Moved to position 7 — after core utils, which give it curl, and well before SSH
hardening, which is the step that can lock you out. The argument is that
Tailscale is a second way into the machine, so it wants to exist before anything
that can go wrong does.
── Why the original hung, and what stops it now ──
Its prompt accepted an empty auth key and passed it anyway. `tailscale up
--authkey ""` falls back to the interactive flow: it prints a URL and blocks,
with no timeout, forever. From the outside that is a script that has frozen.
Nothing here passes an empty key — the flag is omitted entirely, and the run says
in advance that a URL is coming and that it will wait. Every call carries
--timeout=60s, and a timeout is reported with the command to run by hand rather
than left as silence. State is read with `tailscale status --json` before
anything is run, so a node that is already up is offered a reconfigure instead of
having `up` fired at it blindly.
Diagnosed on this host rather than guessed at, and honestly the diagnosis is
partial: the exit-node branch left no trace at all — no /etc/sysctl.d file,
networkd-dispatcher present but with zero mentions in apt history, so it came
with the image. ip_forward=1 came from the unconditional part of the section, not
the branch. That points at `tailscale up` as where it stopped, and the empty-key
path is the candidate that fits, but I could not reproduce it to be certain.
── What the section now covers ──
control plane Tailscale's own service by default; a self-hosted headscale as
an explicit choice with NO suggested URL. The original defaulted
to headscale.pastilhas.eu, so a stranger running it pointed
their machine at somebody else's control plane.
auth key, or the browser flow, stated as an equal option
Tailscale SSH ssh over the tailnet with no keys, governed by tailnet ACLs —
and pointed out as a way back in if the sshd hardening later in
the run goes wrong
subnet router homelab only, defaulting to this machine's actual LAN CIDR
exit node with what it means for whose traffic goes where
forwarding sysctls and Tailscale's recommended NIC offload settings, and
only when an exit node or a route actually needs them
Approval is mentioned: an advertised route or exit node does nothing until it is
approved in the admin console, which is otherwise a silent non-event.
Also added --only <step> and --list, because this section in particular needs to
be run on its own while it is being worked on. A step run that way ignores the
progress file and does not record itself — asking for one step is not progress
through the script.
One bash quirk fixed on the way: "${VAR:-Tailscale's own service}" does not
parse. An apostrophe inside a ${:-} default opens a quoted section that swallows
the closing brace, and the error surfaces as "unexpected EOF" 400 lines away.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
