On 10.04.2014 14:00, [email protected] digested: > From: Terje Mathisen <[email protected]> > > Rob wrote: >> > OF COURSE ntpd should simply listen for SIGHUP and when it is received >> > re-read the config file. Like almost all Unix daemons do. > > Here's the crux of the matter: > ntpd is _not_ a "Unix daemon", or at least not just that: The same code > runs on many different operating systems, some of which don't implement > SIGHUP at all, or at least not in a compatible manner.
Now this sounds dangerously close to "ntpd cannot possibly use a config file, because it is supposed to be running on various OSes with incompatible character and end-of-line encodings" ... > From: Harlan Stenn <[email protected]> > > Amongst the many reasons why we did not let SIGHUP restart the daemon > was that back in the old days we used modem drivers a lot more often. > The HUP signal was generic - it was not really associated with any > specific device. I wouldn't be surprised if spurious SIGHUPs were still occuring (and possibly reaching unrelated daemon processes) today - just think of how many DSL routers happen to have a unixoid OS and are actually running a pppd (whose manpage mentions HUPs a lot). Point is, for daemons *other* than ntpd, "rereading the config" that nobody did edit will likely have no noticeable effect at all. For ntpd, with the round robin DNS pools yielding different servers every time you resolve, and possibly losing status even for those servers that did *not* change ... things might look different. Then again, it's not like there are no established unixoid methods *other* than HUP - from USR1 (no example whose name I'd remember off the top of my head) to polling the config file's stat() periodically (a la /etc/crontab) to a simple CLI via local special files (a la Nagios command pipe, or even "echo 1 > /proc/sys/foo/bar") to opaque IPC hidden behind a dedicated util's command line options (a la apachectl, or fetchmail --quit). At the end of the day, lots of people - and the most important clustering solutions - won't care to look past the OS' meta-command, be it "service mumblefoo reload" or "svcadm restart mumblefoo", as long as that *works*. :-} Regards, J. Bern -- *NEU* - NEC IT-Infrastruktur-Produkte im <http://www.linworks-shop.de/>: Server--Storage--Virtualisierung--Management SW--Passion for Performance Jochen Bern, Systemingenieur --- LINworks GmbH <http://www.LINworks.de/> Postfach 100121, 64201 Darmstadt | Robert-Koch-Str. 9, 64331 Weiterstadt PGP (1024D/4096g) FP = D18B 41B1 16C0 11BA 7F8C DCF7 E1D5 FAF4 444E 1C27 Tel. +49 6151 9067-231, Zentr. -0, Fax -299 - Amtsg. Darmstadt HRB 85202 Unternehmenssitz Weiterstadt, Geschäftsführer Metin Dogan, Oliver Michel _______________________________________________ questions mailing list [email protected] http://lists.ntp.org/listinfo/questions
