CT124 故障復原報告與 CLAUDE.md

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

CLAUDE.md

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+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## What this is
+
+This is **not a software project** — there is no code, build, or test. It is an operations/infrastructure
+notes directory for a self-hosted homelab running **Docker Compose stacks inside Proxmox LXC containers**.
+Files are post-incident / runbook documents written in Traditional Chinese.
+
+Current contents: `CT124_故障復原_20260529.md` — a recovery report for a full Docker/Tailscale outage on host
+CT124 (192.168.42.124, Ubuntu 24.04 LXC) after a hard power-off.
+
+## Working in here
+
+- Documents are the deliverable. "Editing" means writing/revising Markdown, not changing code.
+- Filename convention: `<host>_<topic>_<YYYYMMDD>.md` (e.g. `CT124_故障復原_20260529.md`).
+- Shell snippets in the docs run on the LXC host as root; they are records of what was done, not scripts to
+  execute here. Don't run them against any machine unless explicitly asked.
+- Cross-references point to docs **not in this directory** (e.g. `PVECluster_Architecture.md`'s "停電復電 SOP").
+  If a referenced doc is needed, ask — don't assume it exists locally.
+
+## Key non-obvious fact (CT124)
+
+The outage's original symptom (Tailscale/Headscale offline) was a downstream effect, not the root cause. The
+dependency chain is: **docker daemon → Nginx Proxy Manager container (reverse-proxies :443) → Headscale**.
+External `headscale.lotimmy.com:443` hairpins back to CT124's own WAN IP. When Docker dies, NPM dies, port 443
+stops listening, and the Tailscale client logs out. When debugging Tailscale disconnects on this host, verify
+this chain first before suspecting Tailscale itself.