fix(backup): HostBackupFailed P1 根治 — Prometheus textfile 指標 + docker socket 讀取

問題一：backup_110_last_success_timestamp 指標從未存在
根因：腳本只寫純文字 last_success 檔，從未輸出 .prom 格式
修復：成功時寫入 /home/ollama/node_exporter_textfiles/backup.prom
      node_exporter 新增 --collector.textfile.directory=/textfile_collector
      volume: /home/ollama/node_exporter_textfiles:/textfile_collector

問題二：Harbor/Gitea rsync 權限拒絕
根因：/var/lib/docker/volumes/ 是 710 root:root，docker group 無法直接存取 FS 路徑
修復：改用 docker run --rm -v <volume>:/source alpine tar czf -
      透過 docker socket（wooo 已在 docker group）讀取 volume 內容再解壓

驗證：備份腳本三項全 OK，node_exporter 9100/metrics 正確輸出指標
      Prometheus absent(backup_110_last_success_timestamp) 應在下次 scrape 後清除

2026-04-18 ogt + Claude Sonnet 4.6

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

scripts/ops/backup-from-110.sh

@@ -27,6 +27,8 @@ set -euo pipefail
 BACKUP_ROOT="${BACKUP_ROOT:-/home/ollama/backup/110}"
 LOG="${BACKUP_ROOT}/backup.log"
 LAST_SUCCESS_FILE="${BACKUP_ROOT}/last_success"
+TEXTFILE_DIR="${TEXTFILE_DIR:-/home/ollama/node_exporter_textfiles}"
+TEXTFILE_PROM="${TEXTFILE_DIR}/backup.prom"
 DATE=$(date +%Y%m%d-%H%M%S)
 ERRORS=0
 
@@ -37,11 +39,14 @@ log() {
 log "=== Starting backup from 110 ==="
 
 # ── Harbor registry data ──────────────────────────────────────────────────────
+# 2026-04-17 ogt: 改用 docker socket 讀取 volumes（/var/lib/docker/volumes/ 是 710 root:root）
+# wooo 是 docker group 成員，可透過 docker run 掛載 volume，不可直接讀取 FS 路徑
 log "Backing up Harbor registry..."
-if rsync -avz --delete \
-    -e "ssh -o StrictHostKeyChecking=accept-new -o ConnectTimeout=10" \
-    wooo@192.168.0.110:/var/lib/docker/volumes/harbor_harbor-data/_data/ \
-    ${BACKUP_ROOT}/harbor/ >> "$LOG" 2>&1; then
+mkdir -p "${BACKUP_ROOT}/harbor"
+if ssh -o StrictHostKeyChecking=accept-new -o ConnectTimeout=10 \
+    wooo@192.168.0.110 \
+    "docker run --rm -v harbor_harbor-data:/source alpine tar czf - -C /source ." \
+    | tar xzf - -C "${BACKUP_ROOT}/harbor/" >> "$LOG" 2>&1; then
     log "✅ Harbor backup OK"
 else
     log "❌ ERROR: Harbor backup failed"
@@ -50,10 +55,11 @@ fi
 
 # ── Gitea repos ───────────────────────────────────────────────────────────────
 log "Backing up Gitea repos..."
-if rsync -avz --delete \
-    -e "ssh -o StrictHostKeyChecking=accept-new -o ConnectTimeout=10" \
-    wooo@192.168.0.110:/var/lib/docker/volumes/gitea_gitea-data/_data/ \
-    ${BACKUP_ROOT}/gitea/ >> "$LOG" 2>&1; then
+mkdir -p "${BACKUP_ROOT}/gitea"
+if ssh -o StrictHostKeyChecking=accept-new -o ConnectTimeout=10 \
+    wooo@192.168.0.110 \
+    "docker run --rm -v gitea_gitea-data:/source alpine tar czf - -C /source ." \
+    | tar xzf - -C "${BACKUP_ROOT}/gitea/" >> "$LOG" 2>&1; then
     log "✅ Gitea backup OK"
 else
     log "❌ ERROR: Gitea backup failed"
@@ -78,9 +84,19 @@ fi
 
 # ── 結果處理 ─────────────────────────────────────────────────────────────────
 if [ "$ERRORS" -eq 0 ]; then
-    # 寫入成功時間戳（供 Prometheus backup_last_success_timestamp 使用）
-    date +%s > "$LAST_SUCCESS_FILE"
-    log "=== Backup completed successfully ==="
+    TS=$(date +%s)
+    # 寫入純文字時間戳（舊格式，保留相容性）
+    echo "$TS" > "$LAST_SUCCESS_FILE"
+    # 寫入 Prometheus textfile 格式（供 node_exporter textfile collector 讀取）
+    # 2026-04-17 ogt: 修復 HostBackupFailed — absent(backup_110_last_success_timestamp) 永遠觸發
+    # 根因：只寫純文字檔，從未輸出 .prom 指標 → node_exporter 找不到 → Prometheus absent()=1
+    mkdir -p "$TEXTFILE_DIR"
+    cat > "$TEXTFILE_PROM" <<EOF
+# HELP backup_110_last_success_timestamp Unix timestamp of last successful backup from 110
+# TYPE backup_110_last_success_timestamp gauge
+backup_110_last_success_timestamp $TS
+EOF
+    log "=== Backup completed successfully (ts=$TS) ==="
     exit 0
 else
     log "=== Backup FAILED ($ERRORS errors) ==="