A machine's uplink is a seat (hq ADR 0117)

the-uplink joins the closed set as a node seat delivering nothing. Its
holder is the module for the machine's own network manager, and keeps
that manager from contradicting the mesh — the resolver file left to
resolv-conf, mesh0 left alone — without ever declaring a link. Held
per machine, so a machine running two managers is refused at
assignment rather than found by its resolver being rewritten. The
count test moves to fifteen; one test holds the seat's shape.

internal/catalogue/seats.go

@@ -47,6 +47,13 @@ var seats = []Seat{
 	{Name: "the-private-network", Scope: ScopeNode, Decision: "novox/hq ADR 0110"},
 	{Name: "the-resolver-configuration", Scope: ScopeNode, Decision: "novox/hq ADR 0110"},
 	{Name: "the-showcase", Scope: ScopeNode, Decision: "novox/hq ADR 0110"},
+	// The program that manages the machine's own network. It delivers nothing: its holder only
+	// keeps the manager and the mesh from contradicting each other — the resolver file left to the
+	// mesh, the private network's interface left alone — and never declares a link, an address or
+	// a wireless network, because the link is the only channel a fix could arrive on. A seat
+	// rather than a condition in the resolver's module, so a machine running two managers is
+	// refused at assignment instead of found by the resolver being rewritten (novox/hq ADR 0117).
+	{Name: "the-uplink", Scope: ScopeNode, Decision: "novox/hq ADR 0117"},
 }
 
 // Seats is every seat the mesh defines, in reading order.

internal/catalogue/seats_test.go

@@ -44,12 +44,32 @@ func TestTheSeatsAreAClosedSetAndEachNamesItsDecision(t *testing.T) {
 			delivered[s.Delivers] = s.Name
 		}
 	}
-	if len(Seats()) != 14 {
-		t.Errorf("the mesh defines %d seats rather than 14; the set is closed, so a change here is "+
+	if len(Seats()) != 15 {
+		t.Errorf("the mesh defines %d seats rather than 15; the set is closed, so a change here is "+
 			"a decision (novox/hq ADR 0110): %s", len(Seats()), seatNames())
 	}
 }
 
+// novox/hq ADR 0117: a machine's uplink is a seat, held per machine, and delivers nothing.
+//
+// **Nothing, because nothing may be required of it.** A holder only keeps its network manager from
+// contradicting the mesh; a requirement resolving to it would make the manager the mesh's answer
+// for something, and the manager's link is the one thing the mesh must never be able to break.
+func TestTheUplinkIsANodeSeatThatDeliversNothing(t *testing.T) {
+	seat, known := SeatNamed("the-uplink")
+	if !known {
+		t.Fatalf("the uplink is not a seat; the seats are: %s", seatNames())
+	}
+	if seat.Scope != ScopeNode || seat.Delivers != "" || seat.Decision != "novox/hq ADR 0117" {
+		t.Fatalf("the uplink is %+v, not a node seat delivering nothing by ADR 0117", seat)
+	}
+	// And a manager's module can hold it without providing anything.
+	raw := []byte(`{"module":"networkmanager","version":"1","claims":[{"name":"the-uplink","scope":"node"}]}`)
+	if _, err := ParseManifest(raw); err != nil {
+		t.Fatalf("a network manager's module could not hold the uplink: %v", err)
+	}
+}
+
 func claimed(claims string) []byte {
 	return []byte(`{"module":"thing","version":"1","provides":[{"name":"npm-package-registry","scope":"mesh"}],"claims":` + claims + `}`)
 }