Turn the Beszel-tapped metrics into a self-managing loop.
- migration node_rules (workspace/node-scoped: metric op threshold, for_seconds,
action JSONB, last_fired).
- cm-db: repo/node_rules.rs (CRUD + list_enabled); node_metrics::eval_all merges
Beszel + heartbeat scalars per node + a headroom() heuristic; nodes::status_of;
heartbeat now PRESERVES a `draining` status across heartbeats (so a cordon sticks).
- cm-api: node_rules.rs evaluator (spawn_evaluator, 20s) — when a metric condition
holds for the rule's window it fires drain / undrain / alert (in-memory sustained
+ cooldown tracking, modeled on the node sweeper); routes/beszel.rs rules CRUD
(GET/POST/PATCH/DELETE /api/fleet/rules); spawned in clawmates-server.
- cm-runtime: placement_node() is metrics-aware — a `draining` node stops receiving
new agent sandboxes (falls back to local), so the drain rule is actionable.
- frontend: FleetRules section in the Local view — build rules (node · metric · op ·
threshold · duration → action), toggle/delete, with fired-history.
The loop: hot/overloaded node → rule drains it → placement avoids it → recovers →
undrain rule brings it back. Deployed; node_rules migration applied.
Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>
