kubernetes/kops · error

unknown option: %q

Error message

unknown option: %q

What it means

BindMount.execute parses the mount Options list into categories (simple, remount, make-shared options). An option it does not recognize (not a mount flag like exec/noexec/suid/nosuid/dev/nodev, not ro/rw/shared etc.) causes this error. It is a programming/config validation error preventing the mount from being performed.

Source

Thrown at upup/pkg/fi/nodeup/nodetasks/bindmount.go:207

}

func (e *BindMount) execute(t Executor) error {
	var simpleOptions []string
	var makeOptions []string
	var remountOptions []string
	for _, option := range e.Options {
		switch option {
		case "ro":
			simpleOptions = append(simpleOptions, option)

		case "rshared":
			makeOptions = append(makeOptions, "--make-rshared")

		case "exec", "noexec", "suid", "nosuid", "dev", "nodev":
			remountOptions = append(remountOptions, option)

		default:
			return fmt.Errorf("unknown option: %q", option)
		}
	}

	{
		args := []string{"mount"}
		if e.Recursive {
			args = append(args, "--rbind")
		} else {
			args = append(args, "--bind")
		}
		if len(simpleOptions) != 0 {
			args = append(args, "-o", strings.Join(simpleOptions, ","))
		}
		args = append(args, e.Source, e.Mountpoint)

		klog.Infof("running mount command %s", args)
		if output, err := t.CombinedOutput(args); err != nil {
			return fmt.Errorf("error doing mount %q: %v: %s", strings.Join(args, " "), err, string(output))

View on GitHub (pinned to 4c8573c808)

Solutions

1. Remove or correct the unsupported option in the BindMount task's Options list
2. Only use options known to the switch: ro/rw, shared/rshared/private/rprivate/slave/rslave, exec/noexec, suid/nosuid, dev/nodev, --make-rshared
3. Update kOps to a version supporting the desired option, or extend bindmount.go's switch
4. Check which option value triggered it — the %q in the error names the exact culprit

Example fix

// before
e.Options = []string{"rw", "relatime"}
// returns "unknown option: \"relatime\""
// after
e.Options = []string{"rw"} // only handled options

var known = map[string]bool{
  "ro": true, "rw": true, "shared": true, "rshared": true, "private": true,
  "rprivate": true, "slave": true, "rslave": true, "exec": true, "noexec": true,
  "suid": true, "nosuid": true, "dev": true, "nodev": true,
}
for _, o := range opts {
  if !known[o] { return fmt.Errorf("unsupported bindmount option %q", o) }
}

if err := nodeup.Run(ctx); err != nil {
  if strings.Contains(err.Error(), "unknown option") {
    // message names the offending option via %q — fix the task config
  }
}

When it happens

Trigger: A BindMount task is created with an option string outside the known switch cases — e.g. a typo like "recatime" instead of "relatime" or a kernel-specific flag the task does not handle.

Common situations: Custom model code or patched kOps adding new mount options; typo in instance-group/mount configuration; upstream adding kernel options not yet handled by bindmount.go.

Related errors

• failed to create bpf mount unit: %w
• failed to create cgroupv2 mount unit: %w
• failed to ensure the directory: %s, error: %w
• failed to check if device %q is mounted, error: %w
• challenge not set

AI-assisted analysis of kubernetes/kops@4c8573c808 (2026-09-05). Data as JSON: /api/errors/34c3add9f87fc541. Report an issue: GitHub.