felhom.eu/documentation/runbooks/RUNBOOK-hub-db-offsite-backup.md

Runbook — the hub database in a backup that is NOT on DooPlex (R-173, R-232) — PROPOSED, needs the operator's go

Status: PROPOSED 2026-10-05. Nothing here has been done. DooPlex and ep0 are protected; every step below changes one of them, so each waits for the operator's go (the decision is in STATUS.md). The readings this plan rests on: audits/hub-safety-2026-10-05/partC/readings.txt (read only).

1. What is true today (measured 2026-10-05)

Question	Answer
Where the hub database lives	/data/hub.db (+ -wal, -shm) in the hub pod, PVC hub-data (Longhorn, 1 Gi, replicas on DooPlex's sdb1). 357 MiB.
Is it in a backup?	Yes, but only on DooPlex. Longhorn's backup-daily (04:00) and backup-weekly (Sun 05:00), retain=1, write to nfs://192.168.0.180:/mnt/5_hdd/backup/longhorn-pvc — DooPlex's own sda1. Last: 2026-10-05 02:06 UTC, Completed.
Why R-173 said "excluded"	The PVC carries recurring-job-group.longhorn.io/default: disabled (git, manifests/hub.yaml, commit 868e8465 of 2026-02-16, no reason given). The live Longhorn Volume carries enabled — set by hand at some point, so the backups run. This is drift: the PVC label is the source of truth (Longhorn syncs PVC → Volume), so the backups can stop at any sync without anyone seeing it.
What DooPlex's own backup covers	dooplex-backup.timer (03:19): k3s state, k8s Secrets (GPG files), Gitea mirrors, user data, PostgreSQL dumps — all onto sda1, the same machine. Nothing leaves DooPlex (audits/RECON-dooplex-backup-2026-08-06.md, R-232).
What tells anyone a backup failed	Nothing. NOTIFY_WEBHOOK_URL is commented out, so notify_failure is a no-op. No Prometheus rule watches a Longhorn backup's success or age, nor dooplex-backup.service.
What the database holds	Box→hub API keys, customer configs (incl. the owner passphrase), escrow custody blobs (opaque), the PBS-DR token values, the off-site sub-account passwords and — since hub v0.135.0 — the console passwords sealed under OFFSITE_SECRET_KEY.
What a copy is worth without the key	The sealed columns (console passwords, off-site passwords) are useless without OFFSITE_SECRET_KEY. The key lives only in Secret/offsite-secret-key on DooPlex (and in the GPG secrets export on the same disk). A backup off DooPlex without a key off DooPlex restores a hub that cannot open any console password.

2. The plan (option A — my pick): a nightly, encrypted, consistent copy on ep0's PBS

ep0 is already off-site (Hetzner), already runs PBS, and DooPlex already reaches it through felhom-ep0-pbs-tunnel (127.0.0.1:18007). ep0's datastore is also pulled back to DooPlex nightly (ep0-copy), so the copy exists in two places, one of them off DooPlex. The copy is encrypted on DooPlex with a key ep0 never sees.

Step 0 — the keys go off DooPlex first (operator, at the keyboard, 5 min)

Without these, every later step backs up something nobody can open after a DooPlex loss.

# 1. the hub's seal key → the operator's password manager (never a file, never a chat)
sudo kubectl -n felhom-system get secret offsite-secret-key -o jsonpath='{.data.OFFSITE_SECRET_KEY}' | base64 -d; echo
# 2. (after Step 2) the backup encryption key's paper copy → the password manager
sudo proxmox-backup-client key paperkey /etc/felhom-hub-backup/enc.key --output-format text

Step 1 — end the label drift (CC, a felhom.eu commit + ArgoCD sync; reversible)

manifests/hub.yaml: recurring-job-group.longhorn.io/default: disabled → enabled. Sync. Check: sudo kubectl -n felhom-system get pvc hub-data -o jsonpath='{.metadata.labels}' and the Volume label both read enabled. This keeps today's on-DooPlex copy alive; it is not the off-site copy.

Step 2 — a write-only place on ep0 (on ep0, root; the operator's go for an ep0 change)

proxmox-backup-manager user create dooplex-hub@pbs --comment "DooPlex pushes the hub DB (R-173)"
proxmox-backup-manager user generate-token dooplex-hub@pbs push      # the secret → a 0600 file on DooPlex, file → file
# namespace for operator data, apart from the households' namespaces
proxmox-backup-client namespace create operator --repository 'root@pam@127.0.0.1:8007:felhom-offsite'
proxmox-backup-manager acl update /datastore/felhom-offsite/operator DatastoreBackup --auth-id 'dooplex-hub@pbs!push'
# retention on ep0 (the server prunes; the pushing token cannot delete — DatastoreBackup has no Prune)
proxmox-backup-manager prune-job create prune-operator-hubdb --store felhom-offsite --ns operator \
  --schedule 'daily 03:45' --keep-daily 14 --keep-weekly 8

Step 3 — a consistent snapshot of the live database (CC, a hub release)

hub.db is in WAL mode and is written every few seconds; copying the three files is not one point in time. The hub gets a nightly VACUUM INTO '/data/snapshots/hub-<UTC date>.db' (keeps 2, logs size and duration) — one SQLite statement, consistent by construction, WAL-aware. Needs a hub release (filed under R-173). No sqlite3 exists in the hub image, so the copy must be made by the hub itself.

Step 4 — the push (on DooPlex, root; felhom-hub-db-backup.service + .timer 02:30, CC writes, operator approves)

#!/bin/sh -eu
# /usr/local/sbin/felhom-hub-db-backup — push the newest hub snapshot to ep0 (R-173). Root, 0755.
STAGE=/var/lib/felhom-hub-backup/stage; mkdir -p "$STAGE"; chmod 700 "$STAGE"
SNAP=$(kubectl -n felhom-system exec deploy/hub -- sh -c 'ls -1t /data/snapshots/hub-*.db | head -1')
kubectl -n felhom-system exec deploy/hub -- cat "$SNAP" > "$STAGE/hub.db"
sqlite3 -readonly "$STAGE/hub.db" 'PRAGMA integrity_check' | grep -qx ok          # never push a broken copy
export PBS_PASSWORD_FILE=/etc/felhom-hub-backup/token PBS_FINGERPRINT=<ep0 cert fingerprint, as in ep0-datastore-copy.md>
proxmox-backup-client backup hubdb.pxar:"$STAGE" --ns operator --backup-id dooplex-hub \
  --keyfile /etc/felhom-hub-backup/enc.key --repository 'dooplex-hub@pbs!push@127.0.0.1:18007:felhom-offsite'
shred -u "$STAGE/hub.db"
# the positive signal the alarm reads (written ONLY on success):
echo "felhom_hub_db_backup_last_success_timestamp_seconds $(date +%s)" > /var/lib/node_exporter/textfile_collector/felhom_hub_db.prom.$$ \
  && mv /var/lib/node_exporter/textfile_collector/felhom_hub_db.prom.$$ /var/lib/node_exporter/textfile_collector/felhom_hub_db.prom

Step 5 — the restore test (weekly, Sun 04:30, same unit family)

T=$(mktemp -d); chmod 700 "$T"
proxmox-backup-client restore "host/dooplex-hub/$(newest snapshot)" hubdb.pxar "$T" --ns operator \
  --keyfile /etc/felhom-hub-backup/enc.key --repository 'dooplex-hub@pbs!push@127.0.0.1:18007:felhom-offsite'
sqlite3 -readonly "$T/hub.db" 'PRAGMA integrity_check' | grep -qx ok
test "$(sqlite3 -readonly "$T/hub.db" 'SELECT COUNT(*) FROM hosts')" -gt 0
test "$(sqlite3 -readonly "$T/hub.db" "SELECT COUNT(*) FROM host_recovery WHERE secret NOT LIKE 'enc:v1:%'")" -eq 0
shred -u "$T/hub.db"*; rmdir "$T"
echo "felhom_hub_db_restore_test_last_success_timestamp_seconds $(date +%s)" > …/felhom_hub_db_restore.prom   # same tmp+mv

The push token needs DatastoreReader on operator too for the restore (or a second, read-only token — cleaner).

Step 6 — the alarm (homelab-manifests prometheus-rules, then POST /-/reload — the Prometheus there has no reloader)

- alert: HubDBBackupStale
  expr: time() - felhom_hub_db_backup_last_success_timestamp_seconds > 26*3600 or absent(felhom_hub_db_backup_last_success_timestamp_seconds)
  for: 30m
  labels: {severity: critical}
  annotations: {summary: "The hub database has not reached ep0 for 26 h (R-173)"}
- alert: HubDBRestoreTestStale
  expr: time() - felhom_hub_db_restore_test_last_success_timestamp_seconds > 8*24*3600 or absent(felhom_hub_db_restore_test_last_success_timestamp_seconds)
  for: 1h
  labels: {severity: warning}

Both reach the existing email-notifications receiver. absent() makes "the script never ran" an alarm too — an empty log is not a success.

Step 7 — prove it once (CC, with the operator's go)

Run the unit by hand; read the snapshot on ep0 (proxmox-backup-client snapshot list --ns operator); run the restore test by hand; stop the timer for a day on purpose and see HubDBBackupStale mail arrive (positive observable), then start it again.

3. Bringing the hub back from this copy (the procedure the plan exists for)

1. A k3s with the felhom ArgoCD app, and Secret/offsite-secret-key recreated with the SAME value (Step 0 copy).
2. Restore the newest snapshot (Step 5's first command, with the paper key), scale deploy/hub to 0, copy hub.db into the PVC (no -wal/-shm — the snapshot is a whole database), scale to 1. The log line console passwords sealed at rest (0 legacy plaintext row(s) sealed now) and a working reveal prove the key matches.

4. Option B (not my pick): restic to a dedicated Hetzner Storage Box sub-account

Same Steps 0, 1, 3, 5, 6; the push is restic backup to a new sub-account with the R-820 append-only key pin. Costs a new sub-account and its own key custody; the Storage Box sub-account shell can rm (memory: storagebox-subaccount-shell) unless the pin is right. ep0 already has the server-side prune and the return copy, so A is less new machinery.