thermograph/infra/openbao/README.md

# OpenBao — the secret store, phase 1

**Status: dormant.** Every file here is committed but nothing is cut over. SOPS is
still authoritative for dev, beta and prod, because `TG_SECRETS_BACKEND` defaults to
`sops` for all three in `infra/deploy/env-topology.sh`. Flipping an environment is a
one-line reviewed change, and it should not happen until `verify-parity.sh` passes.

Verified against **OpenBao v2.6.1** (2026-07-22). The binary is `bao`.

---

## Why do this at all

Not for encryption, and not for audit — though the audit log is a real gain. The
decisive reason is one specific failure class that a file-based vault cannot close.

`infra/CLAUDE.md` states the rule: *"vps1 must never hold prod credentials. It's the
box that runs Forgejo, its CI runner, and dev's unreviewed branch — the opposite of an
isolation boundary."*

Today that rule is enforced by a **shell flag** — `THERMOGRAPH_SECRETS_SKIP_COMMON=1`
— set by the *caller*, at three separate call sites (`env-topology.sh:196` →
`deploy.sh:67`, `deploy-dev.sh:86`, `infra-sync.yml:93-95`). The renderer itself does
not know that `env=dev` means never-common. A fourth call site, or one by-hand
`render_thermograph_secrets /opt/thermograph-dev/infra dev`, writes both S3 keypairs
(one read-write on the bucket holding prod's database backups), the VAPID private key
that signs Web Push to real subscribers, `REGISTRY_TOKEN`, and the IndexNow and metrics
tokens onto the CI-runner box — **and exits 0**.

Under `policies/tg-host-dev.hcl` that is not possible to get wrong. dev's identity
cannot read `thermograph/data/common`. A misconfigured caller gets a 403 instead of a
silent success. The failure class is *gone*, not guarded. That is what this migration
buys, and it is worth the cost of running a stateful service.

The estate has already hardened this once by hand (commit `7583258`, "infra-sync:
refuse to render dev's vault onto a host that is not dev"). That is the shape of a
problem that wants an ACL, not another guard.

### What it does *not* buy — stated plainly

- **Rotation of provider-issued credentials.** Roughly half the credential count is
  Discord, Contabo S3, the Forgejo registry token, VAPID, IndexNow. OpenBao cannot
  rotate any of them; they stay static KV entries. Contabo Object Storage is
  S3-compatible but exposes no IAM API, so the AWS secrets engine cannot issue against
  it either.
- **Dynamic database credentials.** Inapplicable here for two independent reasons: the
  apps read `THERMOGRAPH_DATABASE_URL` once at import and hold a pool, so a TTL'd
  credential kills the pool at expiry; and there is no reload path anywhere in the
  codebase — no SIGHUP handler, no config re-read.
- **Better review than git.** This is a real regression. Today a secret change is a
  PR with a diff, backstopped by `secrets-guard` CI. Under OpenBao it is an
  out-of-band API call with no diff and no review. Mitigated by committing a key-name
  manifest so CI can still assert no key vanished, plus the audit log and
  `bao kv metadata` as the change record — but not fully.
- **Fewer moving parts.** SOPS needs no server. This adds a stateful service to keep
  alive, upgrade, back up and TLS-rotate, for ~40 secrets that change rarely.

---

## Shape of the deployment

| Decision | Choice | Why |
|---|---|---|
| Host | **vps2 only** | vps1 must never hold prod credentials, and with a static seal the box also holds the key that decrypts everything. Cost: vps1 needs vps2 up to deploy dev — acceptable, since when vps2 is down prod is down anyway. |
| Process | **native systemd**, not a container | A Swarm service is circular (`deploy-stack.sh` renders secrets to deploy the stack). A plain `docker run` makes the vault depend on the daemon deploys restart, and is one `prune -a` from gone. Native = one dependency, the disk. |
| Storage | **raft**, single node | 2.6.0 **deprecated the `file` backend** for removal in 2.7.0. Raft also has the only backup primitive (`operator raft snapshot save`). A *two*-node raft would be worse than one: quorum of two means losing either node loses writes. |
| Seal | **static auto-unseal** | See below. |
| TLS | self-signed, 10y, on disk | Must **not** come from Caddy/ACME — that would put DNS and the public internet in the boot chain of the secret store. |
| Auth | AppRole per environment, CIDR-bound | 5-minute tokens; secret-ids that only work from the right mesh address. |
| Consumption | keep rendering a dotenv file | Preserves every existing seam and keeps OpenBao a *deploy-time* dependency, never a runtime one. |

### The unseal decision, which is the crux

**Static seal**, key at `/etc/openbao/unseal.key` (0400), plus an off-box copy.

Shamir (`-key-shares=5 -key-threshold=3`) means the vault is sealed after every process
restart — reboot, package upgrade, OOM kill — and a human must type three shares.
`render-secrets.sh` is on the deploy path for all three environments, so a sealed vault
blocks every deploy and every hotfix. With one operator the N-of-M threshold is
theatre: one person holds all the shares, so it buys nothing against the real threat
while costing an availability property the estate has today for free. A Contabo reboot
currently needs no human at all.

OpenBao's docs hedge static seal — *"carefully evaluate"* — but that caveat is aimed at
multi-tenant enterprises. The argument here is that **static seal is not a downgrade
from the status quo**: `/etc/thermograph/age.key` is already one 0400 file per host
that decrypts everything forever with no audit trail. A static seal key is the
identical trust model. What changes is everything layered above it.

**The one new single point of failure:** lose that key and the raft snapshots are
unrestorable. It must exist in ≥2 places, one not on vps2. Hard operator obligation.

A `transit` seal against a second OpenBao on vps1 is genuinely better — vps2's disk
would no longer contain the unseal key — but the vps1 unsealer needs unsealing too, so
the circularity moves rather than dissolves, and it adds "vps1 must be up before vps2's
vault unseals" as a new failure mode. Revisit once the primary migration is boring.

---

## Layout

```
thermograph/data/common          the 16 shared beta+prod values   (= common.yaml)
thermograph/data/env/prod        prod's 16                        (= prod.yaml)
thermograph/data/env/beta        beta's 8                         (= beta.yaml)
thermograph/data/env/dev         dev's 12  — inherits NOTHING     (= dev.yaml)
thermograph/data/centralis/prod  Centralis' 9              (= centralis.prod.yaml)
thermograph/data/ops/backup      S3 creds for ops-cron + the backup age recipient
thermograph/data/legacy/age      the age PRIVATE key — see "the age key survives"
```

Inheritance lives in the render order (`common` then `env/<name>`, last-wins);
isolation lives in the policy. Today both live in one shell variable.

**`centralis/<env>` renders differently from everything above it, and must.** The
app stack's `/etc/thermograph.env` is raw unquoted `KEY=value`; `/etc/centralis.env`
is consumed by `set -a && . /etc/centralis.env`, i.e. bash's full expansion
pipeline, so it is emitted as POSIX single-quoted assignments and then verified by
sourcing it in a clean shell and comparing every value back before the file is
written. `CENTRALIS_TOKENS` is JSON and cannot survive the unquoted form: bash
strips its quotes, Centralis fails closed on the malformed result and serves a
single `shared` identity, which is indistinguishable from the file never having
been written. That is the 2026-07-24 incident, and the round-trip check exists so a
render carrying it cannot reach `/etc`.

Consequence for seeding: `seed-from-sops.sh` applies the raw-dotenv rules (no shell
metacharacters, no newlines) only to `common` and `env/*`. Applying them to
`centralis/*` would reject data that renders perfectly well — the validator matches
the renderer that will consume the path, not a single global rule.

`common` is a top-level path rather than `env/common` on purpose: it makes the dev deny
rule expressible as exactly one path, with no wildcard over `env/*` able to
accidentally re-include it.

**~20 of the 61 keys are not secrets** (`PORT`, `WORKERS`, `APP_CPUS`, `TIMESCALEDB_TAG`,
`THERMOGRAPH_BASE_URL`, the Discord channel IDs, the VAPID *public* key, …). They stay
in the vault **for the cutover**, because byte-identical parity is the entire safety
property and splitting them would destroy it. Moving pure config back into the repo is
a clean follow-on that shrinks the vault-outage blast radius.

---

## The age key survives this migration

**This is the trap that would cause silent data loss.**

`ops-cron.yml:142` and `:197` stream every off-box Postgres and Forgejo dump through
`pg_dump | age -r <recipient> | rclone rcat`, with 30-day S3 retention. Restore uses
`/etc/thermograph/age.key`. So the age keypair is not just the SOPS transport — **it is
the backup encryption key.**

Deleting it along with the SOPS vault files would destroy up to 30 days of database
recoverability, and nothing would notice until someone attempted a restore.

So: keep the age private key at `thermograph/data/legacy/age` *and* in the password
manager, and keep it on disk until either the newest age-encrypted object in S3 has
aged out, or the backup path is re-pointed at a dedicated backup recipient. Retiring
SOPS and retiring age are two different projects.

---

## Runbook

### Stand it up (once, by the operator, on vps2)

```sh
sudo bash infra/openbao/bootstrap.sh          # binary, TLS, seal key, ufw, unit, init
# custody the recovery keys + /etc/openbao/unseal.key OFF the box, then:
export BAO_ADDR=https://127.0.0.1:8200 BAO_CACERT=/etc/thermograph/openbao-ca.crt
export BAO_TOKEN=<root token>
sudo -E bash infra/openbao/bootstrap-policies.sh   # mount, policies, approles
```

> **Do not revoke the root token here.** OpenBao 2.6.0 replaced the unauthenticated
> `/sys/generate-root` with an authenticated `/sys/generate-root-token`
> (HCSEC-2026-08), and `bao operator generate-root` now targets the new one — so
> minting a root token requires a token you already have. **The recovery keys are not
> a way back in**; they rekey, they do not authenticate. Unless
> `disable_unauthed_generate_root_endpoints = false` is set in `config.hcl`, revoking
> the last root token locks you out of an otherwise healthy, unsealed vault, and the
> only remedy is re-initialising from scratch. Revoke only once a second admin
> identity exists.

Use `/etc/thermograph/openbao-ca.crt` (mode `0444`) rather than
`/etc/openbao/tls/bao.crt` — same certificate, but `/etc/openbao/tls/` is `0700
openbao`, so only root can read the latter. Without `BAO_CACERT` every command fails
with `certificate signed by unknown authority`.

### Seed and prove (on vps2 — the age key is already there)

```sh
export SOPS_AGE_KEY_FILE=/etc/thermograph/age.key
infra/openbao/seed-from-sops.sh --dry-run     # key names + counts, writes nothing
infra/openbao/seed-from-sops.sh --all
```

Then prove parity — **not `--all` from one box.** Each AppRole is `secret_id_bound_cidrs`
to the host that legitimately renders it, so an environment can only be verified from
its own host:

```sh
# on vps2
infra/openbao/verify-parity.sh --env prod                          # expect 32 keys
infra/openbao/verify-parity.sh --env beta                          # expect 24 keys
# on vps1
cd /opt/thermograph-dev && infra/openbao/verify-parity.sh --env dev  # expect 12 keys
```

Beta needs no special handling: `env-topology.sh` derives `TG_BAO_APPROLE` per
environment, so beta authenticates as `tg-beta` rather than falling back to prod's
credentials and being denied its own path by `tg-host-prod.hcl`.

`seed-from-sops.sh` reads every production secret in plaintext. Per `infra/CLAUDE.md`
the equivalent `seed-from-live.sh` is explicitly *not for an agent to run*; this
inherits that rule.

### Cut an environment over

One PR per hop, following the estate's own promotion model.

```diff
   dev)
-      TG_SECRETS_BACKEND=sops
+      TG_SECRETS_BACKEND=openbao
```

Order: **dev → beta → prod**, with `verify-parity.sh` green throughout. Recommended
gate before prod: **7 consecutive green parity runs on all three environments**, run
nightly from `ops-cron.yml` over SSH (which gives continuous evidence without granting
CI any vault access).

`TG_SECRETS_BACKEND=sops` remains a working two-way door for the whole period. Keep the
SOPS path for a full release cycle after prod flips — it is the best mitigation
available for anything unforeseen.

### Rollback

Revert the one-line PR and redeploy. The SOPS path is untouched by this work — verified
by rendering dev (12 keys) and prod (32 keys) through it after the dispatch was added,
matching the live hosts exactly.

---

## Failure modes

| Failure | Effect | Mitigation |
|---|---|---|
| Vault down/sealed at deploy | Render returns 1, deploy aborts, **running stack unaffected** — temp-then-install means `/etc/thermograph.env` is never truncated | `Restart=always` + static seal so a reboot self-heals; alert on `/v1/sys/health`; `TG_SECRETS_BACKEND=sops` is a working revert |
| **Audit device wedges** | ⚠️ OpenBao **stops answering requests entirely** when no enabled audit device can record them — a full `/var` on vps2 blocks every deploy | Two devices (file + syslog); logrotate signals **SIGHUP** or bao writes to an unlinked inode; disk alert on vps2 |
| Static seal key lost | Raft snapshots unrestorable | ≥2 copies, one off-box. The one new SPOF |
| Raft corruption / disk loss | Total vault loss | Nightly `operator raft snapshot save`, age-encrypted to S3 beside the DB dumps. **Verify a restore end-to-end before any consumer depends on it** |
| Cold boot of vps2 | Nothing needs the vault | Swarm restarts from persisted specs; `stack.env` / `thermograph.env` / `centralis.env` all persist. **This property exists because we render a file, and would be destroyed by app-native reads** |
| Secret-id leak | Useless off the mesh | `secret_id_bound_cidrs`; revoke by accessor without knowing the value |
| beta credential reaches prod | Cross-env compromise | Separate AppRoles, separate policies, secret-ids owned by the separate deploy users (`agent` vs `deploy`) — a boundary that does **not** exist today, since both currently reach the same root-owned age key. Honest limit: root on vps2 defeats it, exactly as it defeats the single age key now |
| Upgrade to 2.7.0 | Removes the `file` backend and built-in cloud KMS seals | Already avoided by choosing raft + static. Pin the version |

---

## Deliberately out of scope

For ~40 credentials and one operator the real risk is over-engineering. Not adopted:
HA/multi-node raft, namespaces, dynamic database credentials, `bao agent`, cert auth,
PKI, identity groups, transit seal (revisit later), OIDC for the operator.

**OIDC for CI is out of scope for a reason worth recording.** Forgejo Actions *does*
support OIDC — shipped in **Forgejo v15.0**, needing Runner > v12.5.0, enabled via
`enable-openid-connect: true` rather than GitHub's `permissions: id-token: write`. But
this estate runs `codeberg.org/forgejo/forgejo:9-rootless`
(`infra/deploy/forgejo/docker-stack.yml:59`). That is a six-major-version upgrade, and
coupling it to this migration would mean two large independent migrations at once with
no way to tell which one broke. Revisit after Forgejo reaches v15; then
`role_type=jwt` with `bound_claims` removes the last CI-side bearer credential.

CI keeps its SSH keys and `REGISTRY_TOKEN` as Forgejo secrets. **CI gets no vault
access at all** — the SSH-in architecture already means the *host* renders, never the
runner, which is the least-privilege topology and should be preserved rather than
"upgraded".

### Secret zero, honestly

Nothing eliminates it; you choose where it sits and how little of it there is. After
this phase the chain terminates at **9 Forgejo Actions secrets + 1 static seal key + 4
AppRole secret-ids**, versus today's **13 CI secrets + 1 omnipotent age key per host**.

---

## Verification gaps to close on the box

Flagged rather than guessed, because these could not be checked from a workstation:

1. Whether a raft snapshot is restorable under a *different* seal key. Docs don't say.
   **Test in phase 0, before anything depends on it.**
2. Exact `-wrap-ttl` flag spelling on `bao write` — documented in the response-wrapping
   concept page but absent from the commands index. Check `bao write -h`.
3. Debian/Ubuntu package repo URL. The install docs claim `.deb` packages exist but
   give no repository; `bootstrap.sh` uses the GitHub release tarball with checksum
   verification, which is fine and also fixes a standing weakness — `provision-secrets.sh`
   installs sops and age with a bare `sudo curl` and no verification at all.
4. Vault-era naming persists inside OpenBao config (`vault { }` stanza,
   `X-Vault-Wrap-TTL` header). Expect it; don't "fix" it.