< Changes
Enable bootupd for Fedora Silverblue & Kinoite
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
By design, ostree does not manage bootloader updates as they can not (yet) happen in a transactional, atomic and safe fashion. Thus bootupd (https://github.com/coreos/bootupd) was created to solve this issue and enable admin-lead bootloader updates. This change is about enabling bootupd integration in Fedora Silverblue and Fedora Kinoite to make bootloader updates easier.
Owner
- Name: Timothée Ravier, Tomáš Popela, Colin Walters
- Email: <siosm@fedoraproject.org>, <tpopela@fedoraproject.org>, <walters@fedoraproject.org>
Current status
- Targeted release: Fedora Linux 38
- Last updated: 2022-11-10
- FESCo issue: <will be assigned by the Wrangler>
- Tracker bug: <will be assigned by the Wrangler>
- Release notes tracker: <will be assigned by the Wrangler>
Detailed Description
Adding bootupd full bootupd support has two immediate benefits:
- User will be able to easily update the bootloader on their system. This will let them apply Secure Boot dbx updates that block old bootloaders with known vulnerabilities from loading. See:
- We can start planning for the removal of the ostree-grub2 package from the images to solve the "all deployments are shown twice in GRUB" issue. This bug comes from the fact that old GRUB versions that do not have BLS support and we thus can not only rely on BLS support in ostree to generate boot and have to also update the grub configuration for every updates via the scripts in the ostree-grub2 package. This has already (indirectly) caused a major upgrade issue on Silverblue/Kinoite requiring manual interventions from all users. See:
Note that we can not yet enable unattended bootloader updates as even though bootupd tries hard hard to make those updates as safe as possible, it is currently not possible that they are safe if the system crashes (or loses power) at the wrong time. The following change in shim (https://github.com/rhboot/shim/pull/502) should help with that.
Thus bootloaders updates will remain a manually user triggered operation for now.
Also note that this change currently relies on the image being composed via rpm-ostree in unified core, which is the subject of the following change also proposed for Fedora 38: https://fedoraproject.org/wiki/Changes/FedoraSilverblueUnifiedCore
Feedback
None so far.
Benefit to Fedora
Fedora Silverblue and Fedora Kinoite users can easily do bootloaders updates (that includes security fixes) and we can remove support for legacy GRUB versions thus simplify the upgrade process and making it more reliable.
Scope
- Proposal owners: Testing of the integration and new builds. The code changes are mostly done and the integration changes are mostly already ready as bootupd has already been integrated in a similar fashion in Fedora CoreOS.
- Other developers: N/A
- Release engineering: N/A
- Policies and guidelines: N/A (not needed for this Change)
- Trademark approval: N/A (not needed for this Change)
- Alignment with Objectives: N/A
Upgrade/compatibility impact
There should be not visible change for users when upgrading. The change only impacts the way the images are composed on the server.
How To Test
We will extend the test instructions once the unified core changes have landed. You can follow: https://github.com/fedora-silverblue/issue-tracker/issues/120 and https://github.com/fedora-silverblue/issue-tracker/issues/355.
User Experience
For now, users will have to update their bootloader manually via the command line. Integration to GNOME Software and Plasma Discover might be interesting to make that easier.
Once the fallback EFI feature is available in shim (and support implemented in bootupd), we can consider implementing automated updates.
Dependencies
N/A
Contingency Plan
- Contingency mechanism: Revert the change in the rpm-ostree manifests. Owners will do it. Nothing to do for users.
- Contingency deadline: Can happen anytime.
- Blocks release? No
Documentation
We will write docs to let users update their bootloaders manually. They will look very similar to https://docs.fedoraproject.org/en-US/fedora-coreos/bootloader-updates/.
Release Notes
Will have to be written.