Nethermind

Installing and configuring Nethermind as a systemd service.

Nethermind

Nethermind is a high-performance Ethereum execution client built on .NET. It is highly favored by validators and MEV searchers due to its optimized execution speeds and flexible configuration.

---

🛡️ Role: Nethermind serves as a direct alternative to Geth. It contributes to Client Diversity, protecting your node (and the network) from potential bugs in the Go-Ethereum codebase.

---

1. Install Nethermind

We recommend installing Nethermind via the official PPA. This ensures you can easily update the node with a simple apt update in the future — just like Geth.

# 1. Install prerequisite (if needed)
sudo apt-get install -y software-properties-common

# 2. Enable the Nethermind PPA
sudo add-apt-repository -y ppa:nethermindeth/nethermind

# 3. Update package lists
sudo apt update

# 4. Install Nethermind
sudo apt install -y nethermind

# 5. Verify installation
nethermind --version

💡 Note: The PPA handles all dependencies (including libsnappy-dev and .NET runtime) automatically.

---

2. Configure Systemd Service

We will configure Nethermind to run as a background service, utilizing the data directories we created in Step 2.

Create the service file:

sudo nano /etc/systemd/system/nethermind.service

Paste the following configuration:

[Unit]
Description=Nethermind Execution Client
After=network.target

[Service]
User=ethereum
Group=ethereum
Type=simple
Restart=always
RestartSec=5

# Execution Command
ExecStart=nethermind \
  --config mainnet \
  --datadir /home/ethereum/execution \
  --JsonRpc.Enabled true \
  --JsonRpc.Host 0.0.0.0 \
  --JsonRpc.Port 8545 \
  --JsonRpc.JwtSecretFile /home/ethereum/jwt/jwt.hex \
  --JsonRpc.EngineHost 127.0.0.1 \
  --JsonRpc.EnginePort 8551 \
  --Network.DiscoveryPort 30303 \
  --HealthChecks.Enabled true

# Resource Limits
LimitNOFILE=65535

[Install]
WantedBy=multi-user.target

🔍 Flag Explanation:

• --config mainnet: Loads the default mainnet presets (Snap Sync, etc.).

• --JsonRpc.JwtSecretFile: The shared secret for the Engine API (Connection to Consensus Client).

• --JsonRpc.Host 0.0.0.0: Allows external access (protected by Firewall).

---

3. Start the Service

Reload the systemd daemon and start the node.

# Reload systemd configuration
sudo systemctl daemon-reload

# Enable Nethermind to start on boot
sudo systemctl enable nethermind

# Start the service
sudo systemctl start nethermind

---

4. Verify Status

Check the logs to ensure Nethermind is running and attempting to peer.

sudo journalctl -fu nethermind

Expected Output:

• Old Blocks: You might see it quickly importing "Old Headers" or "State" via Snap Sync.

• Waiting for CL: You will see messages like Waiting for Consensus Client... or Engine API: New Payload. This confirms it is ready for Step 4.

⚡ Performance Note: Nethermind is very fast at syncing but consumes significant RAM during the initial sync. Ensure your machine has at least 32GB RAM.