docs: document broker-mediated cluster architecture, coordinator vs worker node types

Developer-Architecture.md (§6):
  - Broker-mediated design model as preferred architecture
  - Coordinator vs Worker node type table with full service requirements
  - Service distribution ASCII diagram
  - Workers connect as AMQP clients only (no local broker needed)
  - Contrasted with service-mesh alternative

docker.md (§9):
  - New Worker Node Deployment Model section
  - Worker requirements: llama-server binary + node_agent.py + aio-pika
  - Explicit table of what workers do NOT run
  - Architecture note: broker-mediated vs service-mesh
  - Ref: AMQP-0-9-1 client-server protocol since 2006
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└─────────────────────────────────────────────────────────┘
```
> **This compose stack defines the coordinator.** A coordinator runs jC, the broker, and optional infrastructure services. Workers (headless inference nodes) do not use Docker — they install just llama-server + a Python node agent. See §12 for the worker deployment model.
### Service roles
| Service | Image | Role |
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| **LLM model download** | HuggingFace CLI integration in setup.sh, or manual download. Manual is simpler. | Low |
| **Dockerfile optimization** | Pin pip hashes, use `--no-cache-dir`, consider `slim` vs `alpine`. Alpine has musl compatibility issues with psutil. Stay with slim. | Medium |
## 9. Checklist (pre-v1.0 gate)
## 9. Worker Node Deployment Model
The Docker stack above defines the **coordinator** only. Workers (headless inference nodes) have a radically lighter footprint.
### 9.1 What a worker runs
```
Worker machine (e.g. jarvis, Corsair)
┌────────────────────────────────────┐
│ llama-server │
│ (single binary, no build needed) │
│ │
│ node_agent.py │
│ (Python script, aio-pika client) │
│ ─ connects to coordinator's RMQ │
│ ─ publishes heartbeat + reg │
│ ─ consumes model_swap commands │
│ │
│ ROCm or CUDA runtime (if GPU) │
└────────────────────────────────────┘
```
### 9.2 What a worker does NOT run
| Service | Reason |
|---------|--------|
| RabbitMQ server | Connects as AMQP *client* only (aio-pika) |
| FastAPI / uvicorn / jC | No HTTP API, no UI, no database |
| SQLite | No persistent state of its own |
| SearXNG | No web search needs |
| Qdrant | No local vector store |
| Ollama | Uses coordinator's embedding endpoint |
| Docker | Everything runs as bare binaries |
| Python venv with full jC deps | Only needs `aio-pika` + `httpx` |
### 9.3 Worker setup
```bash
# Install llama-server binary
wget https://github.com/ggml-org/llama.cpp/releases/.../llama-server
chmod +x llama-server
# Install node agent deps
pip install aio-pika httpx
# Create node agent script (from repo: tools/node_agent.py)
# Configure COORDINATOR_AMQP_URL in environment
```
### 9.4 Multiple workers
Each worker registers independently with the coordinator's RabbitMQ. The coordinator tracks all registered workers via `CLUSTER_NODES` and routes inference requests to the best-matching node based on classification and availability.
### 9.5 RabbitMQ and workers — architecture note
Workers connect to RabbitMQ as **standard AMQP TCP clients** — no broker software required. The AMQP-0-9-1 protocol has always been client-server (since 2006), and libraries like `aio-pika`, `pika`, `amqplib`, `php-amqplib`, etc. connect over a single persistent socket. This is distinct from a service-mesh design where every node runs the same software stack and role is determined by config.
```
Broker-mediated model (this project):
Coordinator runs RabbitMQ broker ←── Workers connect as AMQP clients
Service-mesh model (alternative):
Every node runs RabbitMQ broker ←── Nodes cluster together, all autonomous
```
The broker-mediated model is the preferred architecture for this project because workers are intentionally heterogeneous (different GPUs, different models, ARM vs x86) and should not be burdened with infrastructure services.
## 10. Checklist (pre-v1.0 gate)
- [ ] `Dockerfile` written and builds clean
- [ ] `docker-compose.yml` boots all containers
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---
## 10. Files to create for B3
## 11. Files to create for B3
```
docker.md ← this file (planning doc)
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`POST /api/rag/flush` (admin required) — deletes all non-pinned vectors. Returns `{deleted_count, collection, status}`.
## 6. AMQP Cluster Architecture (WIP)
## 6. Cluster Architecture
RabbitMQ on ultron with dedicated `jarvischat` vhost:
### 6.1 Design Model: Broker-Mediated
JarvisChat uses a **broker-mediated** cluster design. This is the preferred architecture and is reflected in all implementation decisions below.
**How it works:**
- A single RabbitMQ broker (or clustered set of brokers) acts as the central nervous system
- **Coordinator nodes** run the FastAPI app, host the HTTP API/UI, and publish commands to the broker
- **Worker nodes** connect as AMQP *clients only* — they consume commands and publish status events, but run no broker software themselves
- Communication is asynchronous and persistent: each node opens a TCP connection on startup and keeps it alive. The AMQP-0-9-1 heartbeat detects silent failures within ~60s.
**Why broker-mediated:**
- Workers are heterogeneous (different GPUs, different models, ARM vs x86) — no assumption of uniform software
- Workers are lightweight — a Raspberry Pi with a USB AI accelerator can participate without running a broker
- The coordinator delegates work via messages, not by SSH'ing into workers or requiring shared filesystems
- Failure is isolated: a crashed worker drops off the heartbeat list; the coordinator reassigns its work
**What it is NOT:**
- Not a service mesh — workers do not run identical software stacks
- Not autonomous failover — if the coordinator dies, a replacement must be manually promoted (or pre-configured as a secondary coordinator). Workers cannot self-promote to coordinator because they lack the required services (FastAPI, SQLite, DB schema, SearXNG, Qdrant, etc.)
- Not a peer-to-peer cluster — all orchestration flows through the coordinator
### 6.2 Node Types
Every physical machine in the cluster is classified by which services it runs. Two node types are defined:
| Aspect | Coordinator | Worker |
|--------|------------|--------|
| **Role** | Serves HTTP API/UI, orchestrates inference, owns cluster state | Runs inference models on behalf of the coordinator |
| **Python** | Required — runs FastAPI app | Required — runs node agent (aio-pika consumer) |
| **RabbitMQ server** | Required — hosts the broker | Not required — connects as AMQP client only |
| **RabbitMQ client (aio-pika)** | Required — publishes commands, consumes events | Required — consumes commands, publishes events |
| **FastAPI / uvicorn** | Required | Not needed |
| **SQLite** | Required — owns jarvischat.db | Not needed |
| **Qdrant** | Optional (recommended) — vector DB for RAG | Not needed |
| **SearXNG** | Optional — web search | Not needed |
| **llama-server** | Optional — can share its own GPU for inference | Required — this is why the worker exists |
| **Ollama** | Optional — embeddings for RAG | Not needed |
| **rocm-smi / nvidia-smi** | Optional — hardware stats | Optional — node agent reports this at registration |
### 6.3 Service Distribution Summary
```
Coordinator Worker(s)
┌────────────────────┐ ┌─────────────────────────┐
│ jarvisChat │ │ llama-server │
│ (FastAPI + SQLite)│ │ (inference) │
│ RabbitMQ server │◄──AMQP───────│ aio-pika (agent) │
│ SearXNG (opt) │ persistent │ ROCm / CUDA (if GPU) │
│ Qdrant (opt) │ TCP │ │
│ Ollama (opt) │ conn │ No broker │
│ llama-server(opt) │ │ No jC │
└────────────────────┘ │ No DB │
│ No search/vector │
└─────────────────────────┘
```
### 6.4 RabbitMQ Topology
Every RabbitMQ server belongs to a cluster. Currently only the coordinator runs one; if high availability is needed, additional nodes can join the RMQ cluster without changing the architecture.
| Exchange | Type | Purpose |
|----------|------|---------|