From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mats Petersson Subject: Re: Many same managed domain Date: Sun, 22 Jul 2007 23:20:54 +0100 Message-ID: <46a3d86b.2015300a.555f.38d1@mx.google.com> References: <91C7CC1E6AF558kanno.masaki@jp.fujitsu.com> <20070722144609.GA22043@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; format=flowed Return-path: In-Reply-To: <20070722144609.GA22043@redhat.com> References: <91C7CC1E6AF558kanno.masaki@jp.fujitsu.com> <20070722144609.GA22043@redhat.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: "Daniel P. Berrange" , Masaki Kanno Cc: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org At 15:46 22/07/2007, Daniel P. Berrange wrote: >On Sun, Jul 22, 2007 at 02:09:01PM +0900, Masaki Kanno wrote: > > Hi, > > > > When I tested xm new command without uuid parameter repeatedly, > > I saw many same managed domain as follows. > > > > # xm list > > Name ID Mem > VCPUs State Time(s) > > > Domain-0 0 941 2 r----- 51.9 > > # xm new /xen/vm1.conf > > Using config file "/xen/vm1.conf". > > # xm new /xen/vm1.conf > > Using config file "/xen/vm1.conf". > > # xm new /xen/vm1.conf > > Using config file "/xen/vm1.conf". > > # xm list > > Name ID Mem > VCPUs State Time(s) > > > Domain-0 0 941 2 r----- 56.3 > > > vm1 256 1 0.0 > > > vm1 256 1 0.0 > > > vm1 256 1 0.0 > > > > > > But, when I tested xm new command with uuid parameter repeatedly, > > I did not see same managed domain as follows. > > > > # xm list > > Name ID Mem > VCPUs State Time(s) > > > Domain-0 0 941 2 r----- 69.9 > > # xm new /xen/vm1.conf uuid="aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee" > > Using config file "/xen/vm1.conf". > > # xm new /xen/vm1.conf uuid="aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee" > > Using config file "/xen/vm1.conf". > > # xm new /xen/vm1.conf uuid="aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee" > > Using config file "/xen/vm1.conf". > > # xm list > > Name ID Mem > VCPUs State Time(s) > > > Domain-0 0 941 2 r----- 74.4 > > > vm1 256 1 0.0 > > > > > > I think that xm new command should cause a command error if without > > uuid parameter. What do you think? > >No that would break backwards compatability for user who rely on Xen >autogenerating the UUID. > >In order to maintain back-compatability with existing use cases, the user >needs to be able to update the existing VM config with 'xm new' if the name >or UUID match, while preventing multiple VMs with same name. So the the rules >when defining a new VM need to follow this logic > > - If the UUID is not specified > - If a VM with same name exists > => Update the config for that existing VM > - Else no vm with same name exists > => Define a brand new VM with auto-generated UUID > - Else UUID is specified > - If a VM with same UUID exists > - If name is different > => Error > - Else if name is same > => Update the config for that existing VM > - Else no VM with same UUID exists > => Define a branch new VM with that name > >Depending on where in the XenD code you put this error checking you may need >some extra special case rules handle stuff like localhost migration. With live migration/save&restore, you shouldn't need to worry about the name [1], but obviously, the UUID should be the same for the new and old migrated domain, and live migration should be allowed to "localhost". [1] Part of "xm save/migrate" is to prepend "migrating" to the name of the domain, so there should be no name conflict with live migration when the new domain is created. -- Mats >Regards, >Dan. >-- >|=- Red Hat, Engineering, Emerging Technologies, Boston. +1 978 392 2496 -=| >|=- Perl modules: http://search.cpan.org/~danberr/ -=| >|=- Projects: http://freshmeat.net/~danielpb/ -=| >|=- GnuPG: 7D3B9505 F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 -=| > >_______________________________________________ >Xen-devel mailing list >Xen-devel@lists.xensource.com >http://lists.xensource.com/xen-devel