Every chaos scenario draws n01 at the top of its topology, and until now that
held in three of thirteen. The mesh roots itself at the numerically smallest
NodeAddr, which is a hash of the node's public key and bears no relation to the
node numbering, so which node ended up as root was effectively arbitrary.
The consequences were not cosmetic. cost-reeval rooted at n04, its own
designated test subject, so that node had no parent and the periodic parent
switch the scenario exists to observe could not occur at all. mixed-technology
rooted at n09, which put its two documented parent criteria out of reach and
made correct cost-based selection look like a defect.
Identities are still derived from the mesh name exactly as before and are still
deterministic. What changes is which node id holds which one: they are now
assigned in NodeAddr order, so n01 holds the smallest and is the root. Verified
against a model of the daemon's own derivation that reproduces the previously
observed root for every scenario and n01's address byte for byte; all twelve
pinned scenarios now root at n01.
smoke-10 deliberately opts out via pin_root: false so that root election from an
arbitrary key distribution stays exercised somewhere. Its assertion is a
convergence floor and is root-agnostic, which is why it is the cheapest home for
that. The new key is rejected when non-boolean, and a near-miss spelling is
rejected as unknown; both checked.
Not yet established: the trees themselves change, so the parent-dependent
assertions in bottleneck-parent, cost-avoidance and cost-stability need
re-deriving against live runs. Those are held until the in-flight CI finishes,
because a chaos run rebuilds the shared fips-test image that run is using.
Johnathan Corgan