alexion
b87076ebd3
Introduce `modules.network`, the host-level networking foundation a Host declares once. A Host states its trunk interface and the tagged VLAN ids to materialize, and the module emits one systemd-networkd bridge per VLAN, named by the `br-vlan<id>` convention, plus the host's own management address on a chosen VLAN's bridge. The trunk and every bridge set `RequiredForOnline = "no"` so wait-online never blocks boot on a carrier-less link, and the module owns its own NetworkManager `unmanaged` guard so enabling it is self-sufficient. Two assertions tie the management VLAN to the declared VLANs and a management address to a VLAN, so an address can never be silently dropped. Enabled on neogaia as a tracer with placeholder values, proving the host build and bridge-name evaluation through `nix flake check`. No Guest is wired to a bridge yet.
2.3 KiB
spec
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What to build
The host-level networking foundation, modules.network, that a Host declares once and every Guest attaches to.
A Host states its trunk interface and the set of VLANs to materialize, and the Module emits one bridge per tagged VLAN using systemd-networkd, named by the br-vlan<id> convention, and manages the Host's own management address.
This is a standalone host-level Module and does not yet wire any Guest to a bridge — that is the Guest networking placement slice.
Acceptance criteria
modules.networkdeclares anenableoption and its option path mirrors its file location per the Namespace convention.- A Host declares its trunk interface and its set of VLAN ids through the Module's options.
- Enabling the Module emits exactly one systemd-networkd bridge per declared VLAN, each named
br-vlan<id>, and manages the Host's own management address. - A Host enabling
modules.networkbuilds vianix flake check, and the emitted bridge names are verifiable bynix eval.
Implementation Notes
Each VLAN materializes as three networkd entries: a <trunk>.<id> tagged sub-interface stacked on the trunk, a br-vlan<id> bridge, and a network enslaving the sub-interface to the bridge.
The trunk and every bridge set RequiredForOnline = "no", so systemd-networkd-wait-online never blocks boot on a link with no carrier.
The management address takes a static CIDR, or DHCP when left null, on the management VLAN's bridge alone. Two assertions guard it: the management VLAN must be one of the declared VLANs, and a declared management address must name a management VLAN, so an address can never be silently dropped for want of a bridge to carry it.
The Module owns its own NetworkManager unmanaged guard for the trunk, sub-interfaces, and bridges, so enabling it is self-sufficient on a host that also runs NetworkManager rather than pushing that wiring into every Host.
A management.gateway option was considered and dropped as speculative for this slice, since the foundation carries no other routing.
Enabled on neogaia as a tracer with a placeholder trunk and VLAN ids, mirroring the walking-skeleton guest, so the host build and bridge-name evaluation are proven through this host's nix flake check.
No Guest is wired to a bridge — that is the guest networking placement slice.