What causes "Unable to get fileinfo for %s: %s" in hashicorp/packer?

Re-run the build; this is frequently a race with file deletion

Unable to get fileinfo for %s: %s

Error message

Unable to get fileinfo for %s: %s

What it means

createTarArchive opened an artifact file but file.Stat() failed, so tar header creation cannot proceed. The post-processor needs the file's size/mode/timestamps to build a tar header; without stat metadata it aborts and PostProcess reports 'Error creating tar'.

Source

Thrown at post-processor/compress/post-processor.go:390

	}
	_ = gzipWriter.SetConcurrency(500000, runtime.GOMAXPROCS(-1))
	return gzipWriter, nil
}

func createTarArchive(files []string, output io.WriteCloser) error {
	archive := tar.NewWriter(output)
	defer archive.Close()

	for _, path := range files {
		file, err := os.Open(path)
		if err != nil {
			return fmt.Errorf("Unable to read file %s: %s", path, err)
		}
		defer file.Close()

		fi, err := file.Stat()
		if err != nil {
			return fmt.Errorf("Unable to get fileinfo for %s: %s", path, err)
		}

		header, err := tar.FileInfoHeader(fi, path)
		if err != nil {
			return fmt.Errorf("Failed to create tar header for %s: %s", path, err)
		}

		// workaround for archive format on go >=1.10
		setHeaderFormat(header)

		if err := archive.WriteHeader(header); err != nil {
			return fmt.Errorf("Failed to write tar header for %s: %s", path, err)
		}

		if _, err := io.Copy(archive, file); err != nil {
			return fmt.Errorf("Failed to copy %s data to archive: %s", path, err)
		}
	}

View on GitHub (pinned to eb36e3c3e4)

Solutions

Re-run the build; this is frequently a race with file deletion
Check the filesystem backing the artifact (dmesg / mount health) for I/O errors
Avoid external cleanup processes touching the output directory during the build
Use a local output directory instead of a network mount

Defensive patterns

Strategy: retry

Validate before calling

// pre-flight: confirm stat works on all artifact files (detects flaky mounts)
for _, p := range artifact.Files() {
    if _, err := os.Stat(p); err != nil {
        return fmt.Errorf("stat unavailable for %s: %w", p, err)
    }
}

Try / catch

// Go: stat races are transient; retry the post-process once
artifact, _, _, err := pp.PostProcess(ctx, ui, artifact)
if err != nil && strings.Contains(err.Error(), "Unable to get fileinfo") {
    time.Sleep(time.Second)
    return pp.PostProcess(ctx, ui, artifact)
}

Prevention

Prefer local filesystems over NFS/SMB for build outputs
Stop external cleanup jobs that touch output directories during builds
Check filesystem health (dmesg) if stat errors recur
Re-run the pipeline when errors are sporadic

When it happens

Trigger: createTarArchive calls file.Stat() on a successfully opened file and the OS returns an error — rare, usually indicating the file was deleted between Open and Stat, or an underlying filesystem I/O error.

Common situations: Files on flaky network mounts (NFS/SMB) whose metadata lookups fail; concurrent cleanup jobs removing artifacts during packaging; exotic filesystems with unreliable stat support.

Related errors

AI-assisted analysis of hashicorp/packer@eb36e3c3e4 (2026-09-05). Data as JSON: /api/errors/b5646d5c12cfacb5. Report an issue: GitHub.