> References: <EDD17B95-0EA7-4C97-836D-7707416C0F07@gromit.dlib.vt.edu> <CALfReye4Byhv0dX%2B2JVm=CEuAPnDitYOwgBFm_071Qwg_jvP_g@mail.gmail.com>
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On Jul 14, 2015, at 10:33 AM, krad <kraduk@gmail.com> wrote: > > As > > $ grep REQUIRE /etc/rc.d/ntpd > # REQUIRE: DAEMON ntpdate FILESYSTEMS devfs > > > You could set something similar to the following in the rc.conf > > ntpdate_hosts="a.b.c.d w.x.y.z" > ntpdate_enable=yes Thanks for that suggestion. I assume the "a.b.c.d w.x.y.z" are IP addresses, not hostnames, otherwise we'd have the same problem. The /etc/rc.d/ntpdate startup script has a "REQUIRE: NETWORKING ..." and /etc/rc.d/local_unbound has a "BEFORE: NETWORKING" in it, meaning it will be running before ntpdate runs. That means DNS resolution will require an accurate clock and, I assume, mean that ntpdate will require IP addresses, too? So, it still comes down to this: do I need to know the IP address of an NTP server to be able to use local_unbound safely with NTP? Cheers, Paul. > > > > > On 14 July 2015 at 14:43, Paul Mather <paul@gromit.dlib.vt.edu <mailto:paul@gromit.dlib.vt.edu>> wrote: > I believe I ran afoul of a circular dependency between local_unbound and ntpd on my 10.2-PRERELEASE system. I use a stock /etc/ntp.conf and use ntpd_sync_on_start="YES". > > Last night, a BIOS settings reset cause my CMOS clock to go WAY out of synch for the first time. No problem, I thought: NTP will correct it at boot. > > Wrong! > > When my system booted, the time was not corrected. Also, DNS resolution was not working. I figured out it was because local_unbound relies on an accurately set clock, but the clock could not be set accurately because my stock ntp.conf requires working DNS resolution to reach the NTP servers. > > That sounds like a potential circular dependency to me. > > My workaround at the time was to look up 0.freebsd.pool.ntp.org <http://0.freebsd.pool.ntp.org/>; on another system; stop ntpd; then do a ntpdate using the IP addresses to set the clock. Once the clock was set accurately, things were all hunky dory. > > Does anyone have any suggestion for an automatic way around this? I guess one way would be to put the IP address of an NTP server into my ntp.conf file, so at least one would be reachable without needing a working DNS? > > My main concern is for those systems like my Raspberry Pi and Beaglebone Black that don't have a battery-backed clock. I currently don't use local_unbound on those, but it seems like I'd encounter this problem routinely if I did. > > Cheers, > > Paul. > _______________________________________________ > freebsd-stable@freebsd.org <mailto:freebsd-stable@freebsd.org> mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-stable <http://lists.freebsd.org/mailman/listinfo/freebsd-stable>; > To unsubscribe, send any mail to "freebsd-stable-unsubscribe@freebsd.org <mailto:freebsd-stable-unsubscribe@freebsd.org>" >
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