Connect to a testnet

Run Besu as an execution client with any consensus client on the Goerli and Sepolia testnets.

If you’re using Teku as a consensus client, you can follow the Besu and Teku testnet tutorial.

Prerequisites

• Besu installed.
• A consensus client installed. For example, Teku.

Steps

1. Generate the shared secret

Run the following command:

openssl rand -hex 32 | tr -d "\n" > jwtsecret.hex

You will specify jwtsecret.hex when starting Besu and the consensus client. This is a shared JWT secret the clients use to authenticate each other when using the Engine API.

2. Start Besu

Run the following command or specify the options in a configuration file:

besu \
  --network=goerli            \
  --rpc-http-enabled=true     \
  --rpc-http-host=0.0.0.0     \
  --rpc-http-cors-origins="*" \
  --rpc-ws-enabled=true       \
  --rpc-ws-host=0.0.0.0       \
  --host-allowlist="*"        \
  --engine-host-allowlist="*" \
  --engine-rpc-enabled        \
  --engine-jwt-secret=<path to jwtsecret.hex>

besu \
  --network=sepolia           \
  --rpc-http-enabled=true     \
  --rpc-http-host=0.0.0.0     \
  --rpc-http-cors-origins="*" \
  --rpc-ws-enabled=true       \
  --rpc-ws-host=0.0.0.0       \
  --host-allowlist="*"        \
  --engine-host-allowlist="*" \
  --engine-rpc-enabled        \
  --engine-jwt-secret=<path to jwtsecret.hex>

Specify the path to the jwtsecret.hex file generated in step 1 using the --engine-jwt-secret option.

You can modify the option values and add other command line options as needed.

Ensure Besu is fully synced before submitting your staking deposit in the next step. This can take several days.

3. Generate validator keys and stake ETH

If you’re running a beacon node only, skip to the next step.

If you’re running a validator client, create a test Ethereum address (you can do this in MetaMask). Fund this address with testnet ETH (32 ETH and gas fees for each validator) using a faucet. See the list of Goerli faucets and Sepolia faucets.

Generate validator keys and stake your testnet ETH for one or more validators using the Goerli Staking Launchpad.

4. Start the consensus client

Refer to your consensus client documentation to configure and start the consensus client.

If you’re using Teku, follow the Besu and Teku testnet tutorial.

5. After starting the clients

After starting Besu and the consensus client, your node starts syncing and connecting to peers.

2022-03-21 20:42:09.295-07:00 | EthScheduler-Timer-0 | INFO  | FullSyncTargetManager | No sync target, waiting for peers. Current peers: 0
2022-03-21 20:42:14.298-07:00 | EthScheduler-Timer-0 | INFO  | FullSyncTargetManager | No sync target, waiting for peers. Current peers: 0
2022-03-21 20:42:14.848-07:00 | nioEventLoopGroup-3-8 | INFO  | FullSyncTargetManager | No sync target, waiting for peers. Current peers: 4
2022-03-21 20:42:18.452-07:00 | nioEventLoopGroup-3-8 | INFO  | SyncTargetManager | Found common ancestor with peer Peer 0xab3a286b181721c794... at block 55127
2022-03-21 20:42:18.454-07:00 | nioEventLoopGroup-3-8 | INFO  | PipelineChainDownloader | PipelineChain download complete

2022-03-21 20:43:24.355 INFO  - Syncing     *** Target slot: 76092, Head slot: 2680, Remaining slots: 73412, Connected peers: 8
2022-03-21 20:43:36.363 INFO  - Syncing     *** Target slot: 76093, Head slot: 2879, Remaining slots: 73214, Connected peers: 10
2022-03-21 20:43:48.327 INFO  - Syncing     *** Target slot: 76094, Head slot: 3080, Remaining slots: 73014, Connected peers: 8
2022-03-21 20:44:00.339 INFO  - Syncing     *** Target slot: 76095, Head slot: 3317, Remaining slots: 72778, Connected peers: 6
2022-03-21 20:44:12.353 INFO  - Syncing     *** Target slot: 76096, Head slot: 3519, Remaining slots: 72577, Connected peers: 9

You can check your validator status by searching your Ethereum address on the Goerli Beacon Chain explorer. It may take up to multiple days for your validator to be activated and start proposing blocks.