== 🩹 Micropatch server — future sketch (NOT built)

____
*Status: sketch / placeholder.* This is a deliberate "`here’s where it
could go`" note, not a deliverable. It is parked here precisely because
the *Pi 2B is too small to host it* (1 GB RAM, slow SD, 100 Mbit USB-bus
NIC). It wants a Pi 4 / 5 or an x86 mini-PC — see `+PI4-AND-BEYOND.md+`.
____

=== The idea

A small, LAN-local service that turns the outpost from a passive
sinkhole into an *active patch distribution point*: your devices and
containers pull *pinned, vetted, mirrored* updates _from the outpost_
rather than reaching out to the wider internet individually. "`Micro`"
because the ambition is tiny and sharply scoped — not a full
Spacewalk/Foreman, just enough to:

[arabic]
. *Mirror* a small set of upstreams you actually use (Alpine `+apk+`
repos, selected container image digests, maybe firmware blobs).
. *Pin + sign* what it mirrors, so every LAN device gets a reproducible,
tamper-evident artifact (ties naturally into the digest-pinning this
repo already does for AdGuard).
. *Serve* them on the LAN over plain HTTP(S) + mDNS discovery, the same
shape as the print server.

=== Why it pairs well with a sinkhole

The outpost already sees and shapes the LAN’s DNS. A micropatch server
is the logical "`supply side`" twin: the sinkhole says _what you may
reach_; the micropatch server provides _vetted copies of the things you
should reach_. Same box, same "`quiet trusted infrastructure`" role,
same reproducibility discipline.

=== Rough shape (when the hardware exists)

....
[ upstream apk / OCI registries ]
            |  (scheduled, signed pull)
            v
   micropatch-server (Pi 4+ / x86)
   ├── mirror store (content-addressed, digest-pinned)
   ├── signer (your existing GPG/SSH signing identity)
   └── LAN endpoints: apk repo + OCI pull-through cache + mDNS advert
            |
            v
[ LAN devices + the outpost's own containers pull from here ]
....

=== Why NOT on the 2B

* A pull-through OCI cache + apk mirror is disk- and RAM-hungry; the 2B
has neither to spare.
* 100 Mbit on a shared USB 2.0 bus makes it a poor distribution point.
* SD-card wear from a write-heavy mirror is a real failure mode.

=== Open questions (for future-you)

* Mirror vs pull-through cache vs both?
* Reuse the estate signing identity, or a box-local key?
* Where does verification live — verify-on-ingest, verify-on-serve, or
both?
* Does this subsume / overlap an existing estate component? (Check
before building.)