Files
oikos/archive/hermes-plans/2026-06-05_170000-prevent-dhcp-ip-drift.md
dtoro 6b75f7302d db as source of truth: wiki→seeds, archive old artifacts, knowledge ingestion
- Migrations 010 (content_hash) + 011 (search tsvector column)
- new: internal/knowledge/seed.go — knowledge seed ingest engine
- new: internal/httpapi/knowledge.go — SearchKnowledge + GetEntityKnowledge
- wire knowledge ingest into oikos seed pipeline
- convert all 36 wiki docs + 6 investigations + 12 runbooks → seeds/knowledge.yaml
- archive: knowledge/wiki/→archive/, oikos/cards/→archive/, .hermes/plans/→archive/
- delete: 9 superseded Python kernel files, ledger/, mcp/build_host_files.py
- remove empty knowledge/ directory tree
2026-07-07 20:22:30 +02:00

129 lines
6.4 KiB
Markdown
Raw Blame History

This file contains ambiguous Unicode characters
This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.
# Plan: Prevent DHCP IP drift from breaking Caddy backends
**Date:** 2026-06-05
**Slug:** prevent-dhcp-ip-drift
---
## Goal
Eliminate the root cause of services becoming unreachable when DHCP lease renewals change backend IPs that Caddy's `reverse_proxy` directives hardcode.
**Triggering incident:** Paperless (LXC 103) and HAOS (VM 108) had DHCP-assigned IPs change from `.130→.243` and `.101→.241` respectively. Caddyfile still pointed at the old IPs → services unreachable from iPhone on Netbird.
## Current context
### DHCP vs static IP inventory
| Machine | Type | PVE ID | Current IP | Allocation method | Status |
|---------|------|--------|-----------|-------------------|--------|
| **jellyfin** | LXC | 101 | 192.168.8.206 | Static (`ip=.../24`) | ✅ |
| **paperless** | LXC | 103 | 192.168.8.243 | **DHCP** (`ip=dhcp`) | ❌ broken, hotfixed to .243 |
| **gitea** | LXC | 104 | 192.168.8.121 | Static | ✅ |
| **apps** | LXC | 105 | 192.168.8.205 | Static | ✅ |
| **nextcloud** | LXC | 114 | 192.168.8.224 | Static | ✅ |
| **elementsynapse** | LXC | 118 | 192.168.8.239 | Static | ✅ |
| **mule-images** | LXC | 120 | 192.168.8.136 | Static | ✅ |
| **caddy** | LXC | 121 | 192.168.8.175 | Static | ✅ |
| **arriman** | LXC | 122 | 192.168.8.132 | Static | ✅ |
| **sophia** | LXC | 119 | 192.168.8.157 | Static? | ? (not in 2026-06-02 list) |
| **nfs-export** | LXC | 102 | 192.168.8.200 | Static? | ? |
| **plato** | LXC | 126 | 192.168.8.190 | Static? | ? |
| **HAOS** | VM | 108 | 192.168.8.241 | **DHCP** (VM — OS-managed) | ❌ broken, hotfixed to .241 |
| **zimaos** | VM | 100 | 192.168.8.195 | DHCP (known stale lease, see note) | ⚠️ open issue |
| **authentik** | — | — | — | migrated to VPS (external) | N/A |
### Infrastructure facts
- **DHCP server:** Technitium on CT 107 (192.168.8.2), pool `.241.254`
- **Static IP range:** `.101.239`
- **DNS:** Split-horizon on Technitium — `*.hubris.network → 192.168.8.175` (Caddy itself)
- **Caddyfile:** Has 29 `reverse_proxy` directives, all using **hardcoded IP:port**
- **Caddy reload:** Auto-deployed via webhook on git push to `dtoro/caddy-conf`
- **Documentation:** `inventory.yaml` updated, `hosts/*.yaml` stale-before-regenerate
### Why it happened
1. Paperless LXC 103 was **missed** during the 2026-06-02 static-IP migration (Proxmox config still shows `ip=dhcp`)
2. HAOS VM 108 uses DHCP internally (HAOS manages its own network — can't just `pct set`)
3. Both got new IPs from the Technitium `.241.254` pool after a lease renewal
4. Caddyfile still pointed at the old static-range IPs → connection refused
---
## Proposed approach
Three-layer solution:
### Layer 1: Fix the immediate offenders (static assignment)
**Paperless LXC 103:**
- `pct set 103 --net0 name=eth0,bridge=vmbr0,gw=192.168.8.1,hwaddr=BC:24:11:0A:8D:C2,ip=192.168.8.130/24,ip6=auto,type=veth`
- Inside the LXC, update `/etc/network/interfaces` to match
- Reboot/restart networking
**HAOS VM 108:**
- Set a **DHCP reservation** in Technitium for the VM's MAC address, pinning it to `192.168.8.101`
- This avoids needing to reconfigure HAOS internally (which is tedious)
- Alternatively: use `ha network update` from the HAOS console to set a static IP
### Layer 2: Audit and fix all remaining DHCP hosts
Check every LXC/VM hosted on hubris:
```bash
for ct in $(pct list | awk 'NR>1{print $1}'); do
echo "=== CT $ct ==="
pct config $ct | grep "^net0"
done
```
Any with `ip=dhcp` that Caddy reverse-proxies to → convert to static.
**Known candidates to check:**
- CT 102 (nfs-export) — `.200` but not in Caddy. May not need static.
- CT 119 (sophia) — `.157` — is this static or DHCP? Not sure.
- CT 126 (plato) — `.190` — same question.
- VM 100 (zimaos) — `.195` but known to have a stale lease (see 2026-06-03 changelog)
### Layer 3: Add validation
Create a script that runs periodically (cron or homelab cronjob):
**`/opt/homelab-context/scripts/check-caddy-backends.sh`:**
1. Parse `/etc/caddy/Caddyfile` on CT 121 to extract all `reverse_proxy IP:port` targets
2. For each `IP:port`, attempt a TCP connect (timeout 3s)
3. Report any that fail
Could also run as a homelab cron job that notifies dtoro on Matrix if a backend is unreachable.
This catches any future drift proactively (before a user reports it).
### Files likely to change
| File | Change |
|------|--------|
| `inventory.yaml` | May update paperless/HAOS IPs if we choose different static IPs |
| LXC 103 Proxmux config (via `pct set`) | Set static IP |
| Technitium DHCP reservations | Add HAOS reservation |
| `/etc/caddy/Caddyfile` on CT 121 | Already fixed — only changes again if we re-assign paperless IP to `.130` |
| `scripts/check-caddy-backends.sh` | New validation script (new file in homelab-context) |
### Risks / Tradeoffs
- **Pinning paperless to `.130`** — if the LXC was reinstalled since then, `.130` may already be in use. Verify first with `arp-scan` or `nmap`.
- **HAOS static IP via Technitium reservation** vs **inside HAOS**: Technitium reservation is simpler (no HA config changes), but if HAOS's DHCP lease expires and the Technitium server is down, the reservation won't help. A static IP inside HAOS is more robust but requires poking the HA console.
- **Validation script false positives** — a service might be legitimately down for maintenance. The script should be a warning, not an alert.
- **Caddy reload** — each Caddyfile edit triggers an auto-reload via webhook. If the backend is down during reload, Caddy itself stays up (it's just a reverse_proxy target).
### Verification
1. After setting paperless static: `ssh root@192.168.8.175 "curl -s -o /dev/null -w '%{http_code}' http://192.168.8.130:8000"` → 302
2. After Technitium HAOS reservation: `curl -s -o /dev/null -w '%{http_code}' http://192.168.8.101:8123` → 200
3. Run validation script → all targets reachable
4. Confirm from iPhone: both `paperless.hubris.network` and `home.hubris.network` load
### Open questions
1. Should paperless go back to `.130` (its original), or stay at `.243` (current)? Going back to `.130` means updating the Caddyfile again, but keeps the static range allocation consistent.
2. HAOS: Technitium reservation or HAOS-internal static config? Reservation is easier; HAOS-internal is more robust.
3. Should the Caddyfile validation script run as a homelab cron job, or as a cron on the caddy LXC itself?
4. ZimaOS (VM 100) — should we also pin its IP while we're at it?