# REPORT — R-50 island control plane: Phase A artifacts (felhom.eu) (2026-07-25)

Phase A of the R-50 implementation (spike GO). Fresh **appliance** installs are now born on the island
(F1-immune). Pairs with agent **v0.96.0** (which attaches the guest's island net1). byo unchanged.

## Changed here
- `scripts/felhom-host-install.sh` → **v1.19.0**: `ensure_island_bridge()` (portless `vmbr9`,
  `169.254.253.1/30`, idempotent); appliance default binds `local_api` on the island
  (`169.254.253.1:8443`), writes `island_bridge`/`island_guest_addr`, and pins `lan_resolver.host_ip`
  to the LAN IP explicitly (Finding-1 — else moving the bind silently kills LAN DNS). `--no-island`
  opt-out; explicit `--bridge-ip` overrides. Gate `hostinstall_gates.py` ALL PASS.
- `hub/internal/web/configs.go` → `hostInstallVersion` 1.16.0 → **1.19.0** (F-1 sync; clears prior
  drift). Hub CHANGELOG → v0.73.2. Web render test green.

## Determination (A0/A3) — recorded
- **A0 = config-only for the bootstrap endpoint** (`main.go` sets it from `listen_addr`); the version
  bump lives in the agent's net1-attach. The operator chose **agent-bringup** (v0.96.0) over golden-bake
  to eliminate the golden-coupling failure mode.
- **A3 = healer verify-only** — eth0-only (`parseMode` dev-scoped); red-proof test in the agent.
- **net1 deviation from the spike inventory** (it placed net1 in host-install, but host-install doesn't
  create the guest — the agent does) resolved by attaching net1 in the agent at bring-up.

## Coupling / deploy order (important)
An island host-install REQUIRES agent ≥ 0.96.0. **Vouch 0.96.0 before island installs go live**, else a
fresh install writes island config an older agent ignores → guest has no island NIC → broken control
plane. This is the one hard ordering constraint.

## Status of the phases
- **Phase A (artifacts): DONE + committed** (agent `dfd5d73`; this repo this commit). Agent build/publish
  + hub deploy + golden unchanged (net1 comes from the agent, so no re-bake).
- **Phase B (migration): pending** — `RUNBOOK-island-migration.md` + drill migration (B1) + fresh-install
  validation (A4), then demo-hp (B2) and demo-felhom (B3) behind operator go/no-go STOP points.
- **Phase C (Peti cluster): parked** — its own supervised runbook + a new ROADMAP row.