From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Hurley Subject: Re: netconsole fun Date: Sat, 15 Dec 2012 09:13:58 -0500 Message-ID: <1355580838.2467.39.camel@thor> References: <20121211143004.GA7481@neilslaptop.think-freely.org> <1355239011.2694.24.camel@thor> <20121211164526.GB7481@neilslaptop.think-freely.org> <1355345957.2687.18.camel@thor> <20121213123611.GA12269@hmsreliant.think-freely.org> <1355410171.2605.17.camel@thor> <20121213180815.GA14796@hmsreliant.think-freely.org> <1355426821.2612.16.camel@thor> <20121213211754.GC14796@hmsreliant.think-freely.org> <1355437480.2612.33.camel@thor> <20121214142018.GA24846@shamino.rdu.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: Cong Wang , netdev@vger.kernel.org To: Neil Horman Return-path: Received: from mailout39.mail01.mtsvc.net ([216.70.64.83]:46595 "EHLO n12.mail01.mtsvc.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753193Ab2LOOOI (ORCPT ); Sat, 15 Dec 2012 09:14:08 -0500 In-Reply-To: <20121214142018.GA24846@shamino.rdu.redhat.com> Sender: netdev-owner@vger.kernel.org List-ID: On Fri, 2012-12-14 at 09:20 -0500, Neil Horman wrote: > Ah! I'm sorry, I didn't realize this was really about getting netconsole up > early in the boot, rather than just getting it up robustly using the startup > script. Well, it's both but I should have been clearer here. Sorry about that. > If thats the case, then I would recommend that you modify the initramfs > to do something simmilar to the startup script (since thats where the netconsole > module will get loaded anyway). You can write a script there that will let you > specify the destination ip address and figure out the output dev based on the > routing tables. If you're using dracut to build your initramfs, then this > should be pretty straightforward. When I get some more free time I'll experiment with this approach. Just to clarify something from earlier in the discussion: On Thu, 2012-12-13 at 13:08 -0500, Neil Horman wrote: > On Thu, Dec 13, 2012 at 09:49:31AM -0500, Peter Hurley wrote: .... > > There is an unforeseen consequence of the patch: it breaks device > > renaming because the device will already be in use by netconsole. Which > > is the whole problem with userspace device renaming to begin with... > > > That is bad, but see above, the netconsole service can work around this for you, > allowing you to never have to specify a particular device at all. The breakage is a normal consequence of being able to load netconsole before the udev rules that do device renaming. The same thing would happen modifying initramfs. Basically, once netconsole attaches to a device, that device cannot be renamed. Unfortunately, the default udev behavior messes things up further because it will try to do this: eth0->eth1 eth1->eth0 which means neither device will be renamed. Maybe the net core should just implement persistent device names ;) Thanks again for all your time, Peter Hurley