From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44112) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VW4kf-0002pC-SJ for qemu-devel@nongnu.org; Tue, 15 Oct 2013 09:33:42 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VW4kW-00066L-O7 for qemu-devel@nongnu.org; Tue, 15 Oct 2013 09:33:33 -0400 Received: from e23smtp01.au.ibm.com ([202.81.31.143]:34163) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VW4kW-00065t-4V for qemu-devel@nongnu.org; Tue, 15 Oct 2013 09:33:24 -0400 Received: from /spool/local by e23smtp01.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 15 Oct 2013 23:33:15 +1000 Received: from d23relay03.au.ibm.com (d23relay03.au.ibm.com [9.190.235.21]) by d23dlp03.au.ibm.com (Postfix) with ESMTP id BD5A33578052 for ; Wed, 16 Oct 2013 00:33:12 +1100 (EST) Received: from d23av02.au.ibm.com (d23av02.au.ibm.com [9.190.235.138]) by d23relay03.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r9FDWvnV4522306 for ; Wed, 16 Oct 2013 00:33:01 +1100 Received: from d23av02.au.ibm.com (localhost [127.0.0.1]) by d23av02.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id r9FDX8qt026279 for ; Wed, 16 Oct 2013 00:33:08 +1100 Message-ID: <525D4412.2000702@linux.vnet.ibm.com> Date: Tue, 15 Oct 2013 21:33:06 +0800 From: mike MIME-Version: 1.0 References: <1381810677-4369-1-git-send-email-qiudayu@linux.vnet.ibm.com> <525CCD98.7010707@weilnetz.de> <525D36B1.3050208@redhat.com> In-Reply-To: <525D36B1.3050208@redhat.com> Content-Type: multipart/alternative; boundary="------------010308070106040108020301" Subject: Re: [Qemu-devel] [PATCH v2] net/net: Change the default mac address of nic List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Eric Blake Cc: Stefan Weil , qemu-devel@nongnu.org, stefanha@redhat.com, aliguori@amazon.com This is a multi-part message in MIME format. --------------010308070106040108020301 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 10/15/2013 08:36 PM, Eric Blake wrote: > On 10/14/2013 11:07 PM, Stefan Weil wrote: >> Is it reasonable to get a random mac address in your guest? I don't >> think so. It would no longer be possible to connect to a guest using >> ssh, restart that guest and connect again with ssh. > Agreed - libvirt ALWAYS passes a MAC to qemu, even if the user did not > specify a MAC to libvirt, precisely because the MAC must be reproducible > rather than random to avoid changing the guest ABI. I don't think this > patch is needed - it's up to management to use qemu correctly. Yes, you are right in this condition. But qemu support Mac address unset. Also we can get the ip address through a lot of different ways, like use monitor to get the mac and then get the ip. So we can login use ssh. But as you mentioned, this patch is not needed, I don't agree with you. First, this patch just fix the Potential issue of this feature. Now libvirt maybe can't triggered this issue, who can promise in future will not. The second is, qemu not only be used by libvirt, lots of developers like to use the command line to boot up the guest. And in the future, we are not sure about other program will use qemu. The third is, when one feature has a issue in qemu, no matter when it is been triggered, should we not fix it? Mike Thanks --------------010308070106040108020301 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 8bit
On 10/15/2013 08:36 PM, Eric Blake wrote:
On 10/14/2013 11:07 PM, Stefan Weil wrote:

Is it reasonable to get a random mac address in your guest? I don't
think so. It would no longer be possible to connect to a guest using
ssh, restart that guest and connect again with ssh.

Agreed - libvirt ALWAYS passes a MAC to qemu, even if the user did not
specify a MAC to libvirt, precisely because the MAC must be reproducible
rather than random to avoid changing the guest ABI.  I don't think this
patch is needed - it's up to management to use qemu correctly.
Yes, you are right in this condition. But qemu support Mac address unset.
Also we can get the ip address through a lot of different ways, like use
monitor to get the mac and then get the ip. So we can login use ssh.

But as you mentioned, this patch is not needed, I don't agree with you.

First, this patch just fix the Potential issue of this feature. Now libvirt
maybe can't triggered this issue, who can promise in future will not.

The second is,  qemu not only be used by libvirt,  lots of developers like
to use the command line to boot up the guest. And in the future, we
are not sure about other program will use qemu. 

The third is, when one feature has a issue in qemu,
no matter when it is been triggered, should we not fix it?

Mike
Thanks

    

    

  


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