# NFS Self-Heal (host-level systemd units)

These files are **not** deployed by Docker/Portainer — they're systemd units and a
script that live directly on the host at `/etc/systemd/system/` and
`/usr/local/bin/`. They're checked in here purely as a backup so they can be
restored if the host is rebuilt. Editing a file here does **not** change
running behavior; you have to re-copy it to the host and reload systemd.

## What this does

Permanent NFS mounts (`mnt-nas_family.mount`, `mnt-nas_books.mount`,
`mnt-nas_owncloud.mount`) can go stale — the host mount looks fine on a
top-level `ls`, but file handles nested inside it return ESTALE
(errno -116) to processes that opened them earlier, including containers
that bind-mount the path. A container restart is required to pick up a
fresh handle even after the host-side mount is healthy again. See
`../../NAS-CONNECTION-STRATEGIES.md` for the full mount inventory and
`../../immich/` / `../../calibre/MOUNT-HISTORY.md` for history on this
failure mode (first hit immich on 2026-08-25; calibre-import had the same
issue documented earlier but unresolved).

Two pieces:

1. **`<container>-mount-ready.service`** (one per affected container) —
   `BindsTo=mnt-nas_*.mount`, so restarting the mount unit automatically
   restarts the bound container. Currently covers `immich_server`,
   `calibre`, `ocis`. (Older instances of this same pattern —
   `backrest`, `kiwix`, `pmtiles`, `audiobookshelf`, `romm` — already
   exist on the host but aren't backed up here yet.)
2. **`nfs-mount-heal.timer`** → **`nfs-mount-heal.service`** →
   **`nfs-mount-heal.sh`** — runs every 5 minutes, does a real nested
   read (not just `ls` the mount root) against `nas_family`, `nas_books`,
   and `nas_owncloud`. On failure it force-remounts the mount unit
   (`systemctl restart`), which cascades into the container restart via
   the hooks above, then re-checks and sends a Telegram alert either way.

## Reinstall after a host rebuild

```bash
sudo cp *.service *.timer /etc/systemd/system/
sudo cp nfs-mount-heal.sh /usr/local/bin/nfs-mount-heal.sh
sudo chmod 755 /usr/local/bin/nfs-mount-heal.sh

sudo systemctl daemon-reload
sudo systemctl enable --now immich-mount-ready.service
sudo systemctl enable --now calibre-mount-ready.service
sudo systemctl enable --now ocis-mount-ready.service
sudo systemctl enable --now nfs-mount-heal.timer
```

Requires the `mnt-nas_family.mount`, `mnt-nas_books.mount`, and
`mnt-nas_owncloud.mount` systemd units to already exist (see
`NAS-CONNECTION-STRATEGIES.md`) and `.credentials` at the repo root to be
present on the host (the heal script sources it for the Telegram bot
token/chat ID).