The controller's machine moves it from the container to a process by
starting the process first and removing the container once the process
is up (mesh-host's `replaces`). For that moment two controllers share the
store and the bus. Checked what each does:
- the seat's verbs: a queue group per seat, each call answered once. Safe.
- the controller's consumers on CONTROL and EVENTS: push consumers with
no delivery group, so the second bind is refused with "consumer is
already bound" and serve exited. The process would restart for ever,
the host would never see it up, and the container would never go. The
second controller now stands by and binds when the first lets go
(tested on a real bus; fails without the change).
- plans: read, changed and saved whole by the 30s timer, by build
outcomes, by a merge and by `plans stop`. Two timers would each ask a
tier the other had just asked. Working the plans now takes a
session-level advisory lock on the inventory: the timer skips while
another holds it, the other paths wait for it. Build asks happen only
inside plan work and are covered by the same lock.
jochen
e11caecdad