hashicorp/nomad · warning

failed to find %s: %v

Error message

failed to find %s: %v

What it means

The BridgeFingerprint's findDir checks for the existence of /sys/module/<name> to detect whether the bridge kernel module is loaded/built-in. This error means os.Stat on that sysfs directory failed (typically ENOENT). It is one of several accumulated errors from detect(); a non-nil result just disables the bridge network mode fingerprint (resp.Detected=false), it does not fail the client.

Source

Thrown at client/fingerprint/bridge_linux.go:102

		errs = multierror.Append(errs, err)
	} else {
		return nil
	}

	// check if the module is dynamic but unloaded (will have a dep entry)
	dependsPath := fmt.Sprintf("/lib/modules/%s/modules.dep", hostInfo.KernelVersion)
	if err := f.searchFile(module, dependsPath, f.regexp(dependsModuleRe, module)); err != nil {
		errs = multierror.Append(errs, err)
	} else {
		return nil
	}

	return errs
}

func (f *BridgeFingerprint) findDir(dirname string) error {
	if _, err := os.Stat(dirname); err != nil {
		return fmt.Errorf("failed to find %s: %v", dirname, err)
	} else {
		return nil
	}
}

func (f *BridgeFingerprint) searchFile(module, filename string, re *regexp.Regexp) error {
	file, err := os.Open(filename)
	if err != nil {
		return fmt.Errorf("failed to open %s: %v", filename, err)
	}
	defer func() {
		_ = file.Close()
	}()

	scanner := bufio.NewScanner(file)
	for scanner.Scan() {
		if re.MatchString(scanner.Text()) {
			return nil // found the module!

View on GitHub (pinned to 482b49bf1a)

Solutions

1. Load the module on the host: run 'modprobe bridge' and ensure it persists across reboots (e.g. /etc/modules-load.d/bridge.conf).
2. Verify the host kernel has bridge support: check 'ls /sys/module/bridge' and 'grep bridge /proc/modules'.
3. If running Nomad inside a container, run it on the host or mount /sys so module info is visible.
4. If bridge networking is not needed, ignore this - the fingerprint simply marks the node as not supporting bridge mode.

Example fix

# before (module missing)
$ ls /sys/module/bridge
ls: cannot access '/sys/module/bridge': No such file or directory
# after
$ sudo modprobe bridge && echo bridge | sudo tee /etc/modules-load.d/bridge.conf
$ ls /sys/module/bridge
parameters  refcnt  uevent

// host-side preflight (shell)
// test -d /sys/module/bridge || echo 'bridge module not loaded; run: modprobe bridge'

if err := f.detect(bridgeKernelModuleName); err != nil {
    // library already does this: log and disable bridge mode rather than failing
    f.logger.Warn("bridge network mode disabled", "error", err)
    return nil // resp.Detected stays false
}

When it happens

Trigger: detect('bridge') calls findDir("/sys/module/bridge") and the directory does not exist - the bridge module is neither loaded nor built into the running kernel, or the host lacks the /sys/module entry.

Common situations: Minimal/containerized hosts (e.g. running Nomad in a container with a restricted /sys) where the module dir is not visible; kernel built without bridge support (e.g. some VM appliances); module available but not yet loaded and not present in modules.dep.

Related errors

• module %s not in %s
• failed to open %s: %v
• failed to scan %s: %v
• fingerprint name cannot be empty
• empty response from AWS metadata

AI-assisted analysis of hashicorp/nomad@482b49bf1a (2026-09-04). Data as JSON: /api/errors/9e1a4ec9fc0025d2. Report an issue: GitHub.