An archive had no removal, so an unassigned one failed as an orphan and
aborted every apply after: a module with tools could not be unassigned,
and a race between two pushes froze a machine against every change.
The record now keeps what an archive unpacked: its files, the
directories the host made inside its path, whether the host made the
path itself, and the parents it made to reach it. Removal takes exactly
that away, directories only once empty, never one that was there
before; a directory that is the host's alone is renamed aside first so a
reader sees the whole bundle or none of it. Whatever cannot be removed
is said and forgotten, never fatal.
A directory found before the archive is no longer swapped away with
what was in it: the archive is moved in file by file, and one that would
write over a file the mesh did not put there is refused before anything
moves. A record from before this change learns its files from the
archive's bytes on the next apply; one already orphaned is left in
place, said and forgotten. A former target is still left in place: the
version before is what a rollback starts (ADR 0141).
A file or archive placed under a fresh account's home with an owner left
the parents it created, such as ~/.config or ~/.local/share, owned by
root, so the person's own programs could not write there. Parents that
already existed, and any outside the owner's home, are left as before.
Unpacked over the previous tree, a file the new archive no longer has stayed: a bundle rebuilt as
one file per entrypoint kept the old package directory. Unpack into a fresh directory and swap it
in, so a refused archive also leaves the old tree whole.
not a service
A shell, a terminal, a chat client, a desktop are a package plus
configuration in somebody's home. A mesh with no notion of a user can own
/etc and nothing anybody looks at, which is most of the reason to manage
a machine at all.
Three shapes, and the vocabulary test asserts the count precisely because
widening it widens what a compromised control plane can express:
user a login, its shell and its groups
archive a set of files, fetched by digest and unpacked
(file) gains `bytes` for what is not text, and `owner`
`user` also makes "zsh is my login shell" declared state. chsh is a
command, the link may not carry one, and a shell settable only by hand is
a shell the mesh cannot manage.
Groups are additive and never pruned — usermod without --append REPLACES
them, which would silently remove every group that makes a login able to
use the machine. A machine's own groups are not the mesh's to know about.
The archive is the one place this host reaches out on its own; everywhere
else it holds one outbound connection and fetches nothing. So it carries
the discipline the bootstrap already uses for images: pinned by digest,
and the digest checked before a single file is written.
Two decisions in the unpacker worth naming:
- an entry naming a path outside the archive is REFUSED, not sanitised.
Rewriting it to land inside would put a file somewhere nobody asked for
and report success. Found by the test: the first version quietly
relocated it.
- symlinks and device nodes are refused rather than skipped, or an
archive that needed one arrives silently incomplete.
A partial host does archives and refuses users: an archive needs a
filesystem and a way to fetch; a user needs a user database it is allowed
to write.
jochen
jschoubben