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Start Besu

Nodes can connect to Ethereum Mainnet, Linea, and their respective public testnets.

Use the besu command with the required command line options to start a node.

Prerequisites​

Besu installed

Local block data​

When connecting to a network other than the network previously connected to, you must either delete the local block data or use the --data-path option to specify a different data directory.

To delete the local block data, delete the database directory in the besu/build/distribution/besu-<version> directory.

Genesis configuration​

Besu specifies the genesis configuration, and sets the network ID and bootnodes when connecting to ETH testnets, and Mainnet.

The genesis files defining the genesis configurations are in the Besu source files.

To define a genesis configuration, create a genesis file (for example, genesis.json) and specify the file using the --genesis-file option.

Syncing and storage​

By default, Besu syncs to the current state of the blockchain using snap sync in:

  • Networks specified using --network.
  • Ethereum Mainnet.

We recommend using snap sync for a faster sync, by starting Besu with --sync-mode=SNAP.

By default, Besu stores data in the Bonsai Tries format.

Run a node on an Ethereum testnet​

To run a node on Hoodi specifying a data directory:

besu --network=hoodi --data-path=<path>/<hoodidata-path>

Where <path> and <hoodidata-path> are the path and directory to save the Hoodi chain data to.

See the guide on connecting to a testnet for more information.

Run a node on Ethereum Mainnet​

To run a node on the Ethereum Mainnet:

besu

To run a node on Mainnet with the HTTP JSON-RPC service enabled and available for localhost only:

besu --rpc-http-enabled

See the guide on connecting to Mainnet for more information.

Run a node for local development​

Besu doesn't provide a built-in development network. Use one of the following instead:

  • Ephemery is a public testnet that resets periodically. Start Besu with --network=ephemery and pair it with a consensus client, as described in Run Besu and Teku on a testnet.
  • Kurtosis runs a self-contained network of execution and consensus clients in Docker.

To run an isolated network that you control, define your own genesis file and start a private network. The Developer Quickstart generates one for you.

Confirm node is running​

If you started Besu with the --rpc-http-enabled option, use cURL to call JSON-RPC API methods to confirm the node is running.

  • eth_chainId returns the chain ID of the network.

    curl -X POST --data '{"jsonrpc":"2.0","method":"eth_chainId","params":[],"id":1}' localhost:8545/ -H "Content-Type: application/json"

  • eth_syncing returns the starting, current, and highest block.

    curl -X POST --data '{"jsonrpc":"2.0","method":"eth_syncing","params":[],"id":1}' localhost:8545/ -H "Content-Type: application/json"

    For example, after connecting to Mainnet, eth_syncing will return something similar to:

    {
      "jsonrpc": "2.0",
      "id": 1,
      "result": {
        "startingBlock": "0x0",
        "currentBlock": "0x2d0",
        "highestBlock": "0x66c0"
      }
    }