jhodgkin
5143840d90
Single-file bind mounts pin the container to that file's inode at mount time. sed -i and most editors write-then-rename (atomic write), which swaps in a new inode at the same path -- the container kept reading the orphaned original and never saw edits, silently breaking the hot-reload from the previous commit. Caught by actually testing the reload live instead of trusting the code. Directory mounts resolve paths dynamically and don't have this problem. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
32 lines
1.9 KiB
Markdown
32 lines
1.9 KiB
Markdown
# Editing monitored hosts without a redeploy
|
|
|
|
`config/hosts.yaml`'s `sshHosts` and `knownDevices` lists are re-read on the next poll
|
|
cycle (checks the file's mtime, reloads if changed) — no container restart needed.
|
|
|
|
- **Proxmox-monitored hosts** (the node + every LXC) need no config at all — they're
|
|
auto-discovered from the Proxmox API on every poll already.
|
|
- **SSH-monitored hosts** (`sshHosts`): edit `config/hosts.yaml` on the deploy host
|
|
directly (`/opt/homelab-monitor/config/hosts.yaml` on CT122), save, wait up to one
|
|
poll interval (`POLL_INTERVAL_SECONDS`, default 30s). Adding a *new* SSH host still
|
|
needs a one-time manual step first — installing the forced-command key on the target
|
|
(see `docs/ssh-collector-key-setup.md`) — that part can't be automated away, so a web
|
|
form wouldn't make this fully self-service regardless of hot-reload.
|
|
- **`knownDevices`** (device discovery labeling): same file, same reload path, no
|
|
manual step needed since it's just a label list.
|
|
|
|
If the file fails to parse (bad YAML), the error is logged and the **previous**
|
|
in-memory config keeps running rather than crashing the poller.
|
|
|
|
## Gotcha that broke this on first deploy
|
|
|
|
`docker-compose.yml` originally bind-mounted the single file
|
|
(`./config/hosts.yaml:/app/config/hosts.yaml:ro`). Single-file bind mounts pin the
|
|
container to that file's **inode** at mount time. `sed -i`, most text editors, and any
|
|
tool that does an atomic write (write to a temp file, then `rename()` over the
|
|
original — the common safe-write pattern) swap in a *new* inode at the same path. The
|
|
container kept reading the original (now-orphaned) inode and never saw edits made this
|
|
way, no matter how long you waited for the next poll cycle. Fixed by mounting the
|
|
**directory** instead (`./config:/app/config:ro`), which resolves paths dynamically
|
|
rather than pinning to a specific inode. Confirmed via `docker exec ... stat` showing a
|
|
stale mtime that didn't match the host file before this fix.
|