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 ++]

Let's set a terminal variable for the chain ID.

CHAIN_ID=gm

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=$CHAIN_ID

Copy the genesis file from the sequencer node:

cp $HOME/.$CHAIN_ID/config/genesis.json $HOME/.${CHAIN_ID}_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

We are now ready to run our full node. If we are running the full node on the same machine as the sequencer, we need to make sure we update the ports to avoid conflicts.

Make sure to include these flags with your start command:

  --rpc.laddr tcp://127.0.0.1:46657 \
  --grpc.address 127.0.0.1:9390 \
  --p2p.laddr "0.0.0.0:46656" \
  --api.address tcp://localhost:1318

Run your full node with the following command:

rollkit start \
  --rollkit.da_address http://127.0.0.1:7980 \
  --p2p.seeds $P2P_ID@127.0.0.1:26656 \
  --minimum-gas-prices 0stake \
  --rpc.laddr tcp://127.0.0.1:46657 \
  --grpc.address 127.0.0.1:9390 \
  --p2p.laddr "0.0.0.0:46656" \
  --api.address tcp://localhost:1318 \
  --rollkit.sequencer_rollup_id gm

Key points about this command:

• rollkit.sequencer_rollup_id is generally the $CHAIN_ID, which is gm in this case.
• 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.

Conclusion

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