From owner-freebsd-cloud@freebsd.org Wed Apr 12 06:34:35 2017 Return-Path: Delivered-To: freebsd-cloud@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id EA1C9D3A613; Wed, 12 Apr 2017 06:34:35 +0000 (UTC) (envelope-from julian@freebsd.org) Received: from vps1.elischer.org (vps1.elischer.org [204.109.63.16]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "vps1.elischer.org", Issuer "CA Cert Signing Authority" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id BC878397; Wed, 12 Apr 2017 06:34:35 +0000 (UTC) (envelope-from julian@freebsd.org) Received: from Julian-MBP3.local (106-68-194-141.dyn.iinet.net.au [106.68.194.141]) (authenticated bits=0) by vps1.elischer.org (8.15.2/8.15.2) with ESMTPSA id v3C6YTLw059955 (version=TLSv1.2 cipher=DHE-RSA-AES128-SHA bits=128 verify=NO); Tue, 11 Apr 2017 23:34:33 -0700 (PDT) (envelope-from julian@freebsd.org) Subject: Re: amazon/xen... any way at all to pass a message/signal/semaphoere/morse-code to the boot loader? To: Toomas Soome References: <0100015b6070d24d-a23d7d90-11c0-4065-9bd0-0fc71b5874d6-000000@email.amazonses.com> <6f1c694d-1bb7-cdcc-daed-fd2e25dc2a28@freebsd.org> <3A0FDF0B-B3CC-4CB7-AF9F-DC7CB60A6B5A@me.com> Cc: freebsd-cloud@freebsd.org, FreeBSD Lists From: Julian Elischer Message-ID: <66834e02-3746-1424-6388-1730d06a1b26@freebsd.org> Date: Wed, 12 Apr 2017 14:34:24 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: <3A0FDF0B-B3CC-4CB7-AF9F-DC7CB60A6B5A@me.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit X-BeenThere: freebsd-cloud@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: "FreeBSD on cloud platforms \(EC2, GCE, Azure, etc.\)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 12 Apr 2017 06:34:36 -0000 On 12/4/17 2:09 pm, Toomas Soome wrote: >> On 12. apr 2017, at 9:04, Julian Elischer wrote: >> >> On 12/4/17 12:34 pm, Colin Percival wrote: >>> [CCing freebsd-cloud, which is the right place for discussions of FreeBSD/EC2] >>> >>> On 04/11/17 21:03, Julian Elischer wrote: >>>> In Amazon ec2 they have no console access (though I heard rumors that it was >>>> available I have not seen any sign of it) so I'd like to put a "recovery >>>> partition" into an AMI. >>>> The trick is how to convince it to boot to that instead of the regular action. >>> Can you get what you want via gptboot's support for selecting the partition >>> to boot via "bootonce" and "bootme" flags? >> not if you can't get onto to the machine. >> When I talk about a recovery partition I mean it in the same way that apple means it.. >> "system won't boot? press the power button and hold down the 'option' key. >> it will give you the option to boot to a recovery mode" >> (* actually I can't remember the keys but you get the idea..) >> >> in our case we would like to be able to recover a customer's AMI by giving a simple set of instructions over the phone. >> We can assume they know how to get into the amazon menus, but we would like to not have to assume much more. >> >>>> The ideal thing would be if there was way to 'influence' one of the smbios >>>> values in some way, and have the boot code see it, but I'm open to any >>>> suggestions. >>>> I really need only 1 bit of information to get through. >>>> >>>> Possibilties include "changing the VM to have only 2G of ram" (we'd never do >>>> that in a real machine). >>>> or maybe temporarily removing all the disks other than the root drive? Almost >>>> anything I could do to signal the boot code to behave differently. >>> I don't think adding/removing disks will be useful, since the extra disks will >>> be Xen blkfront devices; AFAIK the boot loader doesn't know anything about >>> these. (The boot device is also a blkfront device but gets ATA emulation for >>> the benefit of boot loaders.) >>> >>> Maybe you can repurpose some of the logic used for booting over NFS? I've >>> never heard of people booting over NFS when the initial bootstrap comes from >>> disk rather than PXE, but I assume it's possible...? >> Oh I've done it, in the past but you still have the same issue.. >> how do you signal the boot code to do this? >> >> (does an AMI have a bios capable of doing network operations?) I was thinking >> about whether we could add a really simple xn driver into the bootcode to allow >> us to have an console of sorts (accessible from an adjacent machine only??) >> >> >> > > basically you want what zfsbootcfg does but in reverse — with fallback to recovery… yes, that is also a possibility N failed boots in a row.. > > rgds, > toomas > > >