hyperhive/swarm-controller
Repository files (latest commit first)
Filename Latest commit message Latest commit date
atlas 0b7357d4b8 deploy: move the controller and swarm-ui toggles
One commit rather than two because they are not independent: the UI's
`enable` had the controller's as its literal default, so moving the
controller alone would leave the UI's default naming an option that no
longer exists.

The UI keeps that derivation in its new home — it is a view onto the
controller's state and reaches it over that daemon's unix socket, so the
host running the controller is the host that can serve it.

Three spellings had to move together for the UI, not one: the `default`,
the `defaultText` shown in the options doc, and the description prose
that names the old path in words. A grep for the option path finds the
first two.

The sweep also reached outside nix: `swarm-controller`'s crate README and
its `//!` module doc both named the option, as did this repo's own
CLAUDE.md and four pages under docs/. An option's name is API, and its
documentation lives wherever someone thought to write it down.
2026-08-30 04:23:22 +02:00
..
src deploy: move the controller and swarm-ui toggles 2026-08-30 04:23:22 +02:00
Cargo.toml move otel_http_client from swarm-queue-client into swarm-controller 2026-08-29 11:17:24 +02:00
README.md deploy: move the controller and swarm-ui toggles 2026-08-30 04:23:22 +02:00

swarm-controller

The swarm-level daemon. Where hive-c0re owns the agents on one host, this owns what is true across hives — so a swarm runs one of them and most hives leave it off.

Opt-in per host via services.hyperhive.deploy.controller, which is deliberately not derived from services.hyperhive.enable: turning it on is a statement about swarm topology, not about whether hyperhive is installed.

What it does today

Serves one /health endpoint and holds no state.

That is the whole intent of the first slice. The point is to make the unit real — service user, runtime and state directories, socket, nginx reachability — so the swarm-level surfaces that follow have somewhere to land. Inventing those surfaces before they are agreed would bake in a shape nobody chose. See #3066 and the hyperhive.swarm consolidation epic.

Why a unix socket, not a port

The hive-gateway's nginx is the only intended client and reaches the socket through a bind-mount. A listener that is never bound to an address cannot be reached from off-host by mistake.

The socket path is services.hyperhive.swarm.controller.socketPath, default /run/swarm-controller/controller.sock, exported to the process as SWARM_CONTROLLER_SOCKET.

⚠️ The socket's directory is its access control

The socket is 0666. It has to be: nginx runs as a different user and connect(2) needs write. This matches how hive-c0re publishes the per-agent sockets, and rests on the same argument — "the bind source dir is per-agent on host so blast radius is unchanged."

What keeps that safe is that the directory holds one socket. So:

Never point socketPath at a directory that carries anything else. /run/hyperhive above all — it holds host.sock, the host admin socket. Pointing nginx at that directory to reach this socket would put the admin socket within its reach too.

nginx is a host service, so nothing narrows what it can reach except the directory itself — that is the whole of the access control. A unit test pins the default path so a tidying edit fails instead of reviewing cleanly.

RuntimeDirectoryPreserve=yes and the daemon's stale-socket unlink on start are a pair: preserving the directory without the unlink means bind fails with EADDRINUSE after a restart.

Packaging

Built by the workspace derivation and extracted as its own package (nix build .#swarm-controller). Deliberately not in nix/packages' daemonBins — that list is the core stack and drives the bundle services.hyperhive.c0re.package points at, so folding this in would put a swarm-scoped service into every hive's closure.