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Date of last update: November 1, 2022

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.

Note

Sepolia is a permissioned network and you can’t run a validator client on it without requesting to become a validator first. You can connect your consensus client using the beacon node only, without any validator duties.

Prerequisites

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.

Note

If you’re unable to get ETH using the faucet, you can ask for help on the EthStaker Discord.

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

Important

Save the password you use to generate each key pair in a .txt file. You should also have a .json file for each validator key pair.

Ensure your Besu node is fully synced before submitting your staking deposit. This can take several days.

4. Start the consensus client

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

Important

If you’re running a validator client, make sure you set a fee recipient address.

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.

Example

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

Caution

If you restart your node before snap or checkpoint sync completes, syncing restarts from scratch.

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.