Re: F39 proposal: Register EC2 Cloud Images with uefi-preferred AMI flag (Self-Contained Change proposal)

[Robbie Harwood]

Ben Cotton <bcotton(a)redhat.com&gt; writes:

>  https://fedoraproject.org/wiki/Changes/CloudEC2UEFIPreferred
>
>  This document represents a proposed Change. As part of the Changes
>  process, proposals are publicly announced in order to receive
>  community feedback. This proposal will only be implemented if approved
>  by the Fedora Engineering Steering Committee.
>
>  == Summary ==
>  A new feature of EC2 is to be able to register AMIs with a boot mode
>  of `uefi-preferred` rather than picking one of `bios` or `uefi`. In
>  EC2, aarch64 has always been UEFI, while x86-64 started out as BIOS
>  only and some instance types have recently begun to support booting in
>  UEFI mode. Previously, an AMI had to pick if it was UEFI or BIOS. With
>  `uefi-preferred` it allows an AMI to launch with whatever firmware
>  stack is available for the instance type, preferring UEFI when UEFI is
>  an option.
>
>  This proposal is to register the Fedora EC2 images with
>  `uefi-preferred`, having the effect of switching to booting in UEFI
>  mode on x86-64 in EC2 where available.
>
>  == Owner ==
>  * Name: [[User:Trawets| Stewart Smith]] [[User:Davdunc| David Duncan]]
>  * Email: trawets(a)amazon.com
>
>
>  == Detailed Description ==
>  Some features of some EC2 instance types (such as secure boot) are
>  only available in UEFI mode. There is also the standard set of
>  advantages of UEFI over BIOS. All aarch64 instance types in EC2 have
>  always been UEFI, while all x86-64 instance types were historically
>  all BIOS. Recently, some x86-64 instance types have started to support
>  UEFI mode. This was originally implemented as an option for instance
>  launches and AMI registration. An AMI could state that it should be
>  booted in UEFI mode. An AMI registered for UEFI would *not* boot on
>  BIOS-only instance types. This meant that if you wanted to make
>  available an OS that could boot on all instance types, you'd need a
>  trio of AMIs: aarch64 UEFI, x86-64 BIOS, and x86-64 UEFI.
>
>  With the `uefi-preferred` boot mode, one AMI registered for x86-64
>  will boot on UEFI where possible, but also boot BIOS if the instance
>  type doesn't support UEFI.
>
>  By registering Fedora AMIs with this boot mode, EC2 features that
>  require UEFI (such as Secure Boot and NitroTPM) will be able to be
>  used in Fedora, while still maintaining compatibility with BIOS only
>  instance types.
>
>  == Feedback ==
>  We have started registering Amazon Linux 2023 AMIs with this boot
>  mode, albeit quite late in the development cycle of AL2023 due to the
>  timing of when the `uefi-preferred` boot mode flag was added to EC2.
>
>  == Benefit to Fedora ==
>  UEFI is becoming more ubiquitous amongst hardware, and operating under
>  UEFI inside EC2 unlocks an increasing number of features such as
>  Secure Boot and NitroTPM. The benefit for Fedora is a more uniform
>  experience across cloud and non-cloud environments, simplifying the
>  boot and runtime software stack. 
On behalf of the Fedora bootloader maintainers, thank you for this
change.

Be well,
--Robbie