F41 Change Proposal: DNF and bootc in Image Mode Fedora variants (system wide)

DNF and bootc in Image Mode Fedora variants

This is a proposed Change for Fedora Linux.
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.


:link: Summary

Enhance the image-mode Fedora user experience by providing familiar DNF commands on client side and inside a container image build. Provide DNF5 alongside rpm-ostree while we slowly port functionality from rpm-ostree to DNF5.

DNF5 can be used in most cases during container builds (Containerfile/Dockerfiles) for a familiar UX. Initially DNF will point users to use rpm-ostree on a booted image-based/ostree system.

For Fedora 41, we will provide DNF5 on image-based Fedora variants (Atomic desktops, Fedora IoT, etc). We will update all layering examples to use dnf during build time when possible. Additionally to DNF we will still provide rpm-ostree as the main tool for package layering on the client side and bootc to manage transactional, in-place operating system updates using OCI/Docker container images.

DNF5 will provide a helpful error when running on an ostree/image-based booted system pointing to use rpm-ostree or to unlock the system.

This work is part of the Fedora Bootable Containers Initiative.

:link: Owner

:link: Current status

DNF5 when installed on a image-based/ostree system can be used to install RPMs if the system is unlocked, it also works on most container builds, one major exception at the moment are kernel installations and kernel updates. DNF is not part of image variants at the moment, however CoreOS is exploring adding it via: Ship dnf in FCOS and RHCOS · Issue #1687 · coreos/fedora-coreos-tracker · GitHub

Bootc allows system admins to deploy bootable containers and it’s available on the Fedora repositories.

:link: Detailed Description

Having the Fedora ecosystem (from users to release engineering) move away from DNF on image-based systems has had mixed results as it has forced sysadmins and users to not use DNF as they are accustomed to and learn a new tool to do RPM package management in their systems. This change proposal starts the process of making DNF the client side tool to manage RPMs on image-based systems in the future. To start we will provide the DNF5 package alongside rpm-ostree, giving sysadmins and users the ability to use DNF on their container builds and unlocked systems running image-based Fedora variants. We will also provide bootc to manage the image-based deployments and updates.

This proposes that:

  • DNF5 is included on image-based/ostree Fedora variants.
  • DNF5 is updated to point users to rpm-ostree on booted client systems when invoked.
  • rpm-ostree features will start being ported to DNF5.
  • We support deriving new user custom images from image-based Fedora images and installing software using DNF during builds.
  • We ship bootc on all Fedora image-based variants.

:link: Feedback

None so far.

:link: Benefit to Fedora

  • A familiar UX for rpms during container builds of image-based Fedora.
  • A new dedicated tool for image-based system updates management that follows the *nix ethos of using one thing and doing it well.
  • An initial use of DNF on booted image-based systems when the system is unlocked.

:link: Scope

  • Proposal owners:
    • Add DNF5 and bootc on all image-based/ostree variants.
    • Update DNF5 error message when called on a booted image-based/ostree system
  • Other developers:
    • The “other” here is vague, but certainly developing this so far has needed cooperation with e.g. the containers, coreos and dnf organizations etc.
  • Release engineering: Probably nothing needed so N/A #Releng issue number
  • Policies and guidelines: N/A (not needed for this Change)
  • Trademark approval: N/A (not needed for this Change)
  • Alignment with the Fedora Strategy: Aligns with the work to improve Image Mode variants of Fedora

:link: Upgrade/compatibility impact

Each edition/spin will include bootc and dnf(DNF5). However rpm-ostree will still be present, which means there is no upgrade/compatibility impact, we are adding additional tools not removing tools or functionality.

:link: Early Testing (Optional)

Do you require ‘QA Blueprint’ support? No

:link: How To Test

On a booted image-based host, run: dnf install <package> and bootc status

Inside a Dockerfile/Containerfile with a image-based Fedora variant as a base image, add a package using dnf: RUN dnf install <package>

:link: User Experience

Users of image-based Fedora variants will be able to use the dnf command on Container builds and unlocked systems.

:link: Dependencies


:link: Contingency Plan

  • Contingency mechanism: Continue to ship without DNF in some or all image-based/ostree variants.
  • Contingency deadline: Beta freeze.
  • Blocks release? No

:link: Documentation

:link: Release Notes

To be written.

Last edited by @amoloney 2024-05-21T10:25:23Z


How do you feel about the proposal as written?

  • Strongly in favor
  • In favor, with reservations
  • Neutral
  • Opposed, but could be convinced
  • Strongly opposed
0 voters

If you are in favor but have reservations, or are opposed but something could change your mind, please explain in a reply.

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I have mixed feelings about merging rpm-ostree functionality into DNF5. To me it seems like building single tool for two quite different purposes. So it kinda goes against “doing only one thing well”.

Also I am afraid that having single tool with different sub-commands and options performing differently depending on what system (in what mode) it is used can cause more confusion that it solves.

I’m not sure that tiny, composable tools are really an overall design goal.

Interesting — I see it as the opposite. Currently, there are two different ways to do the same thing (install and manage software). This brings that together into one tool which does that one thing.

But, I agree with the concern about the same commands acting differently in different circumstances. It’s important to get that UX right.

I’d like to see more of a plan here. :classic_smiley:

This change proposal has now been submitted to FESCo with ticket #3216 for voting.

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Updated the section on the proposal.

Matthew’s position is how most of us owning the proposal see it. We are also in the process to designing the UX but that will likely take some time and is out of scope on this proposal. But you can follow the issues related to DNF/Bootc here: Issues · fedora / bootc / Issue Tracker · GitLab

This change has been accepted by FESCo for Fedora Linux 41. A full list of approved changes to date can be found on the Change Set Page.

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