# base

Hardened baseline applied to every boma host. Built incrementally; the first concern
implemented is the **host firewall** (`firewall` tag).

## Firewall (nftables)

Default-deny inbound + east-west allowlisting + permissive egress, per ADR-020. Rules
are rendered from the shared `firewall_catalog` / `firewall_zones` (in `group_vars/all`)
by the `resolve_firewall_rules` filter, written to `/etc/nftables.conf`, syntax-checked
with `nft -c` at render time, and applied with an **auto-rollback safety net**
(`systemd-run` arms a revert that a follow-up task cancels once connectivity is
confirmed). The apply sequence lives in tasks rather than a handler so the confirm/cancel
step is controllable.

`/etc/nftables.d/*.nft` is `include`d by the ruleset — the extension hook the
`docker_host` role uses for container forward/NAT rules.

### Variables
See `defaults/main.yml` (`base__firewall_*`). SSH is accepted only on
`base__firewall_mgmt_interface` (default `wt0`, the NetBird overlay — ADR-016); set it to
a reachable interface/source until NetBird is built. Set `base__firewall_apply: false` to
render + validate without applying (used by Molecule).

### Testing
- `tests/test_firewall_rules.py` — pytest units for the resolver.
- `make test ROLE=base` — Molecule renders + `nft -c` syntax-checks (never applies; it
  shares the host kernel). Enforcement + the apply/rollback path are verified at ADR-008
  Level 2 on staging VMs.

## Mesh enrollment (NetBird agent)

Enrols the host as a NetBird *agent* on the self-hosted mesh (ADR-016): installs the
pinned `netbird` daemon from the upstream APT repo (keyring in `/etc/apt/keyrings`,
mirroring the `docker_host` repo idiom) and runs `netbird up` against the coordinator
with a setup key. Tagged `mesh`.

**Additive only — this concern makes no firewall change.** SSH is already gated to the
NetBird overlay interface by the `firewall` concern (`base__firewall_mgmt_interface`,
default `wt0`); enrolling a host simply brings that interface up. No port is opened here.

Enrolment is **opt-in**: `base__mesh_enabled` defaults to `false`, so applying `base` to
a host not on the mesh is a no-op for this concern. Re-enrolment is guarded on
`netbird status` reporting `Management: Connected`, so re-runs are idempotent. The setup
key is sourced from `vault.netbird.setup_key` and passed with `no_log` (it lands on the
process argv).

### Variables

| Variable                     | Default                              | Purpose |
|------------------------------|--------------------------------------|---------|
| `base__mesh_enabled`         | `false`                              | Opt-in switch — include the concern at all. Set per-host/group to enrol. |
| `base__mesh_manage`          | `true`                               | Test gate — when `false`, skips the live network/daemon tasks (apt install, status check, `netbird up`) so Molecule can exercise the wiring without a coordinator. |
| `base__mesh_management_url`  | `https://netbird.askari.wingu.me`    | Coordinator (management) URL. |
| `base__mesh_setup_key`       | `{{ vault.netbird.setup_key }}`      | Enrolment setup key, from vault. |
| `base__mesh_version`         | `"0.72.4"`                           | Pinned agent version (matches the coordinator). The exact apt version string is confirmed on-host at deploy. |