# vlan50-parent

Creates `enp1s0.50`, a tagged VLAN 50 parent interface on `nik-debian`, for
Multus macvlan/ipvlan attachments (Phase 3/4 of `~/repo/homelab/plan.md`).
Leaves the existing untagged VLAN 40 config (`enp1s0`'s own address,
default route, k3s node identity, host DNS) untouched.

## Before running

- Requires the managed-switch port for `nik-debian` already carrying VLAN
  50 tagged in addition to its existing VLAN 40 untagged/PVID 40 — this is
  the `home-network`-repo-owned switch/Flint handoff from plan.md Phase 1.
  This role has no way to verify that from the host side; if the switch
  isn't actually passing tagged VLAN 50 frames yet, the subinterface will
  come up with link state but no VLAN 50 traffic will ever arrive.
- Confirm console/recovery access to `nik-debian` (physical/IPMI/other
  out-of-band) before applying, same as any host networking change.

## What it does

- Installs the `vlan` package and loads/persists the `8021q` kernel
  module.
- Writes `/etc/network/interfaces.d/enp1s0.50` — `iface ... inet manual`
  with `vlan-raw-device enp1s0` and `vlan-id 50`. No IP address is ever
  assigned to it.
- Brings the interface up now (`ifup`) if not already present, and
  asserts afterward that it's UP, carries no IPv4/IPv6 address, and that
  the host's own default route is still via `enp1s0` — never via
  `enp1s0.50`.

## Rollback

```bash
sudo ifdown enp1s0.50 || true
sudo ip link delete enp1s0.50 2>/dev/null || true
sudo rm -f /etc/network/interfaces.d/enp1s0.50
sudo rm -f /etc/modules-load.d/8021q.conf
```

Leaves the `vlan` package and `8021q` module load itself in place (harmless
if unused); remove manually only if desired.