Date: Thu, 13 Apr 2017 00:56:56 +0800 From: Julian Elischer <julian@freebsd.org> To: Colin Percival <cperciva@tarsnap.com>, freebsd-cloud@freebsd.org Subject: Re: amazon/xen... any way at all to pass a message/signal/semaphoere/morse-code to the boot loader? Message-ID: <d0ddea68-13c4-6e6c-9d1c-cbfcd45d9c29@freebsd.org> In-Reply-To: <0100015b61023e1a-decb3a7d-8856-40b0-a2ff-9e8057092254-000000@email.amazonses.com> References: <bf761b5c-63ad-bb14-4a9b-4e1fedced5bd@freebsd.org> <0100015b6070d24d-a23d7d90-11c0-4065-9bd0-0fc71b5874d6-000000@email.amazonses.com> <6f1c694d-1bb7-cdcc-daed-fd2e25dc2a28@freebsd.org> <0100015b61023e1a-decb3a7d-8856-40b0-a2ff-9e8057092254-000000@email.amazonses.com>
next in thread | previous in thread | raw e-mail | index | archive | help
On 12/4/17 3:13 pm, Colin Percival wrote: > On 04/11/17 23:04, 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. > Well, I meant that you'd set this up in advance, so that if it can't boot the > normal partition it would automatically fall back to the recovery partition. > >>> 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??) > Oh, good point. No, the boot loader doesn't know anything about PV drivers, > and there's no emulation, so you can't do anything networky from the boot > loader. > I was thinking of a specialist AMI bootcode that could handle just an xn0 interface. I don't know enough about the xen drivers to know if that would even be possible.
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?d0ddea68-13c4-6e6c-9d1c-cbfcd45d9c29>