kubernetes/kops · error

error expanding asset file %q %v: %s

Error message

error expanding asset file %q %v: %s

What it means

After creating a temp dir, addArchive runs 'tar zxf <archiveFile> -C <extractedTemp>'. If tar exits nonzero (it also captures stderr via CombinedOutput), the asset store fails with 'error expanding asset file %q %v: %s' including the tar output so the developer can see why extraction failed.

Source

Thrown at upup/pkg/fi/assetstore.go:315

func (a *AssetStore) addArchive(archiveSource *Source, archiveFile string) error {
	extracted := path.Join(a.cacheDir, "extracted/"+path.Base(archiveFile))

	if _, err := os.Stat(extracted); os.IsNotExist(err) {
		// We extract to a temporary dir which we then rename so this is atomic
		// (untarring can be slow, and we might crash / be interrupted half-way through)
		extractedTemp := extracted + ".tmp-" + strconv.FormatInt(time.Now().UnixNano(), 10)
		err := os.MkdirAll(extractedTemp, 0o755)
		if err != nil {
			return fmt.Errorf("error creating directories %q: %v", path.Dir(extractedTemp), err)
		}

		args := []string{"tar", "zxf", archiveFile, "-C", extractedTemp}
		klog.Infof("running extract command %s", args)
		cmd := exec.Command(args[0], args[1:]...)
		output, err := cmd.CombinedOutput()
		if err != nil {
			return fmt.Errorf("error expanding asset file %q %v: %s", archiveFile, err, string(output))
		}

		if err := os.Rename(extractedTemp, extracted); err != nil {
			return fmt.Errorf("error renaming extracted temp dir %s -> %s: %v", extractedTemp, extracted, err)
		}
	}

	localBase := extracted
	assetBase := ""

	walker := func(localPath string, info os.FileInfo, err error) error {
		if err != nil {
			return fmt.Errorf("error descending into path %q: %v", localPath, err)
		}

		if info.IsDir() {
			return nil
		}

View on GitHub (pinned to 4c8573c808)

Solutions

1. Read the trailing %s field of the error — it contains tar's CombinedOutput with the exact failure.
2. Verify the archive integrity (tar -tzf <file>, sha256 vs upstream checksum).
3. Re-download the asset after clearing caches/proxies that may serve corrupt bodies.
4. Ensure the file is actually a gzipped tarball (not zip or plain binary) and matches the expected version.
5. If tar is failing on permissions/paths shown in output, fix those before retrying.

Example fix

// verify archive manually before running the kOps operation
$ file nodeup.tar.gz            # expect: gzip compressed data
$ tar -tzf nodeup.tar.gz        # must list entries without error
$ sha256sum nodeup.tar.gz       # compare with published checksum

import { execSync } from "child_process" // verify archive before handing to kOps
execSync(`tar -tzf ${archiveFile}`, { stdio: "ignore" }) // throws if not a valid gzip/tar
execSync(`sha256sum -c ${archiveFile}.sha256`) // checksum check

function looksLikeGzip(buf: Buffer): boolean { return buf.length > 2 && buf[0] === 0x1f && buf[1] === 0x8b }

try {
  await addURLs(urls)
} catch (e) {
  if (/error expanding asset file/.test(e.message)) {
    console.error("tar failed; output:", e.message) // error text embeds tar's CombinedOutput
    // re-download and verify checksum before retrying
  }
  throw e
}

When it happens

Trigger: addURLs -> addArchive where the downloaded file is not a valid gzip/tar archive, is truncated/corrupt, is empty, or the tar binary is missing/fails for any reason.

Common situations: Corrupted download from a mirror or proxy injecting HTML error pages into the tarball; truncated download on flaky network; wrong file uploaded to the asset location; checksum mismatch not detected upstream.

Related errors

• unable to marshal YAML: %v
• unable to marshal JSON: %v
• unable to find any containerd binaries in assets
• error finding runc asset
• unable to locate asset %q

AI-assisted analysis of kubernetes/kops@4c8573c808 (2026-09-05). Data as JSON: /api/errors/ac97b85d9d1cf4a7. Report an issue: GitHub.