# ops-bridge Tunnel — cert_command Migration

Date: 2026-06-24  
Workplan: WARDEN-WP-0013 T3  
Catalog: `ops-bridge-tunnel`

Migrate an ops-bridge tunnel from **static SSH keys** to **short-lived warden-signed
certificates** via the `cert_command` contract (`wiki/CertCommandInterface.md`).

ops-warden documents the migration; **ops-bridge** owns tunnel config changes.

---

## Step 0 — Readiness gate (run this first)

Before editing any tunnel config, run the read-only readiness gate (WARDEN-WP-0016).
It confirms ops-warden's side is set — actor inventory, TTL, public key, and (optionally)
host principals — **without signing anything**:

```bash
python scripts/check_tunnel_cert_readiness.py \
  --actor agt-state-hub-bridge \
  --pubkey ~/.ssh/agt-state-hub-bridge_ed25519.pub \
  --config ~/.config/warden/warden.yaml \
  --infra ~/railiance-infra/ansible/inventory/ssh_principals.yaml
```

Exit 0 = ready, 1 = a check failed (fix before proceeding), 2 = bad input. The
Prerequisites and Migration checklist below are the human-readable backing for what the
gate verifies. To additionally prove the `cert_command` contract end to end against a
**local** backend (issues a throwaway cert, validates identity/principals/TTL), add
`--sign-smoke` with a local `warden.yaml`.

---

## Prerequisites

- [ ] Actor registered in `~/.config/warden/inventory.yaml` (see `wiki/ActorInventoryPatterns.md`)
- [ ] Actor keypair on disk (`ssh_key` private, `.pub` for signing)
- [ ] Production `warden.yaml` with `backend: vault` and valid scoped `VAULT_TOKEN`
- [ ] Host trusts warden/OpenBao CA (`railiance-infra` `bootstrap-ssh-ca`)
- [ ] Host principal allows the actor's principals (`railiance-infra` `ssh_principals.yaml`)

---

## Pilot tunnel: `agt-state-hub-bridge`

| Field | Value |
| --- | --- |
| Actor | `agt-state-hub-bridge` |
| Type | `agt` |
| Principals | `agt-task-bridge` |
| TTL | 24 h |
| Private key | `~/.ssh/agt-state-hub-bridge_ed25519` |
| Public key | `~/.ssh/agt-state-hub-bridge_ed25519.pub` |
| cert_command | `warden sign agt-state-hub-bridge --pubkey ~/.ssh/agt-state-hub-bridge_ed25519.pub` |

### Pre-migration smoke (operator workstation)

```bash
export VAULT_TOKEN="<scoped-warden-sign-token>"   # never commit or paste in chat
warden status agt-state-hub-bridge
warden sign agt-state-hub-bridge --pubkey ~/.ssh/agt-state-hub-bridge_ed25519.pub | head -1
```

Confirm exit 0 and cert line starts with `ssh-ed25519-cert-v01@openssh.com`.

---

## Migration checklist

### 1. Inventory and signing path

- [ ] Actor exists: `warden inventory list` shows `agt-state-hub-bridge`
- [ ] `warden sign` succeeds with production OpenBao backend
- [ ] `signatures.log` records the sign (`~/.local/state/warden/signatures.log`)

### 2. ops-bridge tunnel config

Edit `~/.config/bridge/tunnels.yaml` (ops-bridge repo owns schema; example below):

```yaml
tunnels:
  state-hub-coulombcore:
    host: coulombcore
    remote_port: 8001
    local_port: 8000
    ssh_user: agt-state-hub-bridge
    ssh_key: ~/.ssh/agt-state-hub-bridge_ed25519
    actor: agt-state-hub-bridge
    cert_command: "warden sign agt-state-hub-bridge --pubkey ~/.ssh/agt-state-hub-bridge_ed25519.pub"
```

- [ ] `cert_command` uses the **public** key path (warden reads pubkey, writes cert to stdout)
- [ ] `ssh_user` matches the certificate identity / host expectation
- [ ] Remove or disable static-key-only fallback once cert path is verified

### 3. Host-side verification

- [ ] Principal `agt-task-bridge` present in `railiance-infra` `ssh_principals.yaml` for target host
- [ ] Run `scripts/check_principals_drift.py` if inventory `hosts` section documents allowed principals

### 4. Tunnel smoke

```bash
# ops-bridge (from ops-bridge repo)
bridge status state-hub-coulombcore
bridge up state-hub-coulombcore
```

- [ ] Tunnel establishes without static cert file on disk
- [ ] Re-run `bridge up` after cert TTL expires — `cert_command` re-issues automatically

### 5. Policy gate (optional, after FLEX-WP-0007)

When `policy.enabled: true`, confirm `signatures.log` includes `policy_decision_id`
on tunnel-driven signs. See `wiki/PolicyGatedSigning.md`.

---

## Rollback

Keep the static key path until cert_command smoke passes. To roll back:

1. Remove `cert_command` from tunnel config
2. Restore prior static-key or `CertificateFile` workflow
3. Document rollback in ops-bridge session notes (not in git secrets)

---

## Static-key tunnels (legacy)

Tunnels using `agt-claude-*` or other long-lived keys are **out of scope** for this
pilot. Migrate per-tunnel when ops-bridge owner prioritizes them.

---

## See also

- `wiki/CertCommandInterface.md`
- `wiki/OpsWardenConfig.md` — cert_command example
- `wiki/playbooks/operator-openbao-token-hygiene.md`
- `warden route show ops-bridge-tunnel --json`