containerd/containerd · error

failed to get info from content store: %w

Error message

failed to get info from content store: %w

What it means

This error is returned by the EROFS differ's Compare method when the underlying containerd content store lookup fails. After opening the layer blob, Compare calls s.store.Info(ctx, dgst) to fetch metadata for the diff's digest; any error from the content store (blob missing, backend failure, cancelled context) is wrapped with this message and Compare returns an empty descriptor.

Source

Thrown at plugins/diff/erofs/compare_linux.go:172

		}
	}

	var commitopts []content.Opt
	if config.Labels != nil {
		commitopts = append(commitopts, content.WithLabels(config.Labels))
	}

	dgst := cw.Digest()
	if errOpen = cw.Commit(ctx, 0, dgst, commitopts...); errOpen != nil {
		if !errdefs.IsAlreadyExists(errOpen) {
			return emptyDesc, fmt.Errorf("failed to commit: %w", errOpen)
		}
		errOpen = nil
	}

	info, err := s.store.Info(ctx, dgst)
	if err != nil {
		return emptyDesc, fmt.Errorf("failed to get info from content store: %w", err)
	}
	if info.Labels == nil {
		info.Labels = make(map[string]string)
	}
	// Set "containerd.io/uncompressed" label if digest already existed without label
	if _, ok := info.Labels[labels.LabelUncompressed]; !ok {
		info.Labels[labels.LabelUncompressed] = config.Labels[labels.LabelUncompressed]
		if _, err := s.store.Update(ctx, info, "labels."+labels.LabelUncompressed); err != nil {
			return emptyDesc, fmt.Errorf("error setting uncompressed label: %w", err)
		}
	}

	return ocispec.Descriptor{
		MediaType: config.MediaType,
		Size:      info.Size,
		Digest:    info.Digest,
	}, nil
}

View on GitHub (pinned to 4246446a2b)

Solutions

1. Verify the blob exists in the content store: `ctr -n <namespace> content ls` or `ctr content get <dgst>`; re-pull the image if it is missing.
2. Check that the Compare call runs in the same namespace as the store that holds the blob.
3. Check content store backend health (bolt DB file, disk space, permissions) and inspect daemon logs for the underlying wrapped error.
4. If blobs are being evicted, raise GC limits or re-pull the image before calling Compare.

Example fix

// before: assuming the layer blob is local
meta, err := differ.Compare(ctx, layerDesc, mounts, opts...)
// after: ensure the blob is present before comparing
if _, err := client.ContentStore().Info(ctx, layerDesc.Digest); err != nil {
    if err := client.Fetch(ctx, container, layerDesc); err != nil { return err }
}
meta, err := differ.Compare(ctx, layerDesc, mounts, opts...)

cs := client.ContentStore()
if _, err := cs.Info(ctx, desc.Digest); err != nil {
    // blob missing locally; fetch it before calling Compare
    if err := client.Fetch(ctx, container, desc); err != nil { return fmt.Errorf("blob %s unavailable: %w", desc.Digest, err) }
}

func blobInStore(ctx context.Context, cs contentstore.ContentStore, dgst digest.Digest) bool {
    _, err := cs.Info(ctx, dgst)
    return err == nil
}

desc, err := differ.Compare(ctx, layerDesc, mounts, opts...)
if err != nil && strings.Contains(err.Error(), "failed to get info from content store") {
    // re-pull the image / restore the blob, then retry once
    if rerr := repull(ctx, ref); rerr == nil { desc, err = differ.Compare(ctx, layerDesc, mounts, opts...) }
}

When it happens

Trigger: Calling Compare (via the diff service or on snapshot commit) with a digest that is not present in the local content store; a content store backend (e.g. bolt metadata or blob store) I/O failure; ctx cancelled before Info completes; a garbage-collected blob whose digest is still referenced.

Common situations: Layers pruned by automatic GC before the diff is computed; pulling with content disabled or partial (lazy/remote) content so the blob was never materialized locally; corrupted content store DB after an unclean shutdown; referencing a digest from a different containerd namespace than the one the store is opened with.

Related errors

• failed to get reader: %w
• error setting uncompressed label: %w
• unsupported media type: %s
• failed to open writer: %w
• writer has been reset

AI-assisted analysis of containerd/containerd@4246446a2b (2026-09-02). Data as JSON: /api/errors/2c421b4352eabd92. Report an issue: GitHub.