A module's containers ran as whatever their image chose and shared folders were
made writable by putting accounts in the folder's group (ADR 0312), which ADR 0325
supersedes. The engine now makes each declared module identity as a system account
with the controller's numbers, runs a container declaring `identity` as it, and keeps
each placed shared folder usable through one POSIX ACL entry per user, set through
the kernel's xattrs on descriptors it opened itself. A folder holding data is kept
only after the operator's warrant (the take act); a missing folder is made where its
data lives and waits where its disk is not; root's data is never kept. A watch and a
bounded sweep put back what an app narrows. The group grant is removed, and what it
put an account in is taken back.
Reuses the descriptor walks, the create act, the missing-path wait and the warrant-
backed act message from the paused issue 567 branch.
The engine reads the group owning the accessed path at apply and gives it to the
containers and the tools' account an access's new `grant` names: --group-add for a
container (recreated with it), an account group for the account (recorded, taken
back as ADR 0252 takes back). The path is never changed; an access whose group
cannot write is stated unhealthy for the operator to decide; group 0 and the
root-granting groups are refused by name. The tool runner restarts through the
restart-on the controller gives it, because the access reports updated exactly
when the account's groups moved. Health says GrantContract (4), which tells the
controller it may send `grant`.
A container resolves every machine and public name through the entries it is given when it is created,
and nothing re-reads them. The host compared everything about a container except those, so one whose
image and files never changed was left alone holding an overlay address five days out of date — it
restarted 2286 times against a database it could no longer find, and the mesh reported the machine as
doing what it was told (novox/hq 04-ISSUES/135, the same fault as 045 in the field left out).
Sorted, so the digest does not move for a reordering nobody made. The first apply after this recreates
every container that carries mesh names, once.
jschoubben