host-install v1.13.0: systemd-journal group for the agent user + NAS feature doc
The NAS verify pipeline (agent v0.81.0) reads mount-unit journals unprivileged — group membership, NO sudoers grant. Fixes the v1.11.0/1.12.0 header drift. New authoritative feature doc documentation/controller/network-storage-nas.md (verify pipeline, §8 truth table, Q4 error taxonomy, retry=0, Route A recipes incl. the chmod-persists nuance). Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01PSK5g6qYLknKj8u3QAFEr6
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# Network storage (NAS) — bulk-media shares with verify-before-commit
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**Status:** authoritative feature doc, code-verified against felhom-agent v0.81.0 +
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felhom-controller v0.113.0 (2026-07-11).
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**Evidence base:** `documentation/audits/SPIKE-nas-storage-2026-06-29.md` (the locked mount recipe)
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and `documentation/audits/SPIKE-nas-verify-2026-07-11.md` (the verify mechanisms, squash matrix,
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error taxonomy — commit b57f6c1). Code: agent `internal/storage/netmount.go` /
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`internal/storage/netverify.go` / `internal/localapi/netverifyjob.go`; controller
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`internal/web/netstorage_job.go` / `internal/web/netprobe*.go`.
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## What it is
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A customer's NAS serves **bulk media** (film, photo, music) to media apps. The share is mounted
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**host-side** by the agent under `/mnt/felhom-drives/<name>` via a systemd `.automount` + `.mount`
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pair (on-demand + idle-unmount), propagates into the guest through the existing shared `mp8` bind,
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and is selectable as a media app's data path. A NAS is a **distinct storage class from a drive**:
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no durable-id, no SMART, no enroll/eject/decommission/wipe/migrate — remove is the only lifecycle
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action (`refuseNetworkLifecycle` blocks the drive verbs).
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## The locked mount recipe
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- **NFS (nfs4):** `vers=4.1,soft,timeo=50,retrans=2,noatime,_netdev,retry=0`. `soft` = failure
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isolation (clean EIO, never a wedge). **`retry=0`** (SPIKE-nas-verify Q4-vi): without it a
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dead-NAS on-demand access wedges the accessing app until systemd's 90 s start cap (measured
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91 s); with it the access fails clean in ~3.8 s (ENODEV) and each autofs re-access is a fresh
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attempt. `retry` only governs retrying a FAILED first attempt — the happy path is untouched.
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The uid mapping is the EXPORT's job (squash), never the client mount.
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- **SMB (cifs):** `vers=3.0,credentials=<0600 file>,uid=<uid+100000>,gid=<gid+100000>,forceuid,
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forcegid,file_mode=0664,dir_mode=0775,_netdev`. No `retry=` (a mount.nfs option; mount.cifs
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rejects it). Credentials live in an agent-written 0600 file, never in the registry, never
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controller-persisted.
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- **The +100000 rule:** container uid/gid N = host N+100000 (unprivileged-LXC idmap).
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## Verify-before-commit (the add pipeline)
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`POST /api/storage/netstorage/add` never registers blind. The controller orchestrates
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(detached job, single-flight, ~150 s budget, status on `GET /api/storage/netstorage/add/status`):
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1. **agent add** (`POST /netstorage/add`): role-gate → **sync fast-fail** (spec validation + 2 s
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TCP pre-probe; an unreachable server is refused with NOTHING installed) → stage SMB creds →
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install unit pair + enable the automount → start the agent's detached verify job.
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2. **agent verify** (polled on `GET /netstorage/verify-status` every 2 s): a directory read
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through the automount triggers a REAL mount (spike Q1: an in-guest or host-side access wakes
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it, ~1 s LAN); success is judged from **/proc/mounts only** (truth table below); a failure is
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classified from the mount unit's journal and **auto-rolled-back** agent-side (units + creds).
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3. **in-guest uid-1000 write probe:** the controller re-execs itself
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(`felhom-controller --netprobe <dir>`) with `SysProcAttr.Credential{Uid:1000,Gid:1000}` —
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create a `.felhom-proba-<random>` dot-file, write a nonce, read back, compare, delete. This
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catches the **squash trap**: an export that mounts fine but denies every uid-1000 write
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(spike Q3 row c). A failed delete after a good write is a WARN, not a failure.
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4. **register** (`AddStoragePath`, Kind=network, Schedulable) — **the LAST step**. The worst
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crash outcome is an agent-side orphan (surfaced in the list as a remove-only "Árva megosztás"
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row), never a registered-but-broken path.
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Any failure = **full rollback**: nothing registered, no units left installed, no creds file.
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If the agent restarts mid-verify, its in-memory verify slot reports phase `none`; the controller
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treats that as verify-lost and rolls back (the orphan row is the belt-and-braces surface).
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### Mount-success truth table (SPIKE-nas-verify §8)
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| Trigger `ReadDir(where)` | /proc/mounts shows nfs4/cifs at where | Verdict |
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|---|---|---|
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| ok | yes | mount OK → the uid-1000 probe decides writability |
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| EACCES / EPERM | yes | mount OK (the agent user just can't read it — a 0700 export is fine) |
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| any result | no | mount FAILED → classify from the journal |
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| still blocked at 95 s | — | `timeout` (black-holed-but-routed; systemd's 90 s cap resolves it) |
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Readability is NEVER the truth source — /proc/mounts is.
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### Error taxonomy (live-measured; classification is string-based BY DESIGN — every failure is rc=32)
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| Category | Journal substring (verbatim) | Meaning |
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|---|---|---|
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| `unreachable` | `No route to host` / `Connection refused` / `Connection timed out` (or the 2 s sync pre-probe) | no NAS behind the address |
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| `nfs_export` | `reason given by server: No such file or directory` | export missing **OR not permitted — MERGED**: NFSv4 returns the identical string for both (Q4 ii≡iii); the customer message names both possibilities |
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| `smb_auth` | `mount error(13)` | wrong SMB username/password |
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| `smb_share` | `mount error(2)` | SMB share name not found |
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| `timeout` | `Mounting timed out. Terminating` | routed but not answering (systemd 90 s cap) |
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| `mount_failed` | (none matched / journal unavailable) | generic; detail carries the raw journal |
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| `not_writable` | (probe exit 2) | mounts, but uid-1000 cannot write — the squash trap |
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| `probe_io` | (probe exit 3) | write readback failed/differed |
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The journal is read **unprivileged** (`journalctl -u <unit> -n 20 -o cat`): the agent user is in
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the `systemd-journal` group (host-install ≥ v1.13.0 adds it; existing hosts:
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`usermod -aG systemd-journal felhom-agent && systemctl restart felhom-agent`). **No sudoers
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grant** — journal access is group-based by rule. Journal unavailable degrades to `mount_failed`
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with a hint; the rollback still runs.
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## NAS-side recipes (protocol-honest guidance — what the UI tells the customer)
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- **SMB (Synology, QNAP — the consumer default, listed FIRST in the UI):** a plain user account
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with rw on the share is sufficient — **zero server-side uid configuration** (spike Q5). Files
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land on the NAS owned by the connecting account; the client mount forces the guest view to
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uid/gid 1000. Hardlinks worked on Debian Samba/ext4 — re-verify per appliance.
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- **NFS, simple recipe (Route A — spike Q3 row b, ACCEPTED):** enable "map all users / all
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squash" on the export, rw, to ANY local user. The guest-uid-1000 app gets full
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read/write/rename/**hardlink**/delete. Caveats:
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- guest-visible ownership is `nobody:nogroup` (65534) — cosmetic for apps that just read/write;
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- `chown` fails with an immediate clean EPERM (no hang);
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- **`chmod` SUCCEEDS and persists server-side** (the squashed identity owns every file) — modes
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are app-controlled; operators should know a mode change on the NAS side is real.
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- **NFS, full-fidelity recipe (TrueNAS / Linux server):**
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`rw,all_squash,anonuid=<uid+100000>,anongid=<uid+100000>` (e.g. 101000 for a uid-1000 app) —
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ownership information is exact end-to-end.
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- **The pinned WRONG case (what `not_writable` usually means):** `anonuid=<x>` **without**
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`all_squash` is a no-op for non-root traffic — the app's wire uid (101000) hits the export
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unmapped and fails on others-perms. The consumer recipe REQUIRES the map-ALL-users mode; an
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anonymous-uid field alone does nothing. The UI's `not_writable` message and the guidance block
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tell this same story.
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## Health model
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Per-share liveness only (`ok | idle | unreachable`): `idle` (automount idle-unmounted) is the
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benign steady state; `unreachable` degrades the affected share's apps ONLY — never box health,
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never the drive missing→stop cascade (kind-gated). Timing/budget note for integrators: the verify
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worst case is systemd's 90 s (black-holed server) — verify traffic therefore rides the detached
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job + status poll, never a single long HTTP call (the agentapi client keeps its global 15 s
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timeout).
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## Open items
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- Q1c: whether an automount trigger installed BEFORE guest boot propagates at guest start —
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needs a restart-window test (the add flow installs while the guest runs, which is proven).
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- Synology/QNAP appliance fidelity pass (virtual-dsm) before GA.
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- The demo's pre-existing `nas-media` unit (if any) predates `retry=0` and is not rewritten —
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re-adding the share re-creates it with the current option string.
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