juanfont/headscale · error

saving netmap to /tmp/control: %w

Error message

saving netmap to /tmp/control: %w

What it means

Error "saving netmap to /tmp/control: %w" thrown in juanfont/headscale.

Source

Thrown at integration/tsic/tsic.go:1055

	command := []string{
		tailscaleBin,
		"debug",
		"netmap",
	}

	nm, raw, err := execJSON[netmap.NetworkMap](
		t,
		command,
		"executing tailscale debug netmap command",
		"unmarshalling tailscale netmap",
	)
	if err != nil {
		return nil, err
	}

	err = os.WriteFile(fmt.Sprintf("/tmp/control/%s_netmap.json", t.hostname), []byte(raw), 0o755) //nolint:gosec // test infrastructure log files
	if err != nil {
		return nil, fmt.Errorf("saving netmap to /tmp/control: %w", err)
	}

	return nm, nil
}

// Netmap returns the current Netmap ([netmap.NetworkMap]) of the Tailscale instance.
// This implementation is based on getting the netmap from `tailscale debug watch-ipn`
// as there seem to be some weirdness omitting endpoint and DERP info if we use
// Patch updates.
// This implementation works on all supported versions.
// func (t *TailscaleInContainer) Netmap() (*netmap.NetworkMap, error) {
// 	// watch-ipn will only give an update if something is happening,
// 	// since we send keep alives, the worst case for this should be
// 	// 1 minute, but set a slightly more conservative time.
// 	ctx, _ := context.WithTimeout(context.Background(), 3*time.Minute)

// 	notify, err := t.watchIPN(ctx)
// 	if err != nil {

View on GitHub (pinned to 565fd254d0)

Solutions

1. Inspect the wrapped error for the underlying cause and correct the failing condition (saving netmap to /tmp/control); retry the operation after fixing the input, configuration, or environment.

Example fix

Inspect the wrapped error for the underlying cause and correct the failing condition (saving netmap to /tmp/control); retry the operation after fixing the input, configuration, or environment.

When it happens

Trigger: Thrown at integration/tsic/tsic.go:1055 when the library encounters an invalid state.

Common situations: Saving the netmap to /tmp/control failed. Check the debug collection directory is writable in the test environment.

AI-assisted analysis of juanfont/headscale@565fd254d0 (2026-08-15). Data as JSON: /api/errors/a85ed5c17cc1e01e. Report an issue: GitHub.