thanos-io/thanos · error

open dir

Error message

open dir

What it means

This error wraps a failure from s.dir.Open(".") inside blockMetasFromOldest, which opens the shipper's local directory to enumerate block directories. The shipper dir is an afero Fs abstraction over the TSDB dir; if it cannot be opened, no block metas can be listed and Sync/AreAllBlocksUploaded fail.

Solutions

1. Verify the shipper/TSDB directory path exists and is readable: ls -ld <dir>; fix the configured path if wrong.
2. Fix permissions so the process can open the directory (chown/chmod).
3. Check the volume is mounted (df -h, mount output); remount if detached.
4. Restart the process after restoring the directory so afero's dir handle is re-established.

Example fix

// before: wrong path configured
--prometheus.tsdb.path=/prometheus/data/typo

// after: point to the actual TSDB dir
--prometheus.tsdb.path=/prometheus

info, err := os.Stat(shipperDir)
if os.IsNotExist(err) {
    return fmt.Errorf("shipper dir %s does not exist", shipperDir)
}
if err != nil {
    return err
}
if !info.IsDir() {
    return fmt.Errorf("%s is not a directory", shipperDir)
}

func dirExistsAndReadable(path string) bool {
    info, err := os.Stat(path)
    return err == nil && info.IsDir()
}

dir, err := s.dir.Open(".")
if err != nil {
    if os.IsNotExist(err) {
        return nil, nil, errors.Wrapf(err, "open dir: shipper dir missing, check configured path")
    }
    return nil, nil, errors.Wrap(err, "open dir")
}

When it happens

Trigger: Calling Shipper.Sync or AreAllBlocksUploaded when the configured shipper directory no longer exists (deleted/renamed), is not accessible due to permissions, or the underlying filesystem is unavailable/unmounted.

Common situations: Misconfigured --prometheus.tsdb.path / shipper dir path pointing to a non-existent location; NFS or cloud volume detach; directory removed by aggressive retention cleanup while the sidecar was running.

Understand the failure class

Background: "open() failed", "failed to open file", "cannot create file" — what a file open error means and how to fix it — this error's family across 42 libraries.

Related errors

• read dir
• remove any existing index at path
• hard link block
• write meta file
• stat block

AI-assisted analysis of thanos-io/thanos@35b8b99117 (2026-09-07). Data as JSON: /api/errors/92ef69f429608a64. Report an issue: GitHub.

Appendix: source

Thrown at pkg/shipper/shipper.go:527

	meta.Thanos.Source = s.source
	meta.Thanos.SegmentFiles = block.GetSegmentFiles(absUpdir)
	if err := meta.WriteToDir(s.logger, absUpdir); err != nil {
		return errors.Wrap(err, "write meta file")
	}
	var uploadOptions []objstore.UploadOption
	if s.uploadConcurrency > 0 {
		uploadOptions = append(uploadOptions, objstore.WithUploadConcurrency(s.uploadConcurrency))
	}
	return block.Upload(ctx, s.logger, s.bucket, absUpdir, s.hashFunc, uploadOptions...)
}

// blockMetasFromOldest returns the block meta of each block found in dir
// sorted by minTime asc.
func (s *Shipper) blockMetasFromOldest() (metas []*metadata.Meta, failedBlocks []string, _ error) {

	dir, err := s.dir.Open(".")
	if err != nil {
		return nil, nil, errors.Wrap(err, "open dir")
	}
	defer runutil.CloseWithLogOnErr(s.logger, dir, "shipper dir")

	fis, err := dir.ReadDir(-1)
	if err != nil {
		return nil, nil, errors.Wrap(err, "read dir")
	}

	names := make([]string, 0, len(fis))
	for _, fi := range fis {
		names = append(names, fi.Name())
	}
	for _, n := range names {
		if _, ok := block.IsBlockDir(n); !ok {
			continue
		}
		dir := filepath.Join(s.dir.Name(), n)

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