The launcher trusted a counter only a by-hand reconcile ever cleared and a
known-good nothing in the daemon wrote, so no machine could roll its host back;
the controller and the node tools were replaced in place with nothing kept.
- The launcher runs a delivered host that is not known-good on trial: one that
crashes, stops for nothing, or does not report within ten minutes goes back
to known-good, once per version, recorded in rolled-back. The host proves
itself when the mesh takes a report under its own build, says every standing
verdict on its reports, never stands aside for a rolled-back version, and
restarts its service once when its launcher was replaced on disk.
- The engine keeps the controller's and the node tools' previous build beside
the new one and judges the new one: the lease taken by the controller it
started (read-only direct get of mesh-controller_lease/holder), or this
machine's runtime answering $SRV.PING.node-tools.<node>, within sixty seconds
of time it could ask. Not healthy: the previous restored, once, said. Proved:
the previous deleted. A build declared not-reversible is never rolled back.
- Retire never removes a version newer than the running one.