[Bug] Different behavior depending on override_local_dns definition

[aalewis]

Is this a support request?

• This is not a support request

Is there an existing issue for this?

• I have searched the existing issues

Current Behavior

Headscale 0.27.1, tailscale 1.90.6

relevant config:
dns:
  magic_dns: true
  base_domain: myexample.com
  override_local_dns: yes
  nameservers:
    global:
      - 8.8.8.8
      - 1.1.1.1

With this setup, tailscale client reports:

Resolvers (in preference order):
  (no resolvers configured, system default will be used: see 'System DNS configuration' below)

Changing override_local_dns to "no":

Resolvers (in preference order):
  (no resolvers configured, system default will be used: see 'System DNS configuration' below)

Commenting out override_local_dns results in:

  - 8.8.8.8
  - 1.1.1.1

There are now three outcomes around the override_local_dns config variable, seems like? Yes/No/Undefined.

Expected Behavior

I expect variables to have a default value, not to have different behavior if undefined.

Steps To Reproduce

See above for outcomes.

Environment

- OS: Debian Trixie
- Headscale version: 0.27.1 non-container
- Tailscale version: 1.90.6

Runtime environment

• Headscale is behind a (reverse) proxy
• Headscale runs in a container

Debug information

n/a