Re: [netmod] Datastore leaf for yang instance data

Juergen Schoenwaelder <j.schoenwaelder@jacobs-university.de> Wed, 28 November 2018 10:20 UTC

Return-Path: <j.schoenwaelder@jacobs-university.de>
X-Original-To: netmod@ietfa.amsl.com
Delivered-To: netmod@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 0147C130EBE for <netmod@ietfa.amsl.com>; Wed, 28 Nov 2018 02:20:56 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.899
X-Spam-Level:
X-Spam-Status: No, score=-1.899 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, RCVD_IN_DNSWL_NONE=-0.0001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id je_zuH6pd_yd for <netmod@ietfa.amsl.com>; Wed, 28 Nov 2018 02:20:54 -0800 (PST)
Received: from atlas5.jacobs-university.de (atlas5.jacobs-university.de [212.201.44.20]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 3C8EE130E4F for <netmod@ietf.org>; Wed, 28 Nov 2018 02:20:54 -0800 (PST)
Received: from localhost (demetrius5.irc-it.jacobs-university.de [10.70.0.222]) by atlas5.jacobs-university.de (Postfix) with ESMTP id BE88AEC0; Wed, 28 Nov 2018 11:20:52 +0100 (CET)
X-Virus-Scanned: amavisd-new at jacobs-university.de
Received: from atlas5.jacobs-university.de ([10.70.0.217]) by localhost (demetrius5.jacobs-university.de [10.70.0.222]) (amavisd-new, port 10032) with ESMTP id gkE3XaSE-KjO; Wed, 28 Nov 2018 11:20:52 +0100 (CET)
Received: from hermes.jacobs-university.de (hermes.jacobs-university.de [212.201.44.23]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "hermes.jacobs-university.de", Issuer "Jacobs University CA - G01" (verified OK)) by atlas5.jacobs-university.de (Postfix) with ESMTPS; Wed, 28 Nov 2018 11:20:52 +0100 (CET)
Received: from localhost (demetrius3.jacobs-university.de [212.201.44.48]) by hermes.jacobs-university.de (Postfix) with ESMTP id A7B6C2003F; Wed, 28 Nov 2018 11:20:52 +0100 (CET)
X-Virus-Scanned: amavisd-new at jacobs-university.de
Received: from hermes.jacobs-university.de ([212.201.44.23]) by localhost (demetrius3.jacobs-university.de [212.201.44.32]) (amavisd-new, port 10024) with ESMTP id V_iW_pO-imzU; Wed, 28 Nov 2018 11:20:52 +0100 (CET)
Received: from exchange.jacobs-university.de (SXCHMB01.jacobs.jacobs-university.de [10.70.0.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "exchange.jacobs-university.de", Issuer "DFN-Verein Global Issuing CA" (verified OK)) by hermes.jacobs-university.de (Postfix) with ESMTPS id 00EDD20037; Wed, 28 Nov 2018 11:20:51 +0100 (CET)
Received: from anna.localdomain (10.50.218.117) by sxchmb03.jacobs.jacobs-university.de (10.70.0.155) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.1591.10; Wed, 28 Nov 2018 11:20:51 +0100
Received: by anna.localdomain (Postfix, from userid 501) id 3DEB330045766D; Wed, 28 Nov 2018 11:20:51 +0100 (CET)
Date: Wed, 28 Nov 2018 11:20:50 +0100
From: Juergen Schoenwaelder <j.schoenwaelder@jacobs-university.de>
To: =?utf-8?Q?Bal=C3=A1zs?= Lengyel <balazs.lengyel@ericsson.com>
CC: Ladislav Lhotka <lhotka@nic.cz>, Martin Bjorklund <mbj@tail-f.com>, "netmod@ietf.org" <netmod@ietf.org>
Message-ID: <20181128102050.37iyrx2xhdohnepb@anna.jacobs.jacobs-university.de>
Reply-To: Juergen Schoenwaelder <j.schoenwaelder@jacobs-university.de>
Mail-Followup-To: =?utf-8?Q?Bal=C3=A1zs?= Lengyel <balazs.lengyel@ericsson.com>, Ladislav Lhotka <lhotka@nic.cz>, Martin Bjorklund <mbj@tail-f.com>, "netmod@ietf.org" <netmod@ietf.org>
References: <87y3a6izap.fsf@nic.cz> <20181106063648.jjf2scqzoack5l3z@anna.jacobs.jacobs-university.de> <58740c15bf3277e04329546476f60c1d12516594.camel@nic.cz> <20181106.104157.239419955739949818.mbj@tail-f.com> <866ff105cf8fda7eadbdce5b344f4cd734fd99b8.camel@nic.cz> <1f4103c1-4953-3df4-d50d-aed1961fbc50@ericsson.com> <20181123154951.anviss5nllq6gwrn@anna.jacobs.jacobs-university.de> <d1716b42-12d0-072a-76b7-74b9a8efcbe9@ericsson.com>
MIME-Version: 1.0
Content-Type: text/plain; charset="iso-8859-1"
Content-Disposition: inline
X-Clacks-Overhead: GNU Terry Pratchett
Content-Transfer-Encoding: 8bit
In-Reply-To: <d1716b42-12d0-072a-76b7-74b9a8efcbe9@ericsson.com>
User-Agent: NeoMutt/20180716
X-ClientProxiedBy: SXCHMB04.jacobs.jacobs-university.de (10.70.0.156) To sxchmb03.jacobs.jacobs-university.de (10.70.0.155)
Archived-At: <https://mailarchive.ietf.org/arch/msg/netmod/6WdwT2P70-6RNUH9iMCdTfkAQCU>
Subject: Re: [netmod] Datastore leaf for yang instance data
X-BeenThere: netmod@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: NETMOD WG list <netmod.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/netmod>, <mailto:netmod-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/netmod/>
List-Post: <mailto:netmod@ietf.org>
List-Help: <mailto:netmod-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/netmod>, <mailto:netmod-request@ietf.org?subject=subscribe>
X-List-Received-Date: Wed, 28 Nov 2018 10:20:56 -0000

On Wed, Nov 28, 2018 at 09:41:12AM +0000, Balázs Lengyel wrote:
> 
> > I do not buy this story. Your software needs to decide somehow what
> > instance data means. A config true leaf in candidate means something
> > different than the same config true leaf in running and this yet again
> > means something different than the same config true leaf in operational.
> > 
> > /js
> 
> BALAZS: As I understood the WG decided that this draft should only be about
> the format of the yang instance data. What the SW does with it is out of
> scope. So considerations whether instance data should be loaded into running
> or candidate or not at all, are outside the scope.

If you do not know what the instance data means, any attempt to use it
is kind of broken.
 
> I want to provide a datastore indicator, but how that should be used (and
> thus what is exactly means) is out of scope.

I disagree. The datastore indicator is needed to understand what the
data means, i.e., to do anything meaningful with it.

> Anyway in some cases it would be problematic to define a single datastore
> parameter. E.g. the draft allows the real world use case of putting config
> and state data in the same file. In this case state data is associated with
> operational while config data is with running/candidate. In the non-NMDA
> case I do not even know what the correct daatastore is for state data.

We created NMDA because mixing <running> with <operational> is broken
in a number of cases. I am fine to accept that the datastore indicator
may be absent paired with a clear warning that in this case it is
undefined what the data means. (And I will hope that robust
implementations will avoid working with data that has unclear
semantics or at least generate warnings.)

/js

-- 
Juergen Schoenwaelder           Jacobs University Bremen gGmbH
Phone: +49 421 200 3587         Campus Ring 1 | 28759 Bremen | Germany
Fax:   +49 421 200 3103         <https://www.jacobs-university.de/>