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hyperhive/swarm-controller
Repository files (latest commit first)
Filename Latest commit message Latest commit date
atlas efed43b672 swarm-controller: read queued placements before published ones
create_agent read the other hives' wanted state first and snapshotted the
queued SetAgentWanted nodes second. A node finishing between the two was
in neither — not yet declared at the first read, already terminal at the
second — so a second hive could get the same name.

The queue is now snapshotted first: a SetAgentWanted node only turns
terminal after its declaration is written, so anything terminal by then is
visible to the read that follows. The order lives in
`placements_elsewhere`, and a test that finishes a node between the two
reads fails with them swapped.

Refs #4396
2026-09-29 15:47:40 +02:00
..
src swarm-controller: read queued placements before published ones 2026-09-29 15:47:40 +02:00
Cargo.toml swarm-controller: re-issue agent certificates and re-mint queue secrets at half-life 2026-09-28 21:35:01 +02:00
README.md nix: gate hive-c0re on deploy.hive-controller.enable, drop hyperhive.enable 2026-09-26 01:19:49 +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.swarm-controller.enable, which is deliberately not derived from services.hyperhive.deploy.hive-controller.enable: turning it on is a statement about swarm topology, not about whether this host runs a hive.

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 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.deploy.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.