# Production

Production runs on two servers of the shared private network: `exch`
(192.168.10.191), the SXCHNGE server, and `infra-gamma` (192.168.10.98), which
keeps the third copy of the data. Each component runs two nodes on `exch` and
one on `infra-gamma`: losing `infra-gamma` keeps the majority, losing one node on
`exch` keeps two of three. Every server runs plain Docker Compose; files are
deployed to `/srv/sxchnge/<component>` on the server.

Ports are published on the private addresses only. Traffic between the servers
is not wrapped in TLS: the network is private and limited by security groups,
and every component authenticates its peers.

## Vault

[#74](https://git.sendico.io/tech/sxchnge/issues/74). Three raft nodes:

| Node | Server | API | Cluster | Compose |
| --- | --- | --- | --- | --- |
| `sxchnge-vault-1` | exch | 192.168.10.191:8200 | :8201 | `vault/exch.yml` |
| `sxchnge-vault-2` | exch | 192.168.10.191:8210 | :8211 | `vault/exch.yml` |
| `sxchnge-vault-3` | infra-gamma | 192.168.10.98:8200 | :8201 | `vault/gamma.yml` |

Containers on `exch` join the Docker network `sxchnge` and use
`http://vault:8200`; the alias belongs to both local nodes. A standby node
forwards requests to the active one, so the leader may be on any server.

Vault is not published to the internet. Its UI is opened through an SSH tunnel
from an administrator's machine, for example
`ssh -N -L 8200:192.168.10.191:8200 exch` and then `http://localhost:8200/ui`.

Nodes unseal themselves with the `transit` seal on the platform Vault
(`https://vault.sendico.io`, key `transit/keys/sxchnge-vault-unseal`). Each server
has its own periodic token in `secrets/transit-token` (root, mode 600, not in Git)
that may only encrypt and decrypt with that key. If the platform Vault is
unreachable while a node starts, the node stays sealed until it is reachable
again; running nodes are not affected. `vault operator init` returns recovery
keys, not unseal keys: they authorize operations such as generating a new root
token but cannot unseal a node. Only the transit key can. Its backup
(`transit/backup/sxchnge-vault-unseal`), the recovery keys and the root token are
kept outside the servers by their holders; see "Platform Vault lost".

`make prod-images` resolves the latest stable Vault release and pins its digest in
ignored `.local/prod/images.env`. All three nodes get the same file: a cluster
runs one build, and an upgrade is a separate rollout of a new file, one node at a
time.

### First rollout

1. On the platform Vault, with an administrator token:

   ```sh
   vault secrets list | grep -q '^transit/' || vault secrets enable transit
   vault write transit/keys/sxchnge-vault-unseal exportable=true allow_plaintext_backup=true
   vault read -field=backup transit/backup/sxchnge-vault-unseal   # store with the holders, then clear the terminal
   vault policy write sxchnge-vault-unseal - <<'EOF'
   path "transit/encrypt/sxchnge-vault-unseal" { capabilities = ["update"] }
   path "transit/decrypt/sxchnge-vault-unseal" { capabilities = ["update"] }
   EOF
   ```

   Create one token per server and write it straight into that server's
   `/srv/sxchnge/vault/secrets/transit-token`, never to a terminal or a log:

   ```sh
   vault token create -orphan -period=768h -policy=sxchnge-vault-unseal \
     -display-name=sxchnge-vault-<server> -field=token
   ```

2. Copy `vault/` and `.local/prod/images.env` to `/srv/sxchnge/vault` on both
   servers.
3. Start the nodes: on `exch`
   `docker compose --env-file images.env -f exch.yml up -d`, on `infra-gamma`
   the same with `gamma.yml`.
4. Initialize once, on `exch`:
   `docker exec -it sxchnge-vault-vault-1-1 vault operator init -recovery-shares=5 -recovery-threshold=3`.
   The output is shown once; store the recovery keys and the root token with
   their holders. Revoke the root token after the bootstrap; a new one is
   generated with the recovery keys when needed.
5. Check: `vault operator raft list-peers` lists three voters; `docker restart`
   of each node in turn unseals it without a person and the raft committed index
   matches on all three.

### Replacing a node

Stop the node, remove it with `vault operator raft remove-peer <node id>`,
delete its volume and start it again: it joins through `retry_join` and copies the
data from the leader. A node keeps its node id and addresses; moving it to
another server is a change of its config file and of every `retry_join` list.

### Platform Vault lost

Running nodes keep working. To start a node without the platform Vault, start
any temporary Vault, enable `transit`, load the stored key backup with
`vault write transit/restore/sxchnge-vault-unseal backup=<backup>`, issue a token
with the policy above, and point `address` in the node configs at that Vault.
Without the key backup the data cannot be unsealed again.