Add a `group` option to the netpool NixOS module + BOT_BOTTLE_FC_GROUP to
the shell script: when set, the pool's TAP devices are owned by a group
instead of a single user, so any group member can open them (the kernel
lets a TAP's owning-group members attach). This lets an interactive user
and, say, a CI-runner user share one pool. `owner`/`group` are mutually
exclusive (asserted). Single-user `owner` remains the default.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WBMWTEtQdJ4W5UrWuLHCck
The module used `networking.nftables.tables.*` (which forces
`networking.nftables.enable = true`, flipping the host firewall backend)
and `systemd.network.enable` (handing interfaces to systemd-networkd) —
disruptive on an iptables + Docker daily driver.
Rewrite it to a single systemd oneshot that brings the pool up: idempotent
`ip tuntap` for the TAPs + `nft -f` for the independent `inet bot_bottle_fc`
table (its own hooks at priority -10), with ExecStop teardown. Same as the
imperative script, but declarative. It touches neither the firewall backend
nor networkd, so it coexists with iptables/Docker/ufw/firewalld. Verified
through the NixOS module system (service present, firewall untouched).
Drop the now-redundant `render_nixos_module()` paste generator (the module
is a real importable file) and point `backend setup` at importing it (flake
output or the file path), noting it's non-invasive.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WBMWTEtQdJ4W5UrWuLHCck
The default TAP-pool base was 100.64.0.0/10 (RFC-6598 CGNAT) — chosen to
dodge RFC-1918, but that's exactly the range Tailscale assigns node
addresses from, so on a Tailscale host it's the worst pick. Move the
default to 10.243.0.0/16, an obscure RFC-1918 block that steers clear of
docker/libvirt/k8s/LAN and Tailscale.
No default is collision-proof, so add netpool.overlapping_routes(): it
parses `ip -json route show table all` and flags any route intersecting
the pool range (excluding our own bbfc* TAPs and the default route). The
launch preflight warns on overlap; `backend status` reports it.
Distribute the NixOS host setup as a flake module instead of a
copy-pasted blob: nix/firecracker-netpool.nix computes the taps / nft
table from typed options (poolSize, ipBase, ifacePrefix, owner) with a
/31-alignment assertion, and flake.nix exposes it as
nixosModules.firecracker-netpool. Defaults mirror the backend constants;
writeEnvFile emits the matching BOT_BOTTLE_FC_* so the host pool and the
launcher can't drift.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WBMWTEtQdJ4W5UrWuLHCck
didericis