hyperhive/swarm-controller
Repository files (latest commit first)
Filename Latest commit message Latest commit date
atlas 196805bfc0 swarm-controller: retry webhook registration instead of waiting for a restart
Registration ran once at startup and, on failure, deferred to the next
process start. Nothing schedules one, so a controller that lost the boot
race kept running with no hooks registered — and the failure is silent at
both ends, since the forge has nothing to report about a call that never
arrived.

That race is the common case rather than an edge: the controller and the
forge come up together on a rebuild. Measured on a deploy where both
consecutive starts got 502 from the gateway because forgejo was not yet
serving; the forge was healthy two minutes later.

Bounded backoff, not a poll loop — it exists to outlast a slow forge, not
to re-register periodically. Unit ordering would not fix this: the forge
is a remote host in a spread deployment, where no After= can reach it.

Closes #3828
2026-08-31 15:48:42 +02:00
..
src swarm-controller: retry webhook registration instead of waiting for a restart 2026-08-31 15:48:42 +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: give every option an enable, and name the controller one 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.swarm-controller.enable, 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.