The Tailscale daemon only refreshed TLS certs as a side effect of inbound
TLS handshakes or "tailscale cert" CLI calls. A node that doesn't see
inbound traffic during the renewal window silently rolls past expiry.
Add a once-per-hour background loop on LocalBackend that enumerates Serve
and Funnel HTTPS hostnames (filtered against the netmap's CertDomains so
we don't poke ACME for other nodes' service hostnames) and calls the
existing GetCertPEM path. The renewal decision (ARI window, then 2/3
expiry fallback) is unchanged; the loop just guarantees it runs.
For visibility during initial issuance or restart with a long-expired
cached cert, add a "tls-cert-pending" health Warnable that's set while
ACME is in flight and no usable cached cert exists. Async renewal of a
still-valid cert intentionally doesn't fire it. And then make the CLI "cert"
subcommand print out a warning if it's blocking due to a cert fetch
in flight, using that health info.
Fixes#19911Fixes#19912
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Change-Id: I144e46c40e957b2e879587decace32a523a6eade