Validator Operator

Complete guide for running a Validator on NCN Network.

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Overview

Validators participate in the consensus mechanism by:

• Validating preprocessing requests

• Validating completion results

• Signing consensus messages

• Maintaining network integrity

Earnings: Share of ~5% validator fee per inference

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Requirements

Hardware

Resource	Minimum	Recommended
CPU	2 cores	4 cores
RAM	4 GB	8 GB
Storage	50 GB SSD	100 GB SSD
Network	100 Mbps, low latency	1 Gbps

Capital

• Minimum stake (configurable, check network)

• Gas for registration transactions

Network

• Stable, low-latency connection

• P2P port (8828) accessible

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Setup

1. Install Dependencies

# Update system
sudo apt update && sudo apt upgrade -y

# Install build tools
sudo apt install -y build-essential pkg-config libssl-dev git

# Install Rust
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
source $HOME/.cargo/env

2. Build Registry Node

# Clone repository
git clone https://github.com/neurochainai/ncn-network-v2-rs.git
cd ncn-network-v2-rs

# Build release
cargo build --release -p p2p_registry_node

# Copy binary
sudo cp target/release/p2p_registry_node /usr/local/bin/

3. Generate Validator Key

# Generate new wallet for validation
cast wallet new

# Output:
# Address: 0x...
# Private Key: 0x...

# IMPORTANT: Save this key securely!

4. Stake Tokens (On-Chain)

# Approve tokens for staking
cast send $TOKEN_ADDRESS \
  "approve(address,uint256)" \
  $VALIDATOR_REGISTRY_ADDRESS \
  $STAKE_AMOUNT \
  --private-key $YOUR_KEY \
  --rpc-url $RPC_URL

# Register as validator
cast send $VALIDATOR_REGISTRY_ADDRESS \
  "registerValidator(uint256)" \
  $STAKE_AMOUNT \
  --private-key $YOUR_KEY \
  --rpc-url $RPC_URL

5. Configure Validator

Create /etc/ncn/validator.env:

# Validator Identity
VALIDATOR_PRIVATE_KEY=0x...
VALIDATOR_ADDRESS=0x...

# Network Addresses
GRPC_LISTEN_ADDR=0.0.0.0:50050
P2P_LISTEN_ADDR=/ip4/0.0.0.0/tcp/8828

# Bootstrap Nodes (get from network)
BOOTSTRAP_NODES=/ip4/x.x.x.x/tcp/8828/p2p/12D3KooW...

# Blockchain Configuration
FORKNET_RPC_URL=https://testnet-rpc-1.forknet.io
CHAIN_ID=828
VALIDATOR_REGISTRY_CONTRACT=0x4F11D4cBE08A5aBa052C368C8477412af63a56f3

# Sync Settings
VALIDATOR_SYNC_ENABLED=true
VALIDATOR_SYNC_INTERVAL=60

# Consensus Settings
MIN_VALIDATORS_FOR_CONSENSUS=3

# Logging
RUST_LOG=info

6. Create Systemd Service

Create /etc/systemd/system/ncn-validator.service:

[Unit]
Description=NCN Validator (P2P Registry) Node
After=network.target

[Service]
Type=simple
User=ncn
EnvironmentFile=/etc/ncn/validator.env
ExecStart=/usr/local/bin/p2p_registry_node \
  --grpc-listen-addr ${GRPC_LISTEN_ADDR} \
  --p2p-listen-addr ${P2P_LISTEN_ADDR}
Restart=always
RestartSec=10

[Install]
WantedBy=multi-user.target

7. Start Validator

# Create service user
sudo useradd -r -s /bin/false ncn

# Set permissions
sudo mkdir -p /etc/ncn
sudo chown ncn:ncn /etc/ncn/validator.env
sudo chmod 600 /etc/ncn/validator.env

# Create data directory
sudo mkdir -p /opt/ncn/data
sudo chown ncn:ncn /opt/ncn/data

# Enable and start
sudo systemctl daemon-reload
sudo systemctl enable ncn-validator
sudo systemctl start ncn-validator

# Check status
sudo systemctl status ncn-validator

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Validator Registration Flow

1. Generate validator wallet
          │
          ▼
2. Acquire NCN tokens (testnet faucet or purchase)
          │
          ▼
3. Approve tokens for registry contract
          │
          ▼
4. Call registerValidator() with stake amount
          │
          ▼
5. Start validator node with same private key
          │
          ▼
6. Node syncs with network and joins validator pool
          │
          ▼
7. Start receiving validation requests

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Operations

Monitor Validator

# View logs
sudo journalctl -u ncn-validator -f

# Check peer connections
grep "peer" /var/log/ncn/validator.log

# Check validation activity
grep "validation" /var/log/ncn/validator.log

Check Validator Status

# On-chain status
cast call $VALIDATOR_REGISTRY_CONTRACT \
  "getValidatorInfo(address)" \
  $VALIDATOR_ADDRESS \
  --rpc-url $RPC_URL

# Check if active
cast call $VALIDATOR_REGISTRY_CONTRACT \
  "isActiveValidator(address)" \
  $VALIDATOR_ADDRESS \
  --rpc-url $RPC_URL

View Reputation

# Check reputation score
cast call $VALIDATOR_REGISTRY_CONTRACT \
  "getValidatorReputation(address)" \
  $VALIDATOR_ADDRESS \
  --rpc-url $RPC_URL

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Earnings

Fee Distribution

For each validated inference:

• 5% total goes to validators

• Split among participating validators

• More validations = more earnings

Track Earnings

# Check wallet balance
cast balance $VALIDATOR_ADDRESS --rpc-url $RPC_URL

# View validation count (from logs)
grep "validation successful" /var/log/ncn/validator.log | wc -l

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Reputation System

How Reputation Works

Action	Impact
Successful validation	+1 point
Failed validation	-2 points
Timeout (no response)	-5 points
Slashing event	-20 points

Maintain High Reputation

1. Stay Online: Maximize uptime

2. Fast Response: Low-latency connection

3. Honest Behavior: Never sign invalid results

4. Regular Updates: Keep software current

Check Reputation

# Minimum reputation required
MIN_REPUTATION=20

# Your reputation
cast call $VALIDATOR_REGISTRY_CONTRACT \
  "getValidatorReputation(address)" \
  $VALIDATOR_ADDRESS \
  --rpc-url $RPC_URL

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Avoiding Slashing

Slashable Offenses

Offense	Penalty
Invalid signature	50% stake
Approving invalid result	30% stake
Collusion	100% stake
Prolonged downtime	10% stake

Best Practices

1. Secure Key: Protect validator private key

2. Monitor Health: Set up alerting

3. Redundancy: Consider backup infrastructure

4. Stay Updated: Apply security patches

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Network Participation

Bootstrap Nodes

Connect to existing validators:

# In validator.env
BOOTSTRAP_NODES=/ip4/192.168.1.100/tcp/8828/p2p/12D3KooWA...

Peer Discovery

The P2P network uses Kademlia DHT:

• Automatic peer discovery

• Distributed state replication

• Fault-tolerant messaging

Check Peers

# In logs
grep "Connected to peer" /var/log/ncn/validator.log

# Expected: 5-10+ peers for healthy network

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Maintenance

Update Validator

# Stop service
sudo systemctl stop ncn-validator

# Pull updates
cd ncn-network-v2-rs
git pull

# Rebuild
cargo build --release -p p2p_registry_node

# Update binary
sudo cp target/release/p2p_registry_node /usr/local/bin/

# Restart
sudo systemctl start ncn-validator

Add/Withdraw Stake

# Add more stake
cast send $VALIDATOR_REGISTRY_CONTRACT \
  "addStake(uint256)" \
  $ADDITIONAL_AMOUNT \
  --private-key $YOUR_KEY \
  --rpc-url $RPC_URL

# Withdraw (may have cooldown)
cast send $VALIDATOR_REGISTRY_CONTRACT \
  "withdrawStake(uint256)" \
  $WITHDRAW_AMOUNT \
  --private-key $YOUR_KEY \
  --rpc-url $RPC_URL

Unregister Validator

# Unregister and withdraw all stake
cast send $VALIDATOR_REGISTRY_CONTRACT \
  "unregisterValidator()" \
  --private-key $YOUR_KEY \
  --rpc-url $RPC_URL

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Troubleshooting

"No peers found"

• Check bootstrap nodes are correct

• Verify P2P port (8828) is open

• Check network connectivity

"Consensus failed"

• Not enough validators online

• Check minimum validators setting

• Verify network health

"Slashed"

• Review logs for violation

• May need to add more stake

• Contact community for appeal

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Security Best Practices

1. Secure Validator Key

   • Use HSM for production

   • Never share private key

2. Firewall

   • Only expose necessary ports (8828, 50050)

   • Use fail2ban for brute force protection

3. Monitoring

   • Alert on reputation drops

   • Monitor for slashing events

4. Redundancy

   • Consider backup node

   • Document recovery procedures

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Next Steps

• Monitoring - Set up monitoring

• Troubleshooting - Common issues

• Security - Security documentation