aitbc/docs/8_development/8_blockchain-node-deployment.md

Blockchain Node Deployment Guide

Prerequisites

• Python 3.11+
• SQLite 3.35+
• 512 MB RAM minimum (1 GB recommended)
• 10 GB disk space

Configuration

All settings via environment variables or .env file:

# Core
CHAIN_ID=ait-devnet
DB_PATH=./data/chain.db
PROPOSER_ID=ait-devnet-proposer
BLOCK_TIME_SECONDS=2

# RPC
RPC_BIND_HOST=0.0.0.0
RPC_BIND_PORT=8080

# Block Production
MAX_BLOCK_SIZE_BYTES=1000000
MAX_TXS_PER_BLOCK=500
MIN_FEE=0

# Mempool
MEMPOOL_BACKEND=database        # "memory" or "database"
MEMPOOL_MAX_SIZE=10000

# Circuit Breaker
CIRCUIT_BREAKER_THRESHOLD=5
CIRCUIT_BREAKER_TIMEOUT=30

# Sync
TRUSTED_PROPOSERS=proposer-a,proposer-b
MAX_REORG_DEPTH=10
SYNC_VALIDATE_SIGNATURES=true

# Gossip
GOSSIP_BACKEND=memory           # "memory" or "broadcast"
GOSSIP_BROADCAST_URL=            # Required for broadcast backend

Installation

cd apps/blockchain-node
pip install -e .

Running

Development

uvicorn aitbc_chain.app:app --host 127.0.0.1 --port 8080 --reload

Production

uvicorn aitbc_chain.app:app \
  --host 0.0.0.0 \
  --port 8080 \
  --workers 1 \
  --timeout-keep-alive 30 \
  --access-log \
  --log-level info

Note: Use --workers 1 because the PoA proposer must run as a single instance.

Systemd Service

[Unit]
Description=AITBC Blockchain Node
After=network.target

[Service]
Type=simple
User=aitbc
WorkingDirectory=/opt/aitbc/apps/blockchain-node
EnvironmentFile=/opt/aitbc/.env
ExecStart=/opt/aitbc/venv/bin/uvicorn aitbc_chain.app:app --host 0.0.0.0 --port 8080 --workers 1
Restart=always
RestartSec=5

[Install]
WantedBy=multi-user.target

Endpoints

Method	Path	Description
GET	/health	Health check
GET	/metrics	Prometheus metrics
GET	/rpc/head	Chain head
GET	/rpc/blocks/{height}	Block by height
GET	/rpc/blocks	Latest blocks
GET	/rpc/tx/{hash}	Transaction by hash
POST	/rpc/sendTx	Submit transaction
POST	/rpc/importBlock	Import block from peer
GET	/rpc/syncStatus	Sync status
POST	/rpc/admin/mintFaucet	Mint devnet funds

Monitoring

Health Check

curl http://localhost:8080/health

Key Metrics

• poa_proposer_running — 1 if proposer is active
• chain_head_height — Current block height
• mempool_size — Pending transactions
• circuit_breaker_state — 0=closed, 1=open
• rpc_requests_total — Total RPC requests
• rpc_rate_limited_total — Rate-limited requests

Alerting Rules (Prometheus)

- alert: ProposerDown
  expr: poa_proposer_running == 0
  for: 1m

- alert: CircuitBreakerOpen
  expr: circuit_breaker_state == 1
  for: 30s

- alert: HighErrorRate
  expr: rate(rpc_server_errors_total[5m]) > 0.1
  for: 2m

Troubleshooting

• Proposer not producing blocks: Check poa_proposer_running metric, review logs for DB errors
• Rate limiting: Increase max_requests in middleware or add IP allowlist
• DB locked: Switch to MEMPOOL_BACKEND=database for separate mempool DB
• Sync failures: Check TRUSTED_PROPOSERS config, verify peer connectivity