Rollup Full Node Setup Guide

Introduction

This guide covers how to set up a full node to run alongside a sequencer node in a Rollkit-based blockchain network. A full node maintains a complete copy of the blockchain and helps validate transactions, improving the network's decentralization and security.

Prerequisites

Before starting, ensure you have:

• A local Data Availability (DA) network node running on port 7980.
• A Rollkit sequencer node running and posting blocks to the DA network.
• The Rollkit CLI installed on your system.

Setting Up Your Full Node

Initialize Chain Config and Copy Genesis File

First, update the config_dir in the rollkit.toml file:

[chain]
  config_dir = "/root/.yourrollupd" // [!code --]
  config_dir = "/root/.yourrollupd_fn" // [!code ++]

Initialize the chain config for the full node, lets call it FullNode and set the chain ID to your rollup chain ID:

rollkit init FullNode --chain-id=your-rollup-chain-id

Copy the genesis file from the sequencer node:

cp /root/.yourrollupd/config/genesis.json /root/.yourrollupd_fn/config/genesis.json

Set Up P2P Connection to Sequencer Node

Identify the sequencer node's P2P address from its logs. It will look similar to:

1:55PM INF listening on address=/ip4/127.0.0.1/tcp/36656/p2p/12D3KooWJbD9TQoMSSSUyfhHMmgVY3LqCjxYFz8wQ92Qa6DAqtmh

Create an environment variable with the P2P address:

export P2P_ID="12D3KooWJbD9TQoMSSSUyfhHMmgVY3LqCjxYFz8wQ92Qa6DAqtmh"

Start the Full Node

Run your full node with the following command:

rollkit start --rollkit.aggregator=false \
  --rollkit.da_address http://127.0.0.1:7980 \
  --rpc.laddr tcp://127.0.0.1:46657 \
  --grpc.address 127.0.0.1:9390 \
  --p2p.seeds $P2P_ID@127.0.0.1:26656 \
  --p2p.laddr "0.0.0.0:46656" \
  --json-rpc.ws-address 127.0.0.1:8547 \
  --api.address tcp://localhost:1318

Key points about this command:

• --rollkit.aggregator=false indicates this is not an aggregator node.
• The ports and addresses are different from the sequencer node to avoid conflicts. Not everything may be necessary for your setup.
• We use the P2P_ID environment variable to set the seed node.

Verifying Full Node Operation

After starting your full node, you should see output similar to:

2:33PM DBG indexed transactions height=1 module=txindex num_txs=0
2:33PM INF block marked as DA included blockHash=7897885B959F52BF0D772E35F8DA638CF8BBC361C819C3FD3E61DCEF5034D1CC blockHeight=5532 module=BlockManager

This output indicates that your full node is successfully connecting to the network and processing blocks.

TIP

If your rollup uses EVM as an execution layar and you see an error like datadir already used by another process, it means you have to remove all the state from rollup data directory (/root/.yourrollup_fn/data/) and specify a different data directory for the EVM client. Preferrably to run a full node on a different machine (or using Docker), as some EVM clients does not have a configurable data directory.

Conclusion

You've now set up a full node running alongside your Rollkit sequencer.