One assignment of a module per node is now the rule, not a limitation —
the operator dropped the multi-assignment requirement, and the schema's
(node, module) key has been the decision since migration 0005. What
changed: Assign reports whether the assignment was new, and the command
says 'already runs — one node runs one of each (ADR 0115); nothing
changed' instead of printing 'is assigned' for a no-op, which read as
an action that happened. Idempotence stays: a repeat is exit 0, because
a script stating what is already true is not wrong.
Review of the ADR 0105 build (hq ADR 0105). Four things it got wrong and one
path it lacked:
- A predecessor spoke's tunnel names one peer, the hub, routed the whole
range; recording refused it and the whole enrolment failed. Range-routed
peers are skipped now — only the hub's peers are ever carried.
- The range and the carried peers were conditions on the node being adopted,
so converging the hub would have renumbered the mesh and dropped the peers
still reaching it. They are facts of the tunnel record now, mode aside; the
takeover alone is declared to an adopted node. Converging the hub is refused
while a carried peer has not enrolled, naming it.
- A push composed a takeover for a hub whose address or endpoint disagreed
with the tunnel, which would have the host stop the found interface and
raise the mesh's where no peer listens. The graph refuses to compose it,
naming both and the placement that fixes it.
- The host's account said taken or not; "found down and the mesh's not up"
read as not taken. Three states now, and an account on every takeover.
- A hub that enrolled before this feature holds a key of its own, and
re-enrolling would rotate every key the mesh sealed credentials to. A node
now rekeys in a report, signed with its identity key over the key it
leaves, the key it takes and the tunnel; the mesh verifies against the live
key, refuses a stale or foreign proof, records key and tunnel, and moves a
hub to the tunnel's address. `overlay show` names the path for a hub that
found no tunnel.
Also: a carried IPv6 peer is routed /128, and identity.ForTest exists so the
link can be tested against a real identity store.
On an adopted hub the private network takes over the tunnel it finds rather
than running beside it (hq ADR 0105): two tunnels leave the mesh's unreachable
through the provider's filter, so no machine can ever join.
The node presents the found tunnel when it enrols, under the key it took as
its own; the inventory records it (node.tunnel, tunnel_peer — migration 0031)
and the mesh composes from it: the overlay's range is the adopted tunnel's,
the hub is placed at the tunnel's address on the tunnel's port, and every
peer the tunnel had is carried in the hub's peer list as a peer of the
tunnel, not a node of the mesh, until a node enrols with that key — which
then keeps the address the tunnel had for it. A fresh node never gets an
address the tunnel holds. The hub's declaration tells the host which unit to
take over; the host's account of carrying it is recorded and shown.
Every reader of the range follows the setting; nothing stores it. A found
tunnel under another key is recorded and not adopted, so ADR 0100's
non-overlap rule keeps applying where a tunnel is left running beside the
mesh's. A lab bed and test skeleton for "How it is checked" are under lab/.
jschoubben