There is one branch for each stream. The default branch is testing-devel, on which all development happens. See the design and tooling docs for more information about streams.

All file changes in testing-devel are propagated to other branches (to bodhi-updates through config-bot, and to testing through usual promotion), with the following exceptions:

manifest.yaml: contains the stream "identity", such as the ref, additional commit metadata, and yum input repos.
lockfiles (manifest-lock.* files): lockfiles are imported from bodhi-updates to testing-devel. Overrides (manifest-lock.overrides.*) are manually curated.

Layout

We intend for Fedora CoreOS to be used directly for a wide variety of use cases. However, we also want to support "custom" derivatives such as Fedora Silverblue, etc. Hence the configuration in this repository is split up into reusable "layers" and components on the rpm-ostree side.

To derive from this repository, the recommendation is to add it as a git submodule. Then create your own manifest.yaml which does include: fedora-coreos-config/ignition-and-ostree.yaml for example. You will also want to create an overlay.d and symlink in components in this repository's overlay.d.

Overriding packages

By default, all packages for FCOS come from the stable Fedora repos. However, it is sometimes necessary to either hold back some packages, or pull in fixes ahead of Bodhi. To add such overrides, one needs to add the packages to manifest-lock.overrides.yaml (there are also arch-specific variants of these files for the rare occasions the override should only apply to a specific arch).

Note that comments are not preserved in these files. The lockfile supports arbitrary keys under the metadata key to carry information. Some keys are semantically meaningful to humans or other tools.

Fast-tracking

Example:

packages:
  selinux-policy:
    evra: 34.10-1.fc34.noarch
    metadata:
      type: fast-track
      bodhi: https://bodhi.fedoraproject.org/updates/FEDORA-2021-f014ca8326
      reason: https://github.com/coreos/fedora-coreos-tracker/issues/850
  selinux-policy-targeted:
    evra: 34.10-1.fc34.noarch
    metadata:
      type: fast-track
      # you don't have to repeat the other keys for related packages

Whenever possible, it is important that the package be submitted as an update to Bodhi so that we don't have to carry the override for a long time.

Fast-tracked packages will automatically be removed by the remove-graduated-overrides GitHub Action in this repo once they reach the stable Fedora repos (or newer versions). They are detected by the type: fast-track key.

Pinning

Example:

packages:
  dracut:
      evr: 053-5.fc34
      metadata:
        type: pin
        reason: https://github.com/coreos/fedora-coreos-tracker/issues/842
  dracut-network:
      evr: 053-5.fc34
      metadata:
        type: pin
        reason: https://github.com/coreos/fedora-coreos-tracker/issues/842

All pinned packages must have a reason key containing more information about why the pin is necessary.

Once an override PR is merged, coreos-koji-tagger will automatically tag overridden packages into the pool.

Adding packages to the OS

Since testing-devel is directly promoted to testing, it must always be in a known state. The way we enforce this is by requiring all packages to have a corresponding entry in the lockfile.

Therefore, to add new packages to the OS, one must also add the corresponding entries in the lockfiles:

for packages which should follow Bodhi updates, place them in manifest-lock.$basearch.json
for packages which should remain pinned, place them in manifest-lock.overrides.$basearch.yaml

There will be better tooling to come to enable this, though one easy way to do this is for now:

add packages to the correct YAML manifest
run cosa fetch --update-lockfile
commit only the new package entries

Moving to a new major version (N) of Fedora

Create a rebase checklist in fedora-coreos-tracker.

CoreOS CI

Pull requests submitted to this repo are tested by CoreOS CI. You can see the pipeline executed in .cci.jenkinsfile. For more information, including interacting with CI, see the CoreOS CI documentation.