Date: Wed, 12 Apr 2017 00:30:00 -0500 From: Leif Pedersen <bilbo@hobbiton.org> To: freebsd-cloud@freebsd.org Cc: Toomas Soome <tsoome@me.com>, Julian Elischer <julian@freebsd.org>, freebsd-xen@freebsd.org Subject: Re: amazon/xen... any way at all to pass a message/signal/semaphoere/morse-code to the boot loader? Message-ID: <CAK-wPOifEdC46G%2Bd5g3BPWqSn87Sr3Fsti5k70X1F=C-=oNGMg@mail.gmail.com> In-Reply-To: <0100015b6070c546-05c6cf24-36e1-487f-be5e-b2bb6efd4472-000000@email.amazonses.com> References: <bf761b5c-63ad-bb14-4a9b-4e1fedced5bd@freebsd.org> <0100015b6070c546-05c6cf24-36e1-487f-be5e-b2bb6efd4472-000000@email.amazonses.com>
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I keep an extra EBS volume handy that has a simple recovery image. If I get stuck into a trouble, I change the normal boot disk to sdb, and attach my recovery volume as sda1. Essentially, the extra volume is my "recovery partition". To make it cheaper, keep only a snapshot of it. Same idea on Google Compute Engine. On Apr 11, 2017 11:34 PM, "Colin Percival" <cperciva@tarsnap.com> 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? > > > 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...? > > -- > Colin Percival > Security Officer Emeritus, FreeBSD | The power to serve > Founder, Tarsnap | www.tarsnap.com | Online backups for the truly paranoid > _______________________________________________ > freebsd-cloud@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-cloud > To unsubscribe, send any mail to "freebsd-cloud-unsubscribe@freebsd.org" >
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