From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jeremy Fitzhardinge <jeremy@goop.org>
Subject: Re: [PATCH]: xl: use libuuid to generate random UUID's
Date: Tue, 10 Aug 2010 12:38:09 -0700
Message-ID: <4C61AAA1.5000600@goop.org>
References: <1280944162.18490.219.camel@qabil.uk.xensource.com>	<4FA716B1526C7C4DB0375C6DADBC4EA37AD0596B2F@LONPMAILBOX01.citrite.net>	<4C5A21A3.3020601@goop.org>
	<1281437086.24292.3882.camel@zakaz.uk.xensource.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Return-path: <xen-devel-bounces@lists.xensource.com>
In-Reply-To: <1281437086.24292.3882.camel@zakaz.uk.xensource.com>
List-Unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
List-Post: <mailto:xen-devel@lists.xensource.com>
List-Help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-Subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
Sender: xen-devel-bounces@lists.xensource.com
Errors-To: xen-devel-bounces@lists.xensource.com
To: Ian Campbell <Ian.Campbell@citrix.com>
Cc: Ian Pratt <Ian.Pratt@eu.citrix.com>, Xen Devel <xen-devel@lists.xensource.com>, Ian Jackson <Ian.Jackson@eu.citrix.com>, "Gianni Tedesco (3P)" <gianni.tedesco@citrix.com>, Stefano Stabellini <Stefano.Stabellini@eu.citrix.com>
List-Id: xen-devel@lists.xenproject.org

  On 08/10/2010 03:44 AM, Ian Campbell wrote:
> On Thu, 2010-08-05 at 03:27 +0100, Jeremy Fitzhardinge wrote:
>> On 08/04/2010 07:19 PM, Ian Pratt wrote:
>>> The best approach is to generate locally administered MAC addresses
>> hence giving us 46 bits of freedom rather than XenSource registered
>> OUI addresses which have just 24 bits -- collisions will be *much*
>> less likely. Further, it's best not to generate random addresses every
>> time, but to derive the MAC address from a good hash of the VM UUID
>> and the NIC number so that they are deterministic.
>>
>> Yes!  I've been doing that manually (where my hash is '+'), but its
>> irritating to keep doing over and over.
> Where I care about a stable MAC I use
> 	vif = [ 'mac=xx:xx:xx:xx:xx:xx' ]
> in my domain config file. AFAICT that is the only 100% reliable way to
> get a stable MAC address since the other schemes all have some corner
> case or other...

I always manually set a uuid in the domain (well, uuid-gen), and I'd 
like the mac to be derived from that.

     J