Two coupled changes addressing the 2026-05-26 validate-neuron failure
where a fresh deploy of beast had /health unreachable for ~5 minutes
while Qwen3.6-27B q5k materialised, even though systemd reported the
unit as active.
1. main.rs no longer awaits load_default_models before binding axum.
The listener binds first; pre-warm runs in a spawned background
task that holds a read lock on the harness registry for the
duration of its sequential load loop. Concurrent on-demand
/models/load and /v1/chat/completions traffic still flow.
2. /health gains an `activation` field carrying:
state pre_warming | ready
pending model ids queued but not started
in_progress model id currently loading (Option)
completed model ids loaded successfully this activation
failed [{model_id, error}] for failed entries
The field is `#[serde(default)]` so a pre-change cortex polling a
new neuron — or vice versa — keeps working.
`ActivationTracker` (new module `neuron::activation`) owns the
RwLock-wrapped state; load_default_models takes a tracker reference
and updates it per-model. NeuronState holds an Arc clone for the
/health handler.
Tests updated to construct trackers and assert state transitions
(empty noop, two failures → ready with both in `failed`).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Stage 5 of the candle-native pivot. Adds first-class support for
auto-loading a configured set of models when the neuron service
activates.
Config:
- NeuronConfig.default_models: Vec<ModelSpec> (defaults to []).
- neuron.example.toml ships a commented [[default_models]] example.
Activation flow (crates/neuron/src/startup.rs::load_default_models):
- Sequential — VRAM contention makes parallel loads risky.
- Per-entry timing logged at info level on success.
- Failures logged as warnings; the next entry is still attempted.
- An empty list short-circuits without log noise.
Called from main.rs after the registry is built and before the axum
listener binds, so /models reflects the loaded state from the very
first request.
data/neuron.service gains TimeoutStartSec=1800s. With activation
blocked on potentially slow first-time HF downloads + GGUF
materialisation, systemd's default 90s would kill larger model loads
mid-flight.
Two non-gated tests in tests/activation.rs cover the
continues-past-failure and empty-list paths using a synthetically
unknown harness name to fail loads fast without touching the network.
The cuda-integration test from earlier stages still exercises the
real load/unload lifecycle.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
