Teku VC

Download Teku

Follow the steps in this previous section to download Teku if you have not done so.

Teku BN

Create a new user account

sudo useradd --no-create-home --shell /bin/false teku_validator

Prepare the validator keystores

1) Create 3 new folders to store the validator client data, validator keystore, and the validator keystore password

2) Copy the validator keystores and it's password file into their respective folders

3) Change the owner of this folder to the teku user

4) Restrict permissions on this new folder such that only the owner is able to read, write, and execute files in this folder

sudo mkdir -p /var/lib/teku_validator/validator_keystores /var/lib/teku_validator/keystore_password
sudo cp ~/validator_keys/<validator_keystore.json> /var/lib/teku_validator/validator_keystores
sudo cp ~/validator_keys/<validator_keystore_password.txt> /var/lib/teku_validator/keystore_password
sudo chown -R teku_validator:teku_validator /var/lib/teku_validator
sudo chmod 700 /var/lib/teku_validator

Aside from the file extension, the validator_keystore_password file will need to be named identically as the validator signing keystore file (e.g. keystore-m-123.json, keystore-m-123.txt)

Configure the validator client service

Create a systemd configuration file for the Teku Validator Client service to run in the background.

sudo nano /etc/systemd/system/tekuvalidator.service

Paste the configuration parameters below into the file:

[Unit]
Description=Teku Validator Client (Holesky)
Wants=network-online.target
After=network-online.target
[Service]
User=teku_validator
Group=teku_validator
Type=simple
Restart=always
RestartSec=5
Environment="JAVA_OPTS=-Xmx6g"
Environment="TEKU_OPTS=-XX:-HeapDumpOnOutOfMemoryError"
ExecStart=/usr/local/bin/teku/bin/teku vc \
  --network=holesky \
  --data-path=/var/lib/teku_validator \
  --validator-keys=/var/lib/teku_validator/validator_keystores:/var/lib/teku_validator/keystore_password \
  --beacon-node-api-endpoint=http://<Internal_IP_address>:5052 \
  --validators-proposer-default-fee-recipient=<your_designated_ETH_wallet address> \
  --validators-proposer-blinded-blocks-enabled=true \
  --validators-graffiti="<your_graffiti_of_choice>" \
  --metrics-enabled=true \
  --metrics-port=8108 \
  --doppelganger-detection-enabled=true 

[Install]
WantedBy=multi-user.target

Once you're done, save with Ctrl+O and Enter, then exit with Ctrl+X. Understand and review your configuration summary below, and amend if needed.

Teku Validator Client configuration summary:

1. --network: Run the validator client service on the ETH Holesky testnet

2. --data-path: Specify the directory for Teku to store the validator info

3. --validator-keys: File path to the directory where your validator signing keystore and corresponding plain text password file are stored. Aside from the file extension (e.g. .json vs .txt), the password file will need to be named identically as the validator signing keystore file. For example:

   
4. --beacon-node-api-endpoint: URLs to connect to the main and backup consensus clients if any. This needs to be the same IP address set in your consensus client. Refer back here if you don't remember it.

5. --validators-proposer-default-fee-recipient: ETH wallet address to receive rewards from block proposals and MEV bribes

6. --validators-proposer-blinded-blocks-enabled: Required when using external builders to build blocks (e.g. MEV relays)

7. --validators-graffiti: Optional text to display on-chain when your validator proposes a block

8. --metrics-enabled: Enable metrics for monitoring

9. --metrics-port: Port to retrieve metrics for monitoring

10. --doppelganger-detection-enabled: Helps prevents slashing due to double signing by checking if your validator keys are already active on the network. Not a fool-proof solution.

Start the Teku Validator Client service

Reload the systemd daemon to register the changes made, start the Teku Validator Client, and check its status to make sure its running.

sudo systemctl daemon-reload
sudo systemctl start tekuvalidator.service
sudo systemctl status tekuvalidator.service

The output should say the Teku Validator Client is “active (running)”. Press CTRL-C to exit and the Teku Validator Client will continue to run.

Use the following command to check the logs for any warnings or errors:

sudo journalctl -fu tekuvalidator -o cat | ccze -A

Expected output:

Example output of the Teku VC running on the Goerli testnet. Look out for Holesky in your output.

Press CTRL-C to exit.

If the Teku Validator Client service is running smoothly, we can now enable it to fire up automatically when rebooting the system.

sudo systemctl enable tekuvalidator

Expected output:

Created symlink /etc/systemd/system/multi-user.target.wants/tekuvalidator.service → /etc/s

Remove duplicates of validator keystores

To prevent configuration mistakes leading to double signing in the future, remove duplicate copies of the validator signing keystores once everything is running smoothly.

sudo rm -r ~/validator_keys

Resources

• Releases: https://github.com/Consensys/teku/releases

• Documentation: https://docs.teku.consensys.io/introduction

• Discord: https://discord.gg/consensys (Select the Teku channel)