A tier test as a decision procedure — five ordered questions, first match
wins — so placement is answerable rather than argued.
Postgres was the test case and the naive answer is wrong. Not twice, once:
the control plane cannot exist without a relational store, so it is tier 1
and lives in hal-substrate/store/postgres. What differs between the mesh's
own database and a project's is not the module but how that instance is
brought up — pinned bundle applied by the host, versus the ordinary
delivery and provisioning path. Tier is a property of the module; the
bundle is a property of the mesh's own instance. The naive answer would
also have made substrate reach up into the catalogue, which the dependency
rule forbids.
Working the test across the catalogue surfaces a third fate that neither
of research 005's options covers, and it is the most common one: absorbed
into the host, ceasing to be a module at all. That explains 005's one
positive measurement rather than confirming it — the reachability cluster
is not four modules that should be one domain module, it is four facets of
one thing the host should own, expressed as modules because a module was
the only unit available. Under this skeleton the overlay and firewall
modules stop existing. It also partly answers the silent fifty: several
are host concerns, so silence was the right signal and grouping was the
wrong inference.
Flags rather than settles: the identity provider is a genuine boundary
case (four substrate services or five), and absorbing six concerns into a
binary whose argument is that it has no dependencies is the skeleton's
biggest unproven claim.
jschoubben
7a20358113