From mboxrd@z Thu Jan 1 00:00:00 1970 From: Constantinos Venetsanopoulos Subject: Re: rbd tool changed format? (breaks compatibility) Date: Mon, 19 Nov 2012 12:20:01 +0200 Message-ID: <50AA07D1.9070402@grnet.gr> References: <50A64F6A.8010505@grnet.gr> <50A6748C.7040303@inktank.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from averel.grnet-hq.admin.grnet.gr ([195.251.29.3]:48839 "EHLO averel.grnet-hq.admin.grnet.gr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753651Ab2KSKUG (ORCPT ); Mon, 19 Nov 2012 05:20:06 -0500 In-Reply-To: <50A6748C.7040303@inktank.com> Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Josh Durgin Cc: ceph-devel@vger.kernel.org, synnefo-devel@googlegroups.com On 11/16/2012 07:14 PM, Josh Durgin wrote: > On 11/16/2012 06:36 AM, Constantinos Venetsanopoulos wrote: >> Hello ceph team, >> >> As you may already know, our team in GRNET is building a complete open >> source cloud platform called Synnefo [1], which already powers our >> production public cloud service ~okeanos [2]. >> >> Synnefo is using Google Ganeti for the low level VM management part [3]. >> As of Jan 2012, we have merged to upstream Ganeti support for VM disks >> on RADOS [4]. >> >> Today we received some feedback, that other people trying to run Ganeti >> with RADOS get an error because probably the output of the 'rbd >> showmapped' command has changed. >> >> I'd like to ask if indeed the output format of the rbd tool has changed. >> More specifically: >> >> 1. Does the 'rbd showmapped' command still returns just the headers if >> no device is mapped? > > No Ack. > > >> 2. Has the separator between the 'rbd showmapped' columns changed >> from \t to ""? > > Yes, this is in the release notes for 0.54 > (http://ceph.com/docs/master/release-notes/#v0-54). > Ack. >> I don't have the latest rbd tool setup (but rather >> ceph-common=0.48.1argonaut-1~bpo60+1), so I can't test it right now, >> but I see this commit: >> >> https://github.com/ceph/ceph/commit/bed55369a96c2651f513b8c9b1a7bb92fb87550a >> > > Yeah, that's the commit that changed it. > >> How stable can we consider rbd tool's output format? >> This is something we want to run in production environment. Using the >> tool rather than the library makes things much simpler. > > Generally it won't change much, but I don't think it should be > considered entirely unchanging. We'll add it to the release notes when > the output does change. We'll probably switch other commands to use > TextTable too, with the same results as with showmapped and lock list. > We could send a message to the mailing list when the output changes as > well, so you can prepare for a future release. That would be great, and highly appreciated. Please drop us an email at the following mailing lists, when the rbd tool's format changes: synnefo-devel@googlegroups.com ganeti-devel@googlegroups.com > > Perhaps we should add a --format json|plain option so you don't have to > rely on particular formatting, you just parse the json. This would > match existing usage by many 'ceph ...' commands, and be easier > for scripts to use in general. That would be even better! That would be the best approach for us, since we use it inside python code. Parsing a json is very simple and we will be able to maintain compatibility even when the format changes. Thanks, Consantinos