Supersedes 0032, which decided the right thing and described it wrongly.
The decision is unchanged: the account that installed the host owns the
mesh, and there is no user model.
What was wrong was inventing "a surface that delegates authentication"
for the board. It is a web application with a login, in the way every
web application has a login. That is a fact about an application, not a
property of the mesh.
The cost was not cosmetic. It made the identity module look like part of
the mesh's authority — something the mesh depends on to know who anybody
is — when the mesh knows nothing about people at all and one of the
applications running on it happens to have a login.
Keeps the line that is worth writing down, and states it more plainly:
signing in to an application must not become authority over the mesh.
Today it cannot, because the board reads and does not act. The moment it
can assign a module, whoever it lets in has mesh authority — and it
would arrive as a feature rather than as a decision. So a surface that
can change the mesh is a change to who owns the mesh, and is taken as
one. Not forbidden; just not something that turns up in a pull request
titled "add assign button".
Answers what 0031 left open, and a question it did not ask — who owns
the mesh at all. There was no answer, and the absence was invisible
because every operation so far has been run by the person sitting at the
machine, so nothing had to say whether that was the design or the
circumstance.
The account that installed the host owns the mesh on that node. No user
model, no roles, nothing to administer. It follows from 0004 rather than
adding to it: there is no authorisation between nodes because every node
is the operator's own, so a user model inside that boundary would guard
nothing — anyone it could stop could read the node's key off the disk.
The board is different, and the difference is the network. A surface
reachable by a browser has to know who is asking, because those people
are not by construction people with a shell on the machine. So it
delegates to an OAuth provider, which is a module.
That does not make identity substrate. A surface delegating
authentication is not the control plane delegating it: the control plane
runs, applies declarations and reaches nodes with no identity provider
in existence. Only the board needs one.
Records the cost plainly: anybody with a shell on a node has full
authority there, and there is no way to give somebody authority over one
node without giving them a login on it.
jschoubben