diff --git a/04-ISSUES/169-a-machine-shares-its-files-and-the-mesh-does-not-know/00-report.md b/04-ISSUES/169-a-machine-shares-its-files-and-the-mesh-does-not-know/00-report.md new file mode 100644 index 0000000..addacf0 --- /dev/null +++ b/04-ISSUES/169-a-machine-shares-its-files-and-the-mesh-does-not-know/00-report.md @@ -0,0 +1,128 @@ +--- +status: open +opened: 2026-09-30 +located-in: + - mesh-catalog (no module shares a path over the network) + - hq 02-DECISIONS (a file-share seat, per ADR 0126, is a module's own to define) +fixed-by: +amended-design: +--- + +# 169 — A machine shares its files, and the mesh does not know + +## What was observed + +ace serves the operator's media library to the home network with two host services no module +declares and HAL never managed either: + +``` +/etc/exports: /storage/media 192.168.1.0/24(rw,sync,root_squash,…) nfs-server active, :2049 +/etc/samba/smb.conf: [media] path = /storage/media/ valid users = media smb active, :139/:445 +``` + +Two LAN clients were connected at survey (2026-09-30). The library itself is operator data +(ADR 0051: ~40 TB on ZFS, the mesh owns nothing about it — [issue 153](../153-an-adopted-machines-data-cannot-be-placed-where-it-is/00-report.md) +is about modules reaching it in place). + +Under the mesh as it stands, this arrangement has no expression and one failure mode: + +- **Nothing declares the listens.** At `converge ace` the filter is the sum of what modules listen + on (ADR 0045); 2049 and 445 are nobody's, so the shares close — silently, for the two clients + that mount them. +- **Nothing owns the configuration.** `/etc/exports` and `smb.conf` are hand-written files on one + machine; a second machine sharing a directory would be written by hand again. +- **Nothing can consume it.** A module on another node that wanted the library (a player, an + indexer, a backup) has no `requires` to state and no binding to read; it would mount by a + hand-typed host and path. +- The clients are LAN devices, so this also meets [issue 154](../154-a-machines-own-network-is-not-a-reach/00-report.md) + (no reach for the machine's own network). + +## The proposal (the operator's, 2026-09-30, settled after two rounds) + +**Two module-defined seats, one per protocol, because NFS and SMB share an intent and not a +contract.** A seat in the mesh's sense is a contract — what it accepts, emits and serves, and the +tools its holder must answer (ADR 0126, 0132) — and lined up, the two share almost none of it: + +| | `nfs-share` | `smb-share` | +|---|---|---| +| serves | export path(s); the client ranges allowed (`sec=sys` authorises by address) | share name(s), path | +| pair credential | none | a user and password per consumer | +| consumer's mount | `at:/path` | `//at/share` with credentials | +| holder's tools | export / unexport a path for a range | add / remove a share, create a user | + +One `file-share` seat would be the union with every field optional — a consumer could bind it and +still not know how to mount what it got (the emptiness ADR 0129 warns against). "Export a path to +the network" is a category, and the mesh needs no seat category: a consumer requires the one it +can mount. If "give me the library, however" is ever needed, it is a provision an umbrella module +serves, not a seat. + +Both are node-scoped, one holder per node (ADR 0110), so ace holds both. `nfs` and `samba` are the +first implementations; a second (Ganesha for `nfs-share`, ksmbd for `smb-share`) is what proves +0126's promise that "replacing the implementation changes nothing for any caller". + +The holder module: + +- declares the exported paths as `accesses` (ADR 0051: it owns nothing about them — never creates, + chowns or removes), and *which* paths as the assignment's settings (ADR 0046/0112); +- writes the share configuration (`/etc/exports`, `smb.conf`) as mesh-managed files and drives the + units, like `dnsmasq`/`sshd` do for theirs; +- declares its endpoints (`nfs` 2049/tcp; `smb` 445/tcp, …) so the reach — internal, or the LAN + once 154 has an answer — is the assignment's, and converge keeps them open; +- **provides** the seat's provision, so a consumer on another node `requires nfs-share` (or + `smb-share`) and reads `${bound:nfs-share:at}` and the path from its binding instead of a + hand-typed mount. + +## The design gap this exposes + +**A seat definition has no home outside the module that first declared it.** Today a seat is +declared inside a manifest (`showcase` declares `the-showcase`, `ca-trust` its own). If `nfs` +declared `nfs-share`, Ganesha could hold it only by depending on nfs's manifest — the coupling +0126 removed for callers, reintroduced for implementations. The protocol needs a neutral place in +the catalogue beside the modules (a seat definition registered like a manifest), with a module +saying which seats it implements. This is the first role with an obvious second implementation, +which is what makes it the exemplar for that mechanism. + +## The consumer's half: a module mounts it (2026-09-30, third and fourth round) + +A binding tells a consumer *where* the share is; it does not put the files on its machine. Mounting +is something done on a machine, and something done on a machine is a module's work — not the host's +(the vocabulary stays closed; no `mount` resource kind). + +**A consumer-side module, `network-share` — the module responsible for setting up the network +shares a node uses** (the operator's framing). A node role, like `node-uplink` or +`node-dns-resolver`: each machine has it at most once, which is a reason for it to hold a +node-scoped seat, so two modules can never both be writing mount units on one machine. Assigned on +the node that wants the files: + +- `requires nfs-share` (or `smb-share`); several shares on one node are several local names of + the requirement (ADR 0094); +- its manifest is a `package` (nfs-utils), a `file` writing a systemd `.mount` unit filled from + the binding — `What=${bound:nfs-share:at}:${bound:nfs-share:path}` — and a `service` enabling it + after the overlay is up: the same shape as `resolv-conf` or `sshd`, files and a unit; +- *where* it mounts is the assignment's setting (`/srv/media` on one machine, elsewhere on + another); which machine mounts what is an operator decision made at assignment, exactly as which + paths a machine shares is. + +**The modules that use the files never learn about NFS.** A player, an indexer, a backup declares +the mounted path as an `access` — an operator-chosen, pre-existing path the mesh never owns +(ADR 0051), exactly as `/storage/media` is on ace. The same app manifest then runs on ace against +the local library and on another node against the mounted one, with only its assignment differing. + +**The one check to add, because it is the data-loss case.** An `access` is confirmed today by the +path being present. For a mountpoint that is not enough: a writer whose container starts before the +mount is up writes into the empty directory underneath it, and the files vanish when the mount +lands. The access check must confirm the path is *a mountpoint* when the module says so (or the +module's unit is ordered before the consumer's container — which crosses modules and is exactly +what the mesh does not order). Which of the two is the decision's. + +**Identity crosses the wire.** `sec=sys` NFS trusts the client's uid, so a consumer must run as the +library's owner on the server (ace: `media`, 1001:2000) — hq 153's `${access::uid}`, read from +the mounted tree, answers it on the consumer's side too. + +## Open questions for the decision + +- Whether an NFS export over the overlay is an `internal` reach of the same endpoint or a second + export line — NFS authorises by client address, so the mesh range and the LAN range are two + entries in one file. +- How a consumer's binding expresses a *path* to mount (today bindings carry `at`, `port`, `as` and + whatever the provider `serves`), and whether one share can serve several paths.