docs(backup): record ADR-022; wire into CLAUDE.md, STATUS, TODO
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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@ -89,6 +89,9 @@ Full design rationale: `docs/decisions/`
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- Every **service** role must have a populated `VERIFY.md` (ADR-008/017) — copy `docs/testing/service-verify-template.md`
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- Every **service** role must have a populated `ACCESS.md` (ADR-021) — copy
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`docs/access/service-access-template.md`; rendered from the role's `access__*` data
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- Every **service** role that holds state must have a populated `BACKUP.md` (ADR-022) —
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copy `docs/backup/service-backup-template.md`; rendered from the role's `backup__*`
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data. A stateless service records `backup__state: false` with a reason.
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- One service = one self-contained role; no shared multi-service roles (ADR-004)
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- Role names: `snake_case`, descriptive nouns (`base`, `docker_host`, `reverse_proxy`)
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- Use `make new-role NAME=<name>` to scaffold — never create role structure by hand
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@ -227,6 +230,7 @@ Single-contributor, trunk-based (no merge requests / approval gates):
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| Tagging & run-targeting | `docs/decisions/019-tagging.md` |
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| Firewall strategy | `docs/decisions/020-firewall.md` |
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| Operational access | `docs/decisions/021-operational-access.md` |
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| Backup & disaster recovery | `docs/decisions/022-backup.md` |
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| Adding a new role | `docs/runbooks/new-role.md` |
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| Adding a new host | `docs/runbooks/new-host.md` |
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| Rotating vault secrets | `docs/runbooks/rotate-secrets.md` |
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@ -63,6 +63,8 @@ So `make deploy PLAYBOOK=site` is still incomplete — `base` is only partially
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| `ssh-from-control` firewall source | ADR-021 / ADR-020 | **Built (dormant).** `base__firewall_control_addr` knob + nftables rule + Molecule assertion landed; empty default = no rule until `ubongo`'s LAN address is set in `group_vars`. |
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| `/check-access` verifier | ADR-021 | **Design RESOLVED** (`.claude/commands/check-access.md` authored). **Build pending:** running needs `ubongo` + live/staging hosts + vault. Access analogue of `/verify-service` (ADR-017). |
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| Per-service `ACCESS.md` records | ADR-021 | Template + governance present; per-service files render when each service role is built. |
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| Backup `backup` role + `backup_hosts` group | ADR-022 | Does not exist. Pull node (`fisi`), restic repo, rclone→pCloud, USB air-gap — Plan 2. |
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| Per-service `backup__*` contract + `BACKUP.md` | ADR-022 | Convention defined; inert until service roles exist to declare against. |
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## Keeping this honest
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@ -39,7 +39,10 @@
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7. ~~Define a tagging standard that lets us target runs without over-tagging.~~
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DECIDED (ADR-019): two-tier — role-name tags (auto, at play level) + a closed
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9-tag concern list (`tests/tags.yml`); union-only targeting; enforced by `make lint`.
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8. Ensure the right things are backed up (incl. database dumps if we land on PBS).
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8. ~~Ensure the right things are backed up (incl. database dumps if we land on PBS).~~
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DECIDED (ADR-022): data-only restic (Model A, no PBS) pulled by an off-cluster
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node (`fisi`); per-service `backup__*` + `BACKUP.md`; logical DB dumps; 3-2-1 via
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pCloud + rotated USB air-gap. Build: Plans 2–3.
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9. Decide: a central database server, or individual database services per app?
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10. Should we keep the custom base-container (Molecule test image) method for role testing, or revisit it as boma's testing approach matures (ADR-008)?
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11. ~~Deliberate tagging strategy.~~ DECIDED (ADR-019) — folded into 3.7.
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276
docs/decisions/022-backup.md
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276
docs/decisions/022-backup.md
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@ -0,0 +1,276 @@
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# ADR-022 — Backup & disaster recovery: data-only restic, off-cluster pull node, 3-2-1
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## Status
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Accepted (2026-06-10). Resolves TODO 3.8 ("ensure the right things are backed up,
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incl. DB dumps") and `CAPABILITIES.md` §9 (backup engine / off-site / air-gap, all
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"planned"). Grounds ADR-011's "backup-first" and "snapshot + backup" language, which
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assumed a backup policy existed but never defined one.
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**Doctrine ADR.** It pins the recovery model, backup engine, topology, per-service
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contract, encryption/escrow, restore-testing tiers, retention, alerting, and USB
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air-gap mechanism. It does **not** build any of them — the `backup` role, `fisi`
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node, per-service `backup__*` declarations, and `BACKUP.md` files do not exist yet.
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Designed now, built in the implementation plan referenced at the foot of this ADR.
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## Context
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boma has no defined backup policy. The ADRs assume one exists — ADR-011 makes
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"backup-first" the rule for stateful upgrades and "snapshot + backup" the rollback
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path — but nothing specifies *what* gets backed up, *how* it stays consistent, *where*
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copies live, *how* they are encrypted, or *whether restores actually work*.
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`CAPABILITIES.md` §9 sketches an intent (PBS + restic, pCloud off-site, USB air-gap)
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but commits to nothing.
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The gap is not just theoretical. Every boma service is stateful in some dimension:
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DB contents, bind-mount data dirs, the Vaultwarden vault that holds every secret in
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the stack. Without a backup policy the IaC is not reproducible from nothing; it is
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reproducible-modulo-data. This ADR closes that gap.
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## Decision
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### 1. Recovery model — data-only backups, rebuild from code (Model A)
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boma's *configuration* is reproducible from this repo: Terraform recreates the VM,
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Ansible re-renders the Docker Compose stack. Backups therefore protect **state only** —
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DB contents, bind-mount data dirs, Vaultwarden's vault — not whole-VM images.
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Recovery sequence: Terraform re-provisions the VM → Ansible redeploys → restic
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restores the data. **No Proxmox Backup Server (PBS) in v1.** This keeps the 3-2-1
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topology cheap, fits pCloud's 1 TB comfortably, and turns every restore drill into
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a continuous proof that the IaC *and* the backups both work.
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Trade-off accepted: recovery is slower than a VM-image restore (a full Ansible run
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plus data restore, potentially hours), and it bets the repo is complete enough to
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rebuild from nothing — which Tier-2 restore testing (Decision 8) exists to verify.
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**PBS (Model B) or a per-host hybrid (Model C) can be added later** if real-world RTO
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proves too slow; nothing here precludes it.
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### 2. One backup tier, ~24 h RPO
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A single tier: nightly backup of all state, accepting up to ~24 h of data loss across
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the board. No per-data-type tiering yet — revisit once there is real-world data and
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experience to justify the added machinery.
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### 3. Engine — restic (data) + rclone (off-site); no second encryption layer
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- **restic** captures state into an encrypted, deduplicated repository.
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- **rclone** replicates the repo to pCloud (pCloud has no good headless Linux client;
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rclone has a first-class pCloud backend).
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- restic encrypts the repo at rest, so rclone copies **ciphertext only** — no second
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encryption layer, no pCloud "crypto folder."
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No PBS in v1 (see Decision 1).
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### 4. Topology — central pull node (`fisi`), off the cluster; `backup_hosts` group
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A single backup node owns the canonical restic repo. It is **off the Proxmox cluster**
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— an independent failure domain, so copy 2 survives a PVE node (or the whole cluster)
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dying. This mirrors the existing pattern for `ubongo` (control) and `askari`
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(off-site): a manually-provisioned physical node in its own inventory group, still
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Ansible-managed (the `base` role applies, plus a `backup` role).
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**Pull model.** `fisi` holds SSH keys to each host; per service it runs the declared
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dump command remotely, pulls the declared paths read-only, then `restic` snapshots the
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staged data into its local repo. **Hosts hold no backup credentials and cannot reach
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the repo** — a compromised or ransomwared service host cannot delete backup history.
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**Node assignment:** `fisi` (an HP Elite 600 G9 tower) is penciled in / provisional —
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the *role* ("the backup node") is load-bearing; the physical assignment may be
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revisited when all hardware is on hand. `fisi` holds **2× 8 TB HDDs in a mirror**
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(ZFS or mdraid → 8 TB usable, survives one disk failure). It owns the repo, runs the
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pull orchestration, runs `rclone → pCloud`, and docks the USB air-gap drives
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(Decision 11).
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**Inventory:** a new `backup_hosts` group is added to both inventories, structured
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like `control` and `offsite_hosts`. The `base` role applies.
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### 5. 3-2-1 mapping
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| Copy | Location | Medium | Off-site? | Notes |
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|---|---|---|---|---|
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| 1 | Live data on each host | NVMe/SSD | no | The working data |
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| 2 | `fisi` restic repo | 8 TB HDD mirror | no (on-site, off-cluster) | Canonical repo |
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| 3 | pCloud (via rclone) | Cloud | **yes** | Encrypted ciphertext; **sync-coupled** (see Consequences) |
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| +4 | USB air-gap drive(s) | Removable HDD, **offline** | yes (stored off-site) | The **immutable backstop**; rotated |
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≥3 copies, ≥2 media, ≥1 off-site — 3-2-1 satisfied, with the air-gap drive as a
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fourth, offline copy that no online compromise can reach.
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### 6. Per-service backup contract — `backup__*` data + `BACKUP.md`; governance
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Each service role declares its backup needs in role vars — the same render-from-data
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pattern boma uses for `access__*`/`ACCESS.md` (ADR-021):
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```yaml
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backup__service: nextcloud # identifier; matches the role / compose project
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backup__state: true # false = stateless → no BACKUP.md (pair with a reason)
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backup__paths: # bind-mount dirs / files holding state ([] = none)
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- /srv/nextcloud/data
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backup__dumps: # logical app-consistent dumps ([] = none)
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- cmd: "docker compose -p nextcloud exec -T db pg_dump -U {{ vault.nextcloud.db_user }} nextcloud"
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dest: nextcloud-db.sql
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backup__quiesce: false # true = stop→back up→restart escape hatch (Decision 7 B)
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```
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The pull orchestrator reads these (rendered from inventory) and, per service: SSH in →
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run the dumps → pull the dump files + declared paths read-only → `restic` snapshot. A
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service with **no** `backup__paths` must explicitly declare `backup__state: false` with
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a reason; omission is never an implicit "nothing to back up." (`backup__state` and the
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list-form `backup__dumps` are this ADR's resolution of the spec's open "declared, not
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silent" point.)
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**`BACKUP.md` becomes a required per-service doc** alongside `SECURITY.md`,
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`VERIFY.md`, and `ACCESS.md`, **rendered from the role's `backup__*` data**, documenting:
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what state exists, what is backed up, the dump command, and the per-service restore
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procedure. A template lives at `docs/backup/service-backup-template.md`. Stateless
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services record `backup__state: false` in their vars and note it in `BACKUP.md`.
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**Governance — runbook + gate, not scaffold (consistent with ADR-021).** Three light
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touches mirror how `SECURITY.md`, `VERIFY.md`, and `ACCESS.md` are enforced: the
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service checklist (`docs/security/service-checklist.md`) gains a backup item; the
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`new-role` runbook gains a fill/render/`check-backup` step (copy
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`docs/backup/service-backup-template.md` into `roles/<service>/BACKUP.md` and
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populate the `backup__*` data); and a checklist gate blocks service clearance until
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the record exists and a restore drill confirms it (or a deviation is recorded in
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`accepted-risks.md`). The dormant `/check-backup` verifier is the automated check
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analogue of `/check-access` (ADR-021). **No automated lint script gates `BACKUP.md`
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presence** — same manual-copy-plus-review pattern the sibling records use. The design
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document's "make lint gates its presence" wording is superseded by this governance
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choice.
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### 7. Consistency — logical dumps first; quiesce as escape hatch
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- **Default:** databases are captured with logical dumps (`pg_dump` / `mysqldump`) —
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portable, version-independent, restorable to a fresh DB. Plain data dirs are backed
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up as files. No downtime required.
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- **Escape hatch:** a service whose data cannot be dumped live declares a quiesce step
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(stop container → back up volume → restart) via `backup__quiesce` in the same contract.
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- ZFS/filesystem snapshots are **not** used as the sole DB method (only
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crash-consistent for a live database).
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This is agnostic to the open central-vs-per-app database question (TODO 3.9): either
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way, each service declares how to dump its own data.
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### 8. Restore testing — two tiers; `ubongo` stays bare Debian
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- **Tier 1 — weekly, automated, rolling restore-verify.** Pick the next service in
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rotation, restore its latest snapshot into a throwaway container on `ubongo`
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(reusing the Molecule harness, ADR-015), start the app against the restored data,
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and run that service's `VERIFY.md` checks (ADR-008/017). This catches the failure
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that actually kills people — *silently corrupt or unrestorable backups*. Failures
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alert via ntfy.
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- **Tier 2 — semi-annual full DR rehearsal,** driven from `ubongo` onto PVE staging.
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Rebuild a host from zero via Terraform + Ansible + restic restore on the staging
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cluster. This validates the whole Model-A recovery chain. **At least once a year the
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rehearsal exercises the paper-secret break-glass path** (Decision 10) end-to-end.
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**`ubongo` stays bare Debian, not a hypervisor (ADR-015 unchanged).** Its role is to
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be the independent recovery anchor — "the tool used to rebuild the cluster must not
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live inside the thing it rebuilds." Higher-fidelity real-VM testing is better served
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by the PVE staging environment (same hardware class, same cluster, same provisioning
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path). `ubongo`'s 1 TB NVMe gives ample room for Tier-1 dataset restores; disk
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headroom (not CPU/RAM) is the first thing to watch as data grows (`/capacity-review`).
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### 9. Retention — GFS via restic
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Starting policy: `--keep-daily 7 --keep-weekly 4 --keep-monthly 6 --keep-yearly 1`.
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`restic forget --prune` runs nightly on `fisi`'s repo; pCloud mirrors the pruned repo.
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Tune once real repo growth is observed.
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### 10. Encryption + key escrow + break-glass
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restic encrypts the repo at rest, so **one secret — the restic repo password —
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protects all copies uniformly** (`fisi`, pCloud, USB). One thing to escrow, not three.
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**Escrow locations:**
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- **`fisi`, root-only** (plus in the Ansible vault) — so backups run non-interactively
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and `fisi` is redeployable.
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- **Vaultwarden** — the day-to-day human-accessible copy.
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- **Paper, in a physical safe (off-site)** — the break-glass root of trust; the only
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copy that survives "everything is down."
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**The paper holds *two* secrets:** (1) the **restic repo password** (to read any
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backup at all) and (2) the **Ansible vault master password** (to rebuild hosts from
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the repo — normally from Vaultwarden via `rbw`, which is itself down in a from-zero
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recovery). With both on paper, the break-glass chain has **no circular dependency**:
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paper → restic restores Vaultwarden + repo data → the vault password (from paper)
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drives Terraform/Ansible re-provisioning → services return, `rbw` works again.
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**`mamba` (laptop) is the break-glass clone** (ADR-015): repo + toolchain + mesh +
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`rbw`, with Terraform state synced to it — the rebuild can be driven from `mamba` if
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`ubongo` is also gone. The paper sheet doubles as a short break-glass runbook assuming
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zero running boma infrastructure: install restic on any machine, point it at pCloud
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*or* a USB drive with the password, restore Vaultwarden first, then rebuild with the
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vault password.
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### 11. USB air-gap — plug-and-go cold copy
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A **udev rule on `fisi` matching an allowlist of known drive serials** triggers a
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systemd unit / script that: mounts the drive, confirms it is an expected drive, runs
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**`restic copy` from the local repo → a restic repo on the USB drive** (same
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password → ciphertext if lost/stolen), runs `restic check` on the USB copy, unmounts,
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and **notifies via ntfy** with the result. Only allowlisted serials trigger anything —
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a rogue USB does nothing.
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`restic copy` (not rsync) so the USB is itself a valid restic repo, restorable
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directly in a break-glass with nothing else alive. Drives are rotated and **stored
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off-site** — a second geographic off-site copy independent of pCloud.
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### 12. Failure alerting — guard against silent death
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Success/failure pings alone miss the worst case (*the job silently stopped running*):
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- **Dead-man's-switch:** every successful nightly run pings an **Uptime Kuma push
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monitor**; no ping in ~25 h → alert.
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- **Immediate failure → ntfy** on any job or `predump` error.
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- **Weekly `restic check`** for repo integrity → alert on corruption.
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- **Tier-1 restore-verify failures → ntfy.**
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- *(Later)* emit last-success timestamp + repo size as Prometheus metrics for a
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Grafana panel (fits ADR-018's monitoring direction; not required for v1).
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### 13. Schedule
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- **Nightly backup run (~02:00–04:00),** driven by `fisi` (pull): per host →
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`predump` → pull paths read-only → `restic` snapshot → `restic forget --prune`
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→ `rclone sync` → pCloud. Sequential, off-hours.
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- **Tier-1 restore-verify:** weekly, rolling one service per run, on `ubongo`.
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- **Tier-2 DR rehearsal:** semi-annual on staging; ≥1/year exercises the paper path.
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- **USB air-gap:** manual, approximately monthly, whenever a drive is docked.
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## Consequences
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- boma now has a defined, end-to-end backup policy that closes the gap ADR-011 left
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open; "backup-first" and "snapshot + backup" are no longer assumed.
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- Every service role that holds state must declare its backup contract (`backup__*`
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vars + `BACKUP.md`); stateless services declare `backup__state: false`. Cost:
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per-service declarations and a rendered doc to maintain (mitigated by the new-role
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runbook step + checklist gate).
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- **pCloud is off-site but sync-coupled** — `rclone sync` propagates deletions (a
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prune, or a malicious wipe of `fisi`'s repo, replicates to pCloud). The **USB
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air-gap drive is the only truly immutable copy**; pCloud's own file-version history
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is enabled as a secondary cushion.
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- **`fisi` is the crown-jewel host** — it holds an encrypted copy of all state, so it
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receives full `base` hardening and tight access. restic encryption means a stolen
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`fisi`, USB drive, or pCloud blob yields ciphertext only.
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- **pCloud's 1 TB is the off-site capacity ceiling.** Data-only backups fit for years
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at homelab scale; flag for `/capacity-review` if the repo trends toward ~1 TB.
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- Recovery time under Model A (full Ansible run + data restore) is potentially hours —
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slower than a VM-image restore. PBS/Model B is explicitly deferred, not rejected.
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- The paper break-glass must be kept current (restic password + vault password). An
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outdated paper sheet is the one failure mode this ADR cannot prevent mechanically —
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the semi-annual DR rehearsal is the human control.
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Full design rationale and worked examples: `docs/superpowers/specs/2026-06-10-backup-strategy-design.md`.
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Build path (roles, topology, tests): `docs/superpowers/plans/2026-06-10-backup-strategy.md`.
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## Related
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ADR-002 (security baseline: hardening applied to `fisi`), ADR-004 (one service = one
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role; per-service doc conventions), ADR-008 (testing methodology; Molecule harness
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reused for Tier-1), ADR-011 (update management: backup-first rule now grounded),
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ADR-015 (`ubongo` recovery model; `mamba` break-glass clone; bare-Debian invariant),
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ADR-017 (`VERIFY.md` checks reused in Tier-1 restore-verify), ADR-018 (logging/Alloy
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→ ntfy alerting path), ADR-019 (Proxmox tags; `backup_hosts` group), ADR-021
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(render-from-data pattern: `access__*`/`ACCESS.md` → `backup__*`/`BACKUP.md`;
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runbook+gate governance model).
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@ -115,13 +115,13 @@ render-from-data pattern boma uses for `access__*`/`ACCESS.md` (ADR-021):
|
|||
```yaml
|
||||
backup__paths: # bind-mount dirs / files holding state
|
||||
- /srv/nextcloud/data
|
||||
backup__predump: # optional: command that emits an app-consistent dump
|
||||
cmd: "docker compose exec -T db pg_dump -U {{ ... }} nextcloud"
|
||||
dest: "nextcloud-db.sql"
|
||||
backup__dumps: # logical app-consistent dumps (list; [] = none)
|
||||
- cmd: "docker compose exec -T db pg_dump -U {{ ... }} nextcloud"
|
||||
dest: nextcloud-db.sql
|
||||
```
|
||||
|
||||
The pull orchestrator reads these (rendered from inventory) and, per service: SSH in →
|
||||
run `predump` → pull the dump + declared paths read-only → `restic` snapshot. A
|
||||
run the dumps → pull the dump files + declared paths read-only → `restic` snapshot. A
|
||||
service with **no** `backup__paths` is explicitly "nothing to back up" (declared, not
|
||||
silent).
|
||||
|
||||
|
|
|
|||
Loading…
Add table
Reference in a new issue