From: Isaac Beckett <isaactbeckett@gmail.com>
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Subject: Re: A "diskless" Xen dom0 entirely in the ESP
In-Reply-To: <8f1653ba-e803-4b1d-9403-4284e647c3df@pobox.com>
Cc: rptb1+alpine@pobox.com
Date: Mon, 11 Nov 2024 13:33:43 -0500
Message-Id: <2B1BA8D8-09B8-4727-A075-2D885B55E97F@gmail.com>
References: <8f1653ba-e803-4b1d-9403-4284e647c3df@pobox.com>
To: ~alpine/users@lists.alpinelinux.org

> On Nov 10, 2024, at 8:39 AM, rptb1+alpine@pobox.com wrote:
>=20
> =EF=BB=BFHello.
>=20
> I'm hoping for a bit of advice on how to proceed.
>=20
> I'm interested in creating an Alpine Xen dom0 that runs entirely from the E=
SP partition (a.k.a. the EFI partition).  I believe this should be possible b=
y combining a clean "diskless" installation with apkovl to provide configura=
tion.  It doesn't really matter about the bootloader -- I can make Grub or x=
en.efi or EFISTUB work.  I'm wondering about the best way to achieve my goal=
.
>=20
> It seems to me that I should be able to install the entire "diskless" Alpi=
ne in the initramfs.
>=20
> The instructions at https://wiki.alpinelinux.org/wiki/Create_a_Bootable_De=
vice seem to get *quite* close to what I want, but of course they are creati=
ng a bootable MBR partition, not an initramfs.
>=20
> The boot sequence would be:
>=20
> 1. UEFI bios
> 2. bootloader (optional)
> 3. xen.efi
> 4. kernel
> 5. initramfs
> 6. init script
> 7. apkovl etc.
>=20
> It seems to me that I might need to make a custom initramfs init script th=
at *does not* pivot to another root filesystem, since the initramfs will *be=
* the diskless filesystem.
>=20
> I'm writing to the mailing list to see if anyone else has achieved a simil=
ar result, even if in a different way.  Or if anyone has a different suggest=
ion for how I might achieve my result.  Or any short cuts for this work.
>=20
> It would be nice if the final system is able to upgrade itself without a l=
ot of work, too.
>=20
> The initramfs init script seems quite flexible, but I haven't found a way t=
o convince it that it's living in a finished diskless installation.
>=20
> Thanks!


Okay, I=E2=80=99ve seen other folks discuss *how* you could accomplish this (=
One File Linux looks especially interesting)

But I=E2=80=99m curious as to *why* you want to do this. And why as a Xen do=
m0 specifically?=