Consumer Guide — Using These Actions in Your Own bootc Image#

How to wire projectbluefin/actions into a custom Fedora-based bootc image repo.

Contents#

Two paths
Path 1 — Full reusable workflow
Path 2 — Composite actions à la carte
Versioning and SHA pinning
Known constraints
Checklist before going live
Getting help

Sub-file (load as needed):

consumer-guide/upgrade-and-migration.md — upgrade test gate, migration test, dakota notes, live consumer examples

Two paths#

Path	When to use
Full reusable workflow	Your image follows the bluefin/aurora build model (Fedora base, Justfile-driven, GHCR push)
Composite actions à la carte	You have a custom pipeline, non-Fedora base, or multi-arch needs

Path 1 — Full reusable workflow#

Prerequisites#

Your repo must satisfy a Justfile contract: the reusable workflow calls specific recipes from your checked-out repo. All recipe signatures must match exactly.

Recipe	Signature	What it must do
`check`	`just check`	Validate repo health (lint, format); exit non-zero on failure
`image_name`	`just image_name <base> <stream> <flavor>`	Print the image name to stdout (e.g. `my-image`)
`generate-default-tag`	`just generate-default-tag <stream> <ghcr> [kernel_pin]`	Print the primary OCI tag (e.g. `latest`)
`generate-build-tags`	`just generate-build-tags <image> <stream> <flavor> [kernel_pin] <ghcr> [version] <event> <number>`	Print newline-separated alias tags
`setup-cache`	`just setup-cache <base> <stream> <ghcr> <event>`	Print the cache key fragment; optionally configure OCI layer cache
`build-ghcr`	`just build-ghcr <image> <stream> <flavor> [kernel_pin]`	Build the image into local podman storage as `<image>:<default-tag>`
`tag-images`	`just tag-images <image_name> <default_tag> <tags>`	Apply alias tags to the locally built image

Easiest path: fork the bluefin Justfile as a starting point and adapt it for your image name and base.

Minimal caller workflow#

# .github/workflows/build.yml
name: Build My Image

on:
  push:
    branches: [main]
  workflow_dispatch:

jobs:
  build:
    uses: projectbluefin/actions/.github/workflows/reusable-build.yml@v1
    secrets: inherit
    with:
      brand_name: my-image # must match your image_name recipe output
      stream_name: latest # stable | latest | beta | testing
      image_flavors: '["main"]' # JSON array; each entry is passed as <flavor> to Justfile
      architecture: '["x86_64"]' # '["x86_64"]' or '["x86_64", "aarch64"]'

Full inputs reference#

Input	Required	Default	Description
`brand_name`	no	`bluefin`	Passed as `<base>` to all Justfile recipes
`stream_name`	yes	—	`stable`, `latest`, `beta`, or `testing`
`image_flavors`	no	`'["main", "nvidia-open"]'`	JSON array of flavor strings
`architecture`	no	`'["x86_64"]'`	JSON array; `aarch64` requires self-hosted ARM runner
`kernel_pin`	no	`""`	Full kernel version string; passed through to build and tag recipes
`pr_number`	no	`""`	Set by `e2e-dispatch.yml` — scopes tags to the PR number

Output#

outputs:
  digests: # Nested JSON: { "my-image-main": { "amd64": "sha256:abc..." } }

Consume downstream in a signing or release job:

jobs:
  build:
    uses: projectbluefin/actions/.github/workflows/reusable-build.yml@v1
    secrets: inherit
    with:
      brand_name: my-image
      stream_name: stable
      image_flavors: '["main"]'
      architecture: '["x86_64"]'

  release:
    needs: build
    runs-on: ubuntu-latest
    steps:
      - run: echo "Digests = ${{ needs.build.outputs.digests }}"

Path 2 — Composite actions à la carte#

Use individual actions when you need more control: different base distro (CentOS, Alpine), multi-arch manifest, non-Justfile build system, or custom signing.

Action catalog#

Action	`uses:` path	Purpose
`setup-runner`	`bootc-build/setup-runner@v1`	Update podman, set up BTRFS storage, install tools
`dnf-cache`	`bootc-build/dnf-cache@v1`	Restore/save buildah layer cache
`preflight`	`bootc-build/preflight@v1`	Validate registry auth, normalize image refs
`detect-changes`	`bootc-build/detect-changes@v1`	Detect changed paths, compute image-flavor build matrix
`validate-pr`	`bootc-build/validate-pr@v1`	Run just check, shellcheck, hadolint, pre-commit
`generate-tags`	`bootc-build/generate-tags@v1`	Generate shared Bluefin/Fedora OCI alias tags
`push-image`	`bootc-build/push-image@v1`	Push with retry, digest capture, skopeo alias tags
`create-manifest`	`bootc-build/create-manifest@v1`	Multi-arch OCI manifest index assembly
`sign-and-publish`	`bootc-build/sign-and-publish@v1`	Cosign (keyless or key) + Syft SBOM + attestation
`rechunk`	`bootc-build/rechunk@v1`	rpm-ostree `zstd:chunked` rechunking with delta support
`chunka`	`bootc-build/chunka@v1`	OCI-native chunkah rechunking (no rpm-ostree needed)
`ghcr-cleanup`	`bootc-build/ghcr-cleanup@v1`	Prune old/untagged GHCR images

generate-tags is for Path 2 and other custom pipelines. Path 1 does not use it; tag generation stays in the caller's Justfile.

Minimal custom pipeline#

jobs:
  build:
    runs-on: ubuntu-24.04
    permissions:
      contents: read
      packages: write
      id-token: write # required for keyless cosign signing

    steps:
      - uses: actions/checkout@v4

      - uses: projectbluefin/actions/bootc-build/setup-runner@v1
        with:
          storage-backend: btrfs
          install-tools: '["cosign", "oras", "syft"]'

      - uses: projectbluefin/actions/bootc-build/dnf-cache@v1
        id: dnf-cache-restore
        with:
          action: restore
          cache-name: my-image-42
          image-flavor: ${{ matrix.image_flavor }}

      - name: Build image
        run: |
          sudo podman build \
            --tag my-image:latest \
            --label "org.opencontainers.image.version=42.$(date +%Y%m%d)" \
            .

      - uses: projectbluefin/actions/bootc-build/dnf-cache@v1
        with:
          action: save
          cache-name: my-image-42
          image-flavor: ${{ matrix.image_flavor }}

      - if: github.event_name != 'pull_request'
        uses: projectbluefin/actions/bootc-build/push-image@v1
        id: push
        with:
          image-name: my-image
          tags: "latest"
          github-token: ${{ secrets.GITHUB_TOKEN }}

      - if: github.event_name != 'pull_request'
        uses: projectbluefin/actions/bootc-build/sign-and-publish@v1
        with:
          image-ref: ghcr.io/${{ github.repository_owner }}/my-image
          digest: ${{ steps.push.outputs.digest }}
          github-token: ${{ secrets.GITHUB_TOKEN }}
          signing-mode: keyless
          generate-sbom: "true"

Multi-arch pipeline (with manifest)#

strategy:
  matrix:
    arch: [x86_64, aarch64]
    include:
      - arch: x86_64
        runner: ubuntu-24.04
      - arch: aarch64
        runner: ubuntu-24.04-arm

jobs:
  build:
    runs-on: ${{ matrix.runner }}
    outputs:
      digest: ${{ steps.push.outputs.digest }}
    # ... build and push per-arch image ...

  manifest:
    needs: build
    runs-on: ubuntu-24.04
    steps:
      - uses: projectbluefin/actions/bootc-build/create-manifest@v1
        with:
          image-name: my-image
          tags: "latest"
          digests-json: >-
            {
              "amd64": "${{ needs.build.outputs.digest-amd64 }}",
              "arm64": "${{ needs.build.outputs.digest-arm64 }}"
            }
          github-token: ${{ secrets.GITHUB_TOKEN }}

Note: create-manifest does not install its dependencies. Ensure podman and jq are available on the runner.

Versioning and SHA pinning#

Pin to @v1 for stability. To test against a feature branch before it merges:

uses: projectbluefin/actions/.github/workflows/reusable-build.yml@abc1234

Move back to @v1 after the branch merges. Renovate manages SHA bumps automatically.

Known constraints#

Constraint	Detail
Fedora only (reusable workflow)	The rechunk step uses rpm-ostree and assumes Fedora OSTree base. CentOS/Alpine users should use composite actions à la carte with `chunka`
Justfile contract is strict	All 7 required recipes must exist with the exact expected signatures
`aarch64` requires ARM runner	Self-hosted or GitHub-hosted `ubuntu-24.04-arm`; not included in the default free-tier
Registry hardcoded to GHCR	The `IMAGE_REGISTRY` env var is `ghcr.io/${{ github.repository_owner }}`; override only via composite actions
CentOS Stream requires explicit compression	Set `force-compression: true` on both `chunka` and `push-image`. Fedora consumers must leave both at the default `false`
SBOM on all non-PR streams	`testing` stream builds include SBOM — weekly promotions retag testing digests to stable, so SBOM coverage is required end-to-end
Multi-arch matrix stays in the consumer workflow	Do not move matrix orchestration into shared actions. Shared actions are per-arch steps; the matrix stays in the consumer workflow

Checklist before going live#

Getting help#

File issues at projectbluefin/actions
Working examples: projectbluefin/bluefin (Path 1) and projectbluefin/bluefin-lts (Path 2 à la carte)