F35 Change: Build Fedora Cloud Images with Hybrid BIOS+UEFI Boot Support (System-Wide Change)

[Ben Cotton]

https://fedoraproject.org/wiki/Changes/FedoraCloudHybridBoot

== Summary ==

With recent changes in public cloud widely accepting the
use of UEFI boot, it would be consistent to add hybrid boot in support of
both unifying the legacy (BIOS) and UEFI boot to the Fedora Linux
cloud base images.

== Owner ==

* Name: [[User:Davdunc|David Duncan]], [[User:Chrismurphy|Chris
Murphy]], [[User:Salimma|Michel Alexandre Salim]],
[[User:Dcavalca|Davide Cavalca]], [[User:Ngompa|Neal Gompa]],
[[User:Dustymabe|Dusty Mabe]]
* Email: davdunc(a)amazon.com, chrismurphy(a)fedoraproject.org,
michel(a)michel-slm.name, dcavalca(a)fb.com, ngompa13(a)gmail.com,
dusty(a)dustymabe.com
* Products: Fedora Cloud Edition
* Responsible WGs: Fedora Cloud WG


== Detailed Description ==
The Fedora Cloud Edition image will be updated to be configured with
multiple partitions and a GPT label instead of one single partition
and implicit MBR.

The partition order will be:

# A BIOS boot partition
# An EFI System partition
# A general data partition


== Benefit to Fedora ==

This is a continuation from the changes outlined in the
[[Releases/34|Fedora Linux 34]] changes to
[[Changes/UnifyGrubConfig|unify the Grub configuration files]]. There
has been an overwhelming support in the public cloud architectures
leading to widespread support for UEFI boot in support of migration
work. This also adds support for other anticipated changes that would
require this modification to include the boot partitions; both legacy
boot as a fallback through the BIOS boot partition and UEFI boot
through the EFI system partition. This is going to require a group of
modifications to the cloud base, including modifying the partition to
support UEFI and a disk label change to GPT. With this change in
place, the images will have greater flexibility to support file
systems, such as btrfs, for boot across a number of supported
providers and environments.

* To have a consistent configuration across all the architectures
* Allows the same image to be booted using either UEFI or legacy BIOS.
* Allow easier migration from one environment to another where there
is potentially a change in boot loader.
* Use the same documentation and commands for the available cloud
architectures instead of having special cases for different
environments.
* Align with images generated by COSA, KIWI, and OSBuild on how the
GRUB configuration files are used.
* Align with other installation methods on how the partitions under
<code>/boot</code> are defined
* Align with other distributions, like CentOS and openSUSE, on support
for GRUB configuration

== Scope ==

* Proposal owners:
** Submit PRs for Cloud Edition kickstarts to produce hybrid boot.
* Release engineering: [https://pagure.io/releng/issue/10143 #10143]
* Policies and guidelines: N/A
* Trademark approval: N/A

== Upgrade/compatibility impact ==

Change will not affect upgrades.


== How To Test ==

Once the change lands in Rawhide, spin up the images in AWS, GCP, and
KVM/OpenStack to test to see systems boot and run. Where possible,
test images on cloud virtual machines types where both boot methods are
supported.

Verify that the general data partition is properly grown in the case
that the root volume is larger than the image default.

== User Experience ==

* Mostly transparent.
* Consistent recovery experience with other distributions and builds
of Fedora Linux.

== Dependencies ==

* fedora-kickstarts

== Documentation ==

No extra documentation is required reading for users. Supporting
recovery documentation is already available.

== Release Notes ==

Fedora Linux cloud images are updated to boot both UEFI and legacy
boot (BIOS) through a hybrid configuration.


-- 
Ben Cotton
He / Him / His
Fedora Program Manager
Red Hat
TZ=America/Indiana/Indianapolis

[Marcin Juszkiewicz]

W dniu 03.06.2021 o 22:35, Ben Cotton pisze:
>  https://fedoraproject.org/wiki/Changes/FedoraCloudHybridBoot
>  
>  == Summary ==
>  
>  With recent changes in public cloud widely accepting the
>  use of UEFI boot, it would be consistent to add hybrid boot in support of
>  both unifying the legacy (BIOS) and UEFI boot to the Fedora Linux
>  cloud base images.
>   
>  == Detailed Description ==
>  The Fedora Cloud Edition image will be updated to be configured with
>  multiple partitions and a GPT label instead of one single partition
>  and implicit MBR.
>  
>  The partition order will be:
>  
>  # A BIOS boot partition
>  # An EFI System partition
>  # A general data partition 
Please make first partition at least 4MB in size. Those Arm/AArch64 
systems which store bootloaders on boot media will have a space for it 
(as some already read from around that area).

[Neal Gompa]

On Thu, Jun 3, 2021 at 4:53 PM Marcin Juszkiewicz
<mjuszkiewicz(a)redhat.com&gt; wrote:
>  W dniu 03.06.2021 o 22:35, Ben Cotton pisze:
>  > https://fedoraproject.org/wiki/Changes/FedoraCloudHybridBoot
>  >
>  > == Summary ==
>  >
>  > With recent changes in public cloud widely accepting the
>  > use of UEFI boot, it would be consistent to add hybrid boot in support of
>  > both unifying the legacy (BIOS) and UEFI boot to the Fedora Linux
>  > cloud base images.
>  >
>
>  > == Detailed Description ==
>  > The Fedora Cloud Edition image will be updated to be configured with
>  > multiple partitions and a GPT label instead of one single partition
>  > and implicit MBR.
>  >
>  > The partition order will be:
>  >
>  > # A BIOS boot partition
>  > # An EFI System partition
>  > # A general data partition
>
>  Please make first partition at least 4MB in size. Those Arm/AArch64
>  systems which store bootloaders on boot media will have a space for it
>  (as some already read from around that area). 
Sure we can, but for AArch64 images, wouldn't we just be UEFI only
anyway? I think we already produce these images as UEFI only for
AArch64...




--
真実はいつも一つ！/ Always, there's only one truth!

[Peter Robinson]

On Thu, Jun 3, 2021 at 10:47 PM Neal Gompa <ngompa13(a)gmail.com&gt; wrote:
>  On Thu, Jun 3, 2021 at 4:53 PM Marcin Juszkiewicz
>  <mjuszkiewicz(a)redhat.com&gt; wrote:
>  >
>  > W dniu 03.06.2021 o 22:35, Ben Cotton pisze:
>  > > https://fedoraproject.org/wiki/Changes/FedoraCloudHybridBoot
>  > >
>  > > == Summary ==
>  > >
>  > > With recent changes in public cloud widely accepting the
>  > > use of UEFI boot, it would be consistent to add hybrid boot in support of
>  > > both unifying the legacy (BIOS) and UEFI boot to the Fedora Linux
>  > > cloud base images.
>  > >
>  >
>  > > == Detailed Description ==
>  > > The Fedora Cloud Edition image will be updated to be configured with
>  > > multiple partitions and a GPT label instead of one single partition
>  > > and implicit MBR.
>  > >
>  > > The partition order will be:
>  > >
>  > > # A BIOS boot partition
>  > > # An EFI System partition
>  > > # A general data partition
>  >
>  > Please make first partition at least 4MB in size. Those Arm/AArch64
>  > systems which store bootloaders on boot media will have a space for it
>  > (as some already read from around that area).
>
>  Sure we can, but for AArch64 images, wouldn't we just be UEFI only
>  anyway? I think we already produce these images as UEFI only for
>  AArch64... 
Correct.

[Chris Murphy]

On Thu, Jun 3, 2021 at 2:53 PM Marcin Juszkiewicz
<mjuszkiewicz(a)redhat.com&gt; wrote:
>  
> > The partition order will be:
>
>  
> > # A BIOS boot partition
> > # An EFI System partition
> > # A general data partition
>  
> Please make first partition at least 4MB in size. Those
Arm/AArch64
> systems which store bootloaders on boot media will have a space for it
> (as some already read from around that area).

I'm confused what image(s) you're referring to because, e.g.
Fedora-Cloud-Base-Rawhide-20210621.n.0.aarch64.raw has this partition
scheme:

Number  Start (sector)    End (sector)  Size       Code  Name
   1            2048         1230847   600.0 MiB   EF00  EFI System Partition
   2         1230848         3327999   1024.0 MiB  8300
   3         3328000        10483711   3.4 GiB     8300


Do you want the 1st partition to also have BIOS Boot? (partition type
guid 21686148-6449-6E6F-744E-65656445464)   GRUB maintainers have said
1 MiB is sufficient in the past; so I just want to make sure the first
partition you're referring to should have both this particular type
GUID and be 4 MiB? I don't think GRUB has exclusivity over this guid,
and was always intended to be generic, I'm just not aware of any
bootloader that uses it.

Also, the scope of the hybrid UEFI/BIOS change is limited to x86_64,
while we could incidentally add BIOS Boot to the aarch64 images, I
don't expect we'd actually put anything there. It'd be outside the
scope of the change proposal.


-- 
Chris Murphy

[Chris Murphy]

On Mon, Jun 21, 2021 at 9:43 AM Chris Murphy <lists(a)colorremedies.com&gt; wrote:
> I don't think GRUB has exclusivity over this guid,
>  and was always intended to be generic, I'm just not aware of any
>  bootloader that uses it. 
any ^other bootloader

-- 
Chris Murphy

[Marcin Juszkiewicz]

W dniu 21.06.2021 o 17:43, Chris Murphy pisze:
> > Please make first partition at least 4MB in size. Those
> Arm/AArch64
> > systems which store bootloaders on boot media will have a space for it
> > (as some already read from around that area).
>  I'm confused what image(s) you're referring 
Sorry, my mistake. I used too many images recently and missed 'cloud' in 
name.