This guide will walk you through the process of building a node from source, focusing on the op-node and op-geth implementations. These steps are essential if you want to run a node on a specific architecture or inspect the source code of the node you’re running.

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What you’re going to Build

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Rollup Node (op-node)

  • Responsible for deriving L2 block payloads from L1 data and passing those payloads to the Execution Client
  • Analogous to a consensus client in Ethereum

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Execution Client (op-geth)

  • Executes the block payloads it receives from the Rollup Node
  • Exposes the standard JSON-RPC API used by Ethereum developers

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Software Dependencies

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Folder Structure

This guide supports running nodes for arbitrary Gelato RaaS chains, both testnets, and mainnets. Feel free to use any folder structure that suits your needs. For the purposes of this documentation, we will use the following structure:
op-rollup-node/
├── config/
│   ├── testnet/
│   │   ├── genesis.json
│   │   └── rollup.json
│   ├── mainnet/
│   │   ├── genesis.json
│   │   └── rollup.json
├── op-geth/
│   ├── init-geth.sh
│   ├── jwt.txt
│   ├── .env
│   └── ...
├── optimism/
│   ├── jwt.txt
│   ├── .env
│   ├── op-node
│   └── ...
└── jwt.txt

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Create a JWT file

To communicate with op-node and enable the Engine API, you’ll need to generate a JWT secret file and enable Geth’s authenticated RPC endpoint. 
cd /path/to/op-rollup-node
openssl rand -hex 32 > jwt.txt

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Obtain genesis.json and rollup.json

  1. Log in to your Dashboard
  2. Download rollup.json (rollup config) and genesis.json (genesis config) from the details section
  3. Place them in your config/testnet in the op-rollup-node directory
Gelato RaaS Genesis JSON

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Build the Rollup Node

  • Clone the Optimism Monorepo
git clone https://github.com/ethereum-optimism/optimism.git
cd optimism
  • Check Out the Required Release Tag
git checkout ddc37daa49558c2fb5c1a92e694eeb7de5942e00
  • Build op-node
make build

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Build the Execution Client

  • Clone op-geth
git clone https://github.com/ethereum-optimism/op-geth.git
cd op-geth
  • Check Out the Required Release Tag
git checkout 7c2819836018bfe0ca07c4e4955754834ffad4e0
  • Build op-geth
make geth

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Running op-geth

  • Create a Data Directory
cd /path/to/op-rollup-node/op-geth
mkdir data-geth
  • Create a .env File
Create a .env file in the op-geth directory with the following content: 
GENESIS_FILE_PATH="<GENESIS_FILE_PATH>"
SNAPSHOT_FILE_PATH="<SNAPSHOT_FILE_PATH>"
GETH_DATADIR="<DATADIR_PATH>"
GETH_AUTHRPC_ADDR="0.0.0.0"
GETH_AUTHRPC_PORT="<ENGINE_RPC_PORT>"
GETH_AUTHRPC_JWTSECRET="<JWT_FILE_PATH>"
GETH_AUTHRPC_VHOSTS="*"
GETH_METRICS="true"
GETH_METRICS_EXPENSIVE="false"
GETH_METRICS_ADDR="0.0.0.0"
GETH_METRICS_PORT="<METRICS_PORT>"
GETH_GCMODE="archive"
GETH_SYNCMODE="full"
GETH_MAXPEERS="0"
GETH_NODISCOVER="true"
GETH_HTTP="true"
GETH_HTTP_ADDR="0.0.0.0"
GETH_HTTP_PORT="<HTTP_RPC_PORT>"
GETH_HTTP_VHOSTS="*"
GETH_HTTP_CORSDOMAIN="*"
GETH_HTTP_API="web3,debug,eth,txpool,net,engine"
GETH_WS="true"
GETH_WS_ADDR="0.0.0.0"
GETH_WS_PORT="<WS_RPC_PORT>"
GETH_WS_ORIGINS="*"
GETH_WS_API="debug,eth,txpool,net,engine"
GETH_RPC_ALLOW_UNPROTECTED_TXS="false"

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Initialize op-geth

Feel free to customize the base configurations provided in the Optimism documentation to suit your specific requirements. While we will use the recommended configurations for this guide, you can explore and add additional flags as needed. Detailed information about execution layer configurations can be found here.
Create init-geth.sh: 
cd /path/to/op-rollup-node/op-geth
nano init-geth.sh

#!/bin/bash

# Set environment variables
source .env

# Create data directory if it doesn't exist
mkdir -p $DATADIR_PATH

# Initialize geth with the genesis file
echo "Initializing geth with genesis file..."
./build/bin/geth --datadir=$DATADIR_PATH init $GENESIS_PATH

# Generate JWT secret if it doesn't exist
if [ ! -f "$JWT_SECRET_PATH" ]; then
  echo "Generating JWT secret..."
  openssl rand -hex 32 > $JWT_SECRET_PATH
fi

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Run the geth Node

cd /path/to/op-rollup-node/op-geth

# Load environment variables from the .env file in the root directory
source .env

# Initialize geth
./init-geth.sh

# Run the geth command with the environment variables
./build/bin/geth

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Testing the Running Geth Instance

After starting your geth instance, you can test if it’s running and confirm the chain ID: 
curl -X POST http://127.0.0.1:8545 \
-H "Content-Type: application/json" \
--data '{"method":"eth_chainId","params":[],"id":1,"jsonrpc":"2.0"}'
You should see a response similar to this: 
{
  "jsonrpc": "2.0",
  "id": 1,
  "result": "0x2a88" // This is your chain id in hex, in this case its 10888
}

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Running op-node

We will utilize the base configurations provided in the Optimism documentation for the consensus layer. However, you can adjust and expand these configurations to fit your specific requirements. For a comprehensive understanding of all available configurations, refer to the detailed documentation on consensus layer configurations here.

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Create a .env File

Create a .env file in the optimism directory with the following content: 
OP_NODE_L1_ETH_RPC="<L1_RPC>"
OP_NODE_L1_RPC_KIND="standard"
OP_NODE_L2_ENGINE_AUTH="<JWT_FILE_PATH>"
OP_NODE_ROLLUP_LOAD_PROTOCOL_VERSIONS="true"
OP_NODE_ROLLUP_HALT="major"
OP_NODE_ROLLUP_CONFIG="<ROLLUP_JSON_PATH>"
OP_NODE_SEQUENCER_ENABLED="false"
OP_NODE_SEQUENCER_L1_CONFS="5"
OP_NODE_VERIFIER_L1_CONFS="4"
OP_NODE_LOG_FORMAT="json"
OP_NODE_LOG_LEVEL="info"
OP_NODE_P2P_DISABLE="false"
OP_NODE_P2P_LISTEN_IP="0.0.0.0"
OP_NODE_P2P_LISTEN_TCP_PORT="<P2P_TCP_PORT>"
OP_NODE_P2P_LISTEN_UDP_PORT="<P2P_UDP_PORT>"
OP_NODE_P2P_PEER_SCORING="none"
OP_NODE_P2P_PEER_BANNING="false"
OP_NODE_P2P_PEER_BANNING_DURATION="0h1m0s"
OP_NODE_P2P_BOOTNODES="<BOOTNODE_ENR>"
OP_NODE_P2P_ADVERTISE_TCP="<EXTERNAL_P2P_TCP_PORT>"
OP_NODE_P2P_ADVERTISE_UDP="<EXTERNAL_P2P_UDP_PORT>"
OP_NODE_P2P_ADVERTISE_IP="<EXTERNAL_P2P_IP>"
OP_NODE_P2P_SYNC_REQ_RESP="true"
OP_NODE_P2P_STATIC="<STATIC_PEERS>"
OP_NODE_P2P_PRIV_RAW="<P2P_NODE_PRIVATE_KEY>"
OP_NODE_RPC_ADDR="0.0.0.0"
OP_NODE_RPC_PORT="<ROLLUP_RPC_PORT>"
OP_NODE_RPC_ENABLE_ADMIN="true"
OP_NODE_SNAPSHOT_LOG="<SNAPSHOT_LOG_PATH>"
OP_NODE_METRICS_ENABLED="true"
OP_NODE_METRICS_ADDR="0.0.0.0"
OP_NODE_METRICS_PORT="<METRICS_PORT>"
OP_NODE_PPROF_ENABLED="true"
OP_NODE_L1_BEACON="<L1_BEACCON_API_URL>"
OP_NODE_L2_ENGINE_RPC="<GETH_ENGINE_RPC_URL>"
Ensure that op-node P2P ports (<EXTERNAL_P2P_TCP_PORT> and <EXTERNAL_P2P_UDP_PORT>) are accessible externally via <EXTERNAL_P2P_IP>. This allows the node to communicate with other peers on the network.Add the sequencer node’s multiaddr to <STATIC_PEERS> in your configuration. This helps establish a direct connection with the sequencer, ensuring smooth operation and synchronization.

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Run the op-node

cd /path/to/op-rollup-node/optimism

# Load environment variables from the .env file in the root directory
source .env

# Run the op-node command with the environment variables
./op-node/bin/op-node