Run Besu and Teku on a testnet

Run Besu as an execution client and Teku as a consensus client on the Goerli and Sepolia Ethereum testnets.

1. Install Besu and Teku

Install Besu and Teku.

Ensure you meet the prerequisites for the installation option you use. For example, you must have Java 11+ if using the Besu and Teku binary distributions.

Ensure you meet the system requirements for Besu on public networks.

2. 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 Teku. This is a shared JWT secret the clients use to authenticate each other when using the Engine API.

3. 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="*" \
  --Xmerge-support=true       \
  --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="*" \
  --Xmerge-support=true       \
  --engine-jwt-secret=<path to jwtsecret.hex>

Specify the path to the jwtsecret.hex file generated in step 2 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.

4. Generate validator keys and stake ETH

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

If you’re also 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.

5. Start Teku

Open a new terminal window.

Beacon node only

To run Teku as a beacon node only (without validator duties), run the following command or specify the options in the Teku configuration file:

teku \
  --network=goerli                             \
  --ee-endpoint=http://localhost:8551          \
  --ee-jwt-secret-file=<path to jwtsecret.hex> \
  --metrics-enabled=true                       \
  --rest-api-enabled=true

teku \
  --network=sepolia                            \
  --ee-endpoint=http://localhost:8551          \
  --ee-jwt-secret-file=<path to jwtsecret.hex> \
  --metrics-enabled=true                       \
  --rest-api-enabled=true

Specify the path to the jwtsecret.hex file generated in step 2 using the --ee-jwt-secret-file option.

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

Beacon node and validator client

To run Teku as a beacon node and validator in a single process, run the following command or specify the options in the Teku configuration file:

teku \
  --network=goerli                                          \
  --ee-endpoint=http://localhost:8551                       \
  --ee-jwt-secret-file=<path to jwtsecret.hex>              \
  --metrics-enabled=true                                    \
  --rest-api-enabled=true                                   \
  --validators-proposer-default-fee-recipient=<ETH address> \
  --validator-keys=<path to key file>:<path to password file>[,<path to key file>:<path to password file>,...]

Specify:

• The path to the jwtsecret.hex file generated in step 2 using the --ee-jwt-secret-file option.
• The test Ethereum address created in step 4 as the default fee recipient using the --validators-proposer-default-fee-recipient option.
• The paths to the keystore .json file and password .txt file created in step 4 for each validator using the --validator-keys option. Separate the .json and .txt files with a colon, and separate entries for multiple validators with commas.

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

After starting Besu and Teku

After starting Besu and Teku, 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.