kubernetes/kops · error

unable to remap asset: %w

Error message

unable to remap asset: %w

What it means

After URL parsing and optional hash parsing, buildFileAsset calls assetBuilder.RemapFile to resolve the asset to its final location/hash (mirrors, vendored copies). A failure there is wrapped with this message. It means the containerd-family asset could not be resolved into a concrete FileAsset for provisioning.

Source

Thrown at pkg/nodemodel/wellknownassets/containerd.go:112

func buildFileAsset(assetBuilder *assets.AssetBuilder, canonicalURL string, knownHashString string) (*assets.FileAsset, error) {
	u, err := url.Parse(canonicalURL)
	if err != nil {
		return nil, fmt.Errorf("unable to parse asset URL %q: %w", canonicalURL, err)
	}

	var knownHash *hashing.Hash
	if knownHashString != "" {
		h, err := hashing.FromString(knownHashString)
		if err != nil {
			return nil, fmt.Errorf("unable to parse asset hash %q: %w", knownHashString, err)
		}
		knownHash = h
	}

	asset, err := assetBuilder.RemapFile(u, knownHash)
	if err != nil {
		return nil, fmt.Errorf("unable to remap asset: %w", err)
	}

	return asset, nil
}

View on GitHub (pinned to 4c8573c808)

Solutions

1. Read the wrapped cause: network errors → retry after restoring connectivity; hash mismatch → confirm the expected hash matches the mirror's copy
2. Ensure the configured asset mirror actually hosts the exact containerd/nerdctl/runc release being requested
3. Remove custom mirror overrides to fall back to upstream GitHub release URLs
4. Re-run kops once network access to the asset host is confirmed

// verify the asset host resolves and serves the release before remapping
if resp, err := http.Head(canonicalURL); err != nil || resp.StatusCode >= 400 {
    return fmt.Errorf("asset host not ready for %s: status=%d err=%v", canonicalURL, resp.StatusCode, err)
}

asset, err := wellknownassets.FindContainerdAsset(ig, assetBuilder, arch)
var remapErr *fmt.Errorf
if err != nil && errors.As(err, &remapErr) && strings.Contains(err.Error(), "unable to remap asset") {
    // transient network/mirror failure: retry with backoff, then surface wrapped cause
    return retryWithBackoff(3, func() error { _, err = wellknownassets.FindContainerdAsset(ig, assetBuilder, arch); return err })
}

When it happens

Trigger: FindContainerdAsset, FindNerdctlAsset, or FindRuncAsset supply a valid URL but assetBuilder.RemapFile errors — typically mirror unavailability, network failure while hashing the remote asset, or a hash mismatch with the remapped copy.

Common situations: Corporate proxy/firewall blocking GitHub release downloads during kops create; asset mirror not synced with the requested containerd/nerdctl/runc release; transient 5xx from the download host during offline-ish CI builds.

Related errors

• unable to find any containerd binaries in assets
• error finding contained version
• error parsing container runtime version %q: %w
• error building containerd flags: %v
• building json: %w

AI-assisted analysis of kubernetes/kops@4c8573c808 (2026-09-05). Data as JSON: /api/errors/5e216bd5fb1d9f24. Report an issue: GitHub.