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hyperhive/swarm-controller
Repository files (latest commit first)
Filename Latest commit message Latest commit date
atlas e974194e3a swarm: let an agent publish its own icon
The auth callout grants an agent that presents its own queue credential
one more subject, `$KV.agent-icons.<agent>`: its own key in the
agent-icons bucket and no other. The hive's shared agent client is
granted none of the bucket, since every agent on a hive presents it.

hive-agent writes `/etc/hyperhive/icon.svg`, the file its `GET /icon`
serves, to that key once per start, as a JetStream publish straight to
the subject (what `kv::Store::put` sends, minus the bucket lookup), so
the one subject is the whole grant. No icon deletes the key. A failed
write, including one that arrives before the bucket exists, is retried
with backoff until acked. An agent connected with the hive's shared
client publishes nothing.

swarm-controller creates the bucket as soon as its queue connection is
up, instead of on the first icon read, so an agent's write does not
wait for someone to look.

Measured against a local nats-server with a user allowed publish on
`$KV.agent-icons.atlas` only: the write to its own key is stored and
readable, a write to `$KV.agent-icons.argus` is refused (the ack times
out), the DEL marker makes the key read as absent, and a write before
the bucket exists fails with "no responders".
2026-09-28 13:47:37 +02:00
..
src swarm: let an agent publish its own icon 2026-09-28 13:47:37 +02:00
Cargo.toml swarm-bao: agent certificates issued by a store-generated agent CA 2026-09-27 22:59:27 +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.