tailscaled does not reliably enable IPv6 forwarding inside a container
network namespace ('IPv6 forwarding is disabled'), so advertised IPv6
subnet routes silently fail. Add a tiny entrypoint.sh that sets
net.ipv4.ip_forward and net.ipv6.conf.all.forwarding (writable inside a
RouterOS container netns), then exec's tailscaled. Built in the builder
stage so it stays in the single /usr/local/bin COPY layer.
Verified: privileged run flips v6 forwarding 0->1 and exec's tailscaled
with CMD args intact.
Without ipnbus, 'tailscale up' fires config at the daemon and returns
immediately ('built with ts_omit_ipnbus; not waiting for completion')
without printing the auth URL or confirming success. Add it to the
allowlist so interactive 'up' behaves normally.
The --extra-small baseline omits unixsocketidentity, but without it the
localapi cannot verify a request came over the trusted unix socket, so
PermitRead/PermitWrite are always false and every CLI call (status, up,
set, ...) returns 'access denied' (tailscale/tailscale#17873). Add it to
the opt-in allowlist. Negligible size cost (~3.55 MB unchanged); the CLI
is non-functional without it.
cachenetmap only persists the netmap to disk for cold-start-during-
control-outage; the in-memory map (the common case) is unaffected. Its
cost is a flash write on every netmap delta, which is frequent on active
tailnets — the opposite of this image's flash-conservation goal. Remove
it from the allowlist. Also expand the clientupdate/cachenetmap comments
to document why they're deliberately omitted, and fix the stale volume/
statedir comments that referenced the now-removed on-disk netmap cache.
Creating the tailscale argv[0] symlinks with RUN in the final scratch
stage forced overlayfs to copy-up the whole /usr/local/bin directory,
duplicating the ~3 MB binary into a second layer. RouterOS extracts
overlay layers separately, so the on-disk rootfs measured ~7 MB instead
of ~3.4 MB. Assemble /usr/local/bin in the builder stage and bring it in
with a single COPY layer. Verified on RouterOS 7.21.2: du -sx / now ~3.4 MB.
Lumpiasty
Renovate Bot