From owner-svn-src-head@freebsd.org Fri Nov 24 22:36:25 2017 Return-Path: Delivered-To: svn-src-head@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id CCD31DF32CE for ; Fri, 24 Nov 2017 22:36:25 +0000 (UTC) (envelope-from ian@freebsd.org) Received: from outbound1b.ore.mailhop.org (outbound1b.ore.mailhop.org [54.200.247.200]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id AC92467480 for ; Fri, 24 Nov 2017 22:36:25 +0000 (UTC) (envelope-from ian@freebsd.org) X-MHO-User: ee158be9-d167-11e7-97f4-9d8903e843e3 X-Report-Abuse-To: https://support.duocircle.com/support/solutions/articles/5000540958-duocircle-standard-smtp-abuse-information X-Originating-IP: 73.78.92.27 X-Mail-Handler: DuoCircle Outbound SMTP Received: from ilsoft.org (unknown [73.78.92.27]) by outbound1.ore.mailhop.org (Halon) with ESMTPSA id ee158be9-d167-11e7-97f4-9d8903e843e3; Fri, 24 Nov 2017 22:36:37 +0000 (UTC) Received: from rev (rev [172.22.42.240]) by ilsoft.org (8.15.2/8.15.2) with ESMTP id vAOMaMgK001879; Fri, 24 Nov 2017 15:36:22 -0700 (MST) (envelope-from ian@freebsd.org) Message-ID: <1511562982.1349.8.camel@freebsd.org> Subject: Re: svn commit: r326095 - head/usr.sbin/bsdinstall/scripts From: Ian Lepore To: Warner Losh , "Rodney W. Grimes" Cc: Emmanuel Vadot , Allan Jude , "Conrad E. Meyer" , src-committers , "svn-src-all@freebsd.org" , "svn-src-head@freebsd.org" Date: Fri, 24 Nov 2017 15:36:22 -0700 In-Reply-To: References: <201711242114.vAOLE4b6097164@pdx.rh.CN85.dnsmgr.net> Content-Type: text/plain; charset="ISO-8859-1" X-Mailer: Evolution 3.18.5.1 FreeBSD GNOME Team Port Mime-Version: 1.0 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.25 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 24 Nov 2017 22:36:25 -0000 On Fri, 2017-11-24 at 14:57 -0700, Warner Losh wrote: > On Fri, Nov 24, 2017 at 2:14 PM, Rodney W. Grimes < > freebsd@pdx.rh.cn85.dnsmgr.net> wrote: > > > > > > > > > > > > > > > > We are not talking about removing ntpdate in this thread. > > >   Well, after Ian said that it was deprecated I ask if we should remove > > > it to be honest. > > And I think we have come to the agreement not to do that until the > > official distribution does it as well, is that also correct? > > > I think we should do whatever Ian suggests. I did time things with atomic > clocks and ntpd for about 8 years. He's done them for the same company I > have and knows the current set of quirks better than anybody else in this > thread. These days, it's generally better to use the freebsd ntp pool, like > we have in ntp.conf, and in that scenario, an invocation of ntpd with the > appropriate flags can give you almost identical behavior to ntpdate. The > 'almost' here has a lot of quibbles that aren't relevant to the installer. > And if you don't like the freebsd ntpd pool, then the installer should be > writing an appropriate ntpd.conf file anyway, which has the host. It can > all be done w/o using ntpdate (note: I didn't say remove it), and once > that's in place, and we know there's something not unforeseen, we'll be > ready if the ntpd folks ever make good on their threat to kill ntpdate. So > remove the use of ntpdate here, but keep the utility around. > > tl;dr: Do what ever Ian says, if he doesn't do it himself. He's the expert > with a decade of daily experience making products with ntpd work and > shipping those to customers that have... somewhat diverse environments... > > Warner And yet, even with all that experience, I still neglected to consider the case where ntpd_sync_on_start=YES can cause a time-step on a running system if ntpd is restarted.  (Not that that's a common scenario, but it's still a Bad Thing for people with strict auditing requirements or timing-critical software running.) What the ntpd developers currently say[1] is: The combination of ntpd and sntp now implements the functions of ntpdate. As soon as a few remaining issues with sntp are resolved the ntpdate program will be retired. If you look at what they link to for the "sntp issues"[2] it hasn't been updated since 2011.  So that leads me to the conclusions:  - They have not yet provided a complete path away from ntpdate.  - They don't seem to be in a big hurry to eliminate ntpdate. All in all, I think what Manu committed is Good Enough For Now(tm). [1] https://support.ntp.org/bin/view/Dev/DeprecatingNtpdate [2] https://support.ntp.org/bin/view/Dev/SntpIssues -- Ian