From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1N6EBC-0006bK-1C for qemu-devel@nongnu.org; Thu, 05 Nov 2009 21:03:58 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1N6EB8-0006Ty-1a for qemu-devel@nongnu.org; Thu, 05 Nov 2009 21:03:57 -0500 Received: from [199.232.76.173] (port=57595 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1N6EB7-0006Tq-Mi for qemu-devel@nongnu.org; Thu, 05 Nov 2009 21:03:53 -0500 Received: from mail2.shareable.org ([80.68.89.115]:35787) by monty-python.gnu.org with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1N6EB7-0006sC-3A for qemu-devel@nongnu.org; Thu, 05 Nov 2009 21:03:53 -0500 Date: Fri, 6 Nov 2009 02:03:50 +0000 From: Jamie Lokier Subject: Re: [Qemu-devel] [PATCH 0/4] net-bridge: rootless bridge support for qemu Message-ID: <20091106020350.GH21630@shareable.org> References: <1257294485-27015-1-git-send-email-aliguori@us.ibm.com> <20091105041236.GA4981@shareable.org> <20091105082125.GB5774@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20091105082125.GB5774@redhat.com> List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" Cc: Mark McLoughlin , Anthony Liguori , Arnd Bergmann , Dustin Kirkland , Juan Quintela , qemu-devel@nongnu.org Michael S. Tsirkin wrote: > On Thu, Nov 05, 2009 at 04:12:36AM +0000, Jamie Lokier wrote: > > I notice that if we eventually teach the kernel to have unnamed > > bridges (just attach interfaces to each other), only the helper > > commands will need changing to use it :-) > > What do you mean by "attach interfaces to each other"? > Which interfaces do you want to attach to each other? For example, attaching eth0 to tap0 without having to define br0, instead of the current method where you define br0 then attach eth0 and tap0 to it, then transfer eth0's IP configuration to br0, then tell all the network management tools about it. Even Anthony's helper program only makes it easier to do dynamic taps attaching to br0; it won't work on a vanilla Linux system. A vanilla Linux system still needs to be modified to have br0 before the helper can work, and while that modification would be easy for distros to do for most home systems, which run NetworkManager and are limited to exactly one active interface, it's not a pretty change for anything else and cannot be fully automated. (Even on home systems, sometimes you'd want vMs bridged to your mobile phone internet connection, and sometimes you wouldn't. There are still policy issues). Unnamed bridges would simplify the problem on systems which aren't running something like NetworkManager, by keeping eth0's IP configuration on eth0, and Anthony's helper would just attach tap0 to eth0 (or whatever interface you prefer). All you specify is which real network you want the VM's virtual NIC to appear on. It'd behave like VMware etc., but cleaner :-) -- Jamie