What is the issue?

When I tried to use the TS_SERVE_CONFIG environment variable (documentation referenced below) to set a serve config when deploying Tailscale in K3s (Kubernetes), the serve config was not being set (as observed by tailscale serve status --json and inspecting tailscaled.state file, and serve itself not working). No error message is being displayed either. After investigating, I believe I found the offending code with a relevant TODO item, referenced below.

Tailscale currently fails to start if the file referenced by TS_SERVE_CONFIG is missing or malformed, but not when it is being ignored. I think at the very least, Tailscale should show an error message or even fail to start, if this issue is more complicated than simply removing the if statement.

For anyone wondering, the current workaround is to use cat config.json | tailscale serve set-raw, but set-raw is an undocumented feature that might be gone anytime.

In any case, thank you very much for this software! Tailscale is really convenient to use and I am willing to hack around it if it means that I can avoid other less convenient alternatives.

References:

• https://tailscale.com/kb/1282/docker#ts_serve_config

• tailscale/cmd/containerboot/serve.go

  Lines 92 to 96 in c43c5ca

  	// TODO(irbekrm): This means that serve config that does not expose HTTPS endpoint will not be set for a tailnet
  	// that does not have HTTPS enabled. We probably want to fix this.
  	if certDomain == kubetypes.ValueNoHTTPS {
  	return nil
  	}

Steps to reproduce

No response

Are there any recent changes that introduced the issue?

No response

OS

No response

OS version

No response

Tailscale version

1.78.3

Other software

No response

Bug report

No response