Use Linux architecture names in output artifact filenames:

Tinkerbell iPXE scripts are built around architecture naming in a specific way.
x86_64 and aarch64. This makes CaptainOS backward compatible.

Signed-off-by: Jacob Weinstock <jakobweinstock@gmail.com>

Author: jacobweinstock

.github/workflows/ci.yml

@@ -279,6 +279,11 @@ jobs:
       fail-fast: false
       matrix:
         arch: [amd64, arm64]
+        include:
+          - arch: amd64
+            output_arch: x86_64
+          - arch: arm64
+            output_arch: aarch64
     env:
       ARCH: ${{ matrix.arch }}
       KERNEL_MODE: skip
@@ -339,7 +344,7 @@ jobs:
       - name: Stage initramfs for ISO build
         run: |
           mkdir -p "mkosi.output/initramfs/${KERNEL_VERSION}/${{ matrix.arch }}"
-          cp "out/initramfs-${KERNEL_VERSION}-${{ matrix.arch }}.cpio.zst" \
+          cp "out/initramfs-${KERNEL_VERSION}-${{ matrix.output_arch }}" \
              "mkosi.output/initramfs/${KERNEL_VERSION}/${{ matrix.arch }}/image.cpio.zst"
 
       - name: Install Python dependencies
@@ -352,7 +357,7 @@ jobs:
         uses: actions/upload-artifact@v4
         with:
           name: iso-${{ matrix.arch }}
-          path: out/captainos-${{ env.KERNEL_VERSION }}-${{ matrix.arch }}.iso
+          path: out/captainos-${{ env.KERNEL_VERSION }}-${{ matrix.output_arch }}.iso
           retention-days: 1
 
   # -------------------------------------------------------------------

README.md

@@ -16,7 +16,7 @@ It is built with [mkosi](https://github.com/systemd/mkosi), producing a minimal
 
 ## How it works
 
-1. The machine PXE boots the kernel (`vmlinuz`) and initramfs (`initramfs.cpio.zst`) or runs the UEFI-bootable ISO image
+1. The machine PXE boots the kernel (`vmlinuz`) and initramfs (`initramfs`) or runs the UEFI-bootable ISO image
 2. A custom `/init` script transitions the rootfs to tmpfs, then exec's systemd
 3. systemd-networkd configures DHCP on all ethernet interfaces
 4. containerd starts, then `tink-agent-setup` pulls the tink-agent container image (configured via kernel cmdline), extracts the binary, and runs it as a host process
@@ -87,7 +87,7 @@ commands:
 
 Output artifacts are placed in `out/`:
 
-- `out/initramfs-<arch>.cpio.zst` — the initramfs
+- `out/initramfs-<arch>` — the initramfs
 - `out/vmlinuz-<arch>` — the kernel
 - `out/captainos-<arch>.iso` — UEFI-bootable ISO image
 - `out/sha256sums-<arch>.txt` — SHA-256 checksums
@@ -102,8 +102,8 @@ Three multi-arch OCI indexes are published per build:
 
 | Image | Tag | Contents |
 | --- | --- | --- |
-| amd64-only | `vX.Y.Z-<sha7>-amd64` | vmlinuz, initramfs, ISO, checksums (amd64) |
-| arm64-only | `vX.Y.Z-<sha7>-arm64` | vmlinuz, initramfs, ISO, checksums (arm64) |
+| amd64-only | `vX.Y.Z-<sha7>-amd64` | vmlinuz, initramfs, ISO, checksums (x86_64) |
+| arm64-only | `vX.Y.Z-<sha7>-arm64` | vmlinuz, initramfs, ISO, checksums (aarch64) |
 | combined | `vX.Y.Z-<sha7>` | all artifacts from both architectures |
 
 Each artifact file is pushed as its own OCI layer. Deterministic tar creation (zeroed metadata) ensures identical layer digests across per-arch and combined images, so registries deduplicate shared blobs — the combined image adds zero additional storage.
@@ -119,8 +119,8 @@ When a `v*` tag is pushed, the release workflow:
 
 1. Pulls the combined OCI image (both architectures)
 2. Attaches all artifacts as downloadable files on the GitHub Release page:
-   - `vmlinuz-amd64`, `initramfs-amd64.cpio.zst`, `captainos-amd64.iso`, `sha256sums-amd64.txt`
-   - `vmlinuz-arm64`, `initramfs-arm64.cpio.zst`, `captainos-arm64.iso`, `sha256sums-arm64.txt`
+   - `vmlinuz-x86_64`, `initramfs-x86_64`, `captainos-x86_64.iso`, `sha256sums-x86_64.txt`
+   - `vmlinuz-aarch64`, `initramfs-aarch64`, `captainos-aarch64.iso`, `sha256sums-aarch64.txt`
 3. Tags all three OCI images with the clean release version (`vX.Y.Z`, `vX.Y.Z-amd64`, `vX.Y.Z-arm64`)
 
 ### Release subcommands

captain/artifacts.py

@@ -39,7 +39,7 @@ def collect_kernel(cfg: Config, logger: StageLogger | None = None) -> None:
     vmlinuz_files = sorted(vmlinuz_dir.glob("vmlinuz-*")) if vmlinuz_dir.is_dir() else []
     if vmlinuz_files:
         vmlinuz_src = vmlinuz_files[0]
-        vmlinuz_dst = out / f"vmlinuz-{cfg.kernel_version}-{cfg.arch}"
+        vmlinuz_dst = out / f"vmlinuz-{cfg.kernel_version}-{cfg.arch_info.output_arch}"
         shutil.copy2(vmlinuz_src, vmlinuz_dst)
         _log.log(f"kernel: {vmlinuz_dst} ({_human_size(vmlinuz_dst.stat().st_size)})")
     else:
@@ -53,7 +53,7 @@ def collect_initramfs(cfg: Config, logger: StageLogger | None = None) -> None:
     cpio_files = sorted(cfg.initramfs_output.glob("*.cpio*"))
     if cpio_files:
         initrd_src = cpio_files[0]
-        initrd_dst = out / f"initramfs-{cfg.kernel_version}-{cfg.arch}.cpio.zst"
+        initrd_dst = out / f"initramfs-{cfg.kernel_version}-{cfg.arch_info.output_arch}"
         shutil.copy2(initrd_src, initrd_dst)
         _log.log(f"initramfs: {initrd_dst} ({_human_size(initrd_dst.stat().st_size)})")
     else:
@@ -68,7 +68,7 @@ def collect_iso(cfg: Config, logger: StageLogger | None = None) -> None:
     iso_files = sorted(iso_dir.glob("*.iso")) if iso_dir.is_dir() else []
     if iso_files:
         iso_src = iso_files[0]
-        iso_dst = out / f"captainos-{cfg.kernel_version}-{cfg.arch}.iso"
+        iso_dst = out / f"captainos-{cfg.kernel_version}-{cfg.arch_info.output_arch}.iso"
         shutil.copy2(iso_src, iso_dst)
         _log.log(f"iso: {iso_dst} ({_human_size(iso_dst.stat().st_size)})")
 

captain/cli/_commands.py

@@ -271,18 +271,18 @@ def _cmd_checksums(cfg: Config, _extra_args: list[str], args: object = None) ->
     else:
         # Default mode: produce checksums for the selected architecture.
         out = cfg.output_dir
-        arch = cfg.arch
+        oarch = cfg.arch_info.output_arch
         kver = cfg.kernel_version
         arch_files = [
-            out / f"vmlinuz-{kver}-{arch}",
-            out / f"initramfs-{kver}-{arch}.cpio.zst",
-            out / f"captainos-{kver}-{arch}.iso",
+            out / f"vmlinuz-{kver}-{oarch}",
+            out / f"initramfs-{kver}-{oarch}",
+            out / f"captainos-{kver}-{oarch}.iso",
         ]
         existing = [f for f in arch_files if f.is_file()]
         if not existing:
-            clog.err(f"No artifacts found for {kver}-{arch} in {out}")
+            clog.err(f"No artifacts found for {kver}-{oarch} in {out}")
             raise SystemExit(1)
-        dest = Path(output) if output else out / f"sha256sums-{kver}-{arch}.txt"
+        dest = Path(output) if output else out / f"sha256sums-{kver}-{oarch}.txt"
         artifacts.collect_checksums(existing, dest, logger=clog)
     clog.log("Checksums complete!")
 

captain/cli/_stages.py

@@ -161,7 +161,7 @@ def _build_iso_stage(cfg: Config) -> None:
         return
 
     # --- idempotency --------------------------------------------------
-    iso_path = cfg.iso_output / f"captainos-{cfg.kernel_version}-{cfg.arch}.iso"
+    iso_path = cfg.iso_output / f"captainos-{cfg.kernel_version}-{cfg.arch_info.output_arch}.iso"
     if iso_path.is_file() and not cfg.force_iso:
         isolog.log(f"ISO already built: {iso_path} (use --force-iso to rebuild)")
         return

captain/config.py

@@ -187,7 +187,7 @@ def mkosi_output(self) -> Path:
 
     @property
     def initramfs_output(self) -> Path:
-        """Per-version, per-arch directory for mkosi initramfs output (image.cpio.zst)."""
+        """Per-version, per-arch directory for mkosi initramfs output."""
         return self.project_dir / "mkosi.output" / "initramfs" / self.kernel_version / self.arch
 
     @property

captain/iso.py

@@ -34,7 +34,7 @@ def _grub_cfg(arch: str) -> str:
 
         menuentry "CaptainOS" {{
             linux /boot/vmlinuz {console} 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
-            initrd /boot/initramfs.cpio.zst
+            initrd /boot/initramfs
         }}
     """)
 
@@ -70,7 +70,7 @@ def build(cfg: Config) -> None:
         │   ├── grub/
         │   │   └── grub.cfg
         │   ├── vmlinuz
-        │   └── initramfs.cpio.zst
+        │   └── initramfs
 
     ``grub-mkrescue`` turns this into a bootable ISO with an embedded
     EFI System Partition.
@@ -95,14 +95,14 @@ def build(cfg: Config) -> None:
 
     # Copy kernel and initramfs
     shutil.copy2(vmlinuz, boot_dir / "vmlinuz")
-    shutil.copy2(initramfs, boot_dir / "initramfs.cpio.zst")
+    shutil.copy2(initramfs, boot_dir / "initramfs")
 
     # Write GRUB configuration
     (grub_dir / "grub.cfg").write_text(_grub_cfg(cfg.arch))
 
     # Build the ISO
     iso_dir = ensure_dir(cfg.iso_output)
-    iso_path = iso_dir / f"captainos-{cfg.kernel_version}-{cfg.arch}.iso"
+    iso_path = iso_dir / f"captainos-{cfg.kernel_version}-{cfg.arch_info.output_arch}.iso"
 
     _log.log(f"Building ISO with grub-mkrescue ({grub_platform})...")
     grub_mkrescue = shutil.which("grub-mkrescue")

captain/oci/_build.py

@@ -10,6 +10,7 @@
 
 from captain import artifacts, buildah
 from captain.log import StageLogger
+from captain.util import get_arch_info
 
 
 def _deterministic_tar(file_path: Path, output_dir: Path) -> Path:
@@ -47,19 +48,20 @@ def _collect_arch_artifacts(
     # Collect kernel
     vmlinuz_dir = project_dir / "mkosi.output" / "kernel" / kernel_version / arch
     vmlinuz_files = sorted(vmlinuz_dir.glob("vmlinuz-*")) if vmlinuz_dir.is_dir() else []
-    vmlinuz_dst = out / f"vmlinuz-{kernel_version}-{arch}"
+    oarch = get_arch_info(arch).output_arch
+    vmlinuz_dst = out / f"vmlinuz-{kernel_version}-{oarch}"
     if vmlinuz_files:
         shutil.copy2(vmlinuz_files[0], vmlinuz_dst)
         logger.log(f"kernel: {vmlinuz_dst}")
     else:
         logger.warn(f"No kernel image found for {arch}")
 
     arch_files = [
-        out / f"vmlinuz-{kernel_version}-{arch}",
-        out / f"initramfs-{kernel_version}-{arch}.cpio.zst",
-        out / f"captainos-{kernel_version}-{arch}.iso",
+        out / f"vmlinuz-{kernel_version}-{oarch}",
+        out / f"initramfs-{kernel_version}-{oarch}",
+        out / f"captainos-{kernel_version}-{oarch}.iso",
     ]
-    checksums_path = out / f"sha256sums-{kernel_version}-{arch}.txt"
+    checksums_path = out / f"sha256sums-{kernel_version}-{oarch}.txt"
     artifacts.collect_checksums(arch_files, checksums_path, logger=logger)
 
     push_files = [*arch_files, checksums_path]

captain/qemu.py

@@ -65,8 +65,8 @@ def run_qemu(cfg: Config, args: argparse.Namespace | None = None) -> None:
     :mod:`configargparse`.  When provided, Tinkerbell kernel cmdline
     parameters are drawn from it instead of the environment.
     """
-    kernel = cfg.output_dir / f"vmlinuz-{cfg.kernel_version}-{cfg.arch}"
-    initrd = cfg.output_dir / f"initramfs-{cfg.kernel_version}-{cfg.arch}.cpio.zst"
+    kernel = cfg.output_dir / f"vmlinuz-{cfg.kernel_version}-{cfg.arch_info.output_arch}"
+    initrd = cfg.output_dir / f"initramfs-{cfg.kernel_version}-{cfg.arch_info.output_arch}"
 
     missing: list[str] = []
     if not kernel.is_file():

captain/tools.py

@@ -167,7 +167,7 @@ def download_all(cfg: Config) -> None:
 
     _log.log("Tool download complete.")
 
-    # NOTE: UPX compression is not used. The final image is cpio.zst, and zstd
-    # compresses raw ELF binaries better than UPX-packed ones (UPX output looks
-    # like random data to zstd, defeating its compression).
+    # NOTE: UPX compression is not used. The initramfs is a zstd-compressed
+    # CPIO archive, and zstd compresses raw ELF binaries better than UPX-packed
+    # ones (UPX output looks like random data to zstd, defeating its compression).
     _log.log("All tools ready.")