Nimbus

Select a configuration for Nimbus. Running a standalone validator configuration is recommended for best modularity and redundancy.

Standalone Validator (Recommended)

Create a service user for the validator service, as this improves security, then create data directories.

sudo adduser --system --no-create-home --group validator
sudo mkdir -p /var/lib/nimbus_validator

The following command will import your validator keys.

Enter your keystore password to import accounts.

sudo /usr/local/bin/nimbus_beacon_node deposits import \
  --data-dir=/var/lib/nimbus_validator $HOME/staking-deposit-cli/validator_keys

WARNING: Do not import your validator keys into multiple validator clients and run them at the same time, or you might get slashed. If moving validators to a new setup or different validator client, ensure deletion of the previous validator keys before continuing.

Now you can verify the accounts were imported successfully by doing a directory listing.

sudo ls -l /var/lib/nimbus_validator/validators

You should see a folder named for each of your validator's pubkey.

Create a systemd unit file to define your validator.service configuration.

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

Paste the following configuration into the file.

[Unit]
Description=Nimbus Validator Client service for Mainnet
Wants=network-online.target
After=network-online.target
Documentation=https://www.nodebridgeafrica.com

[Service]
Type=simple
User=validator
Group=validator
Restart=on-failure
RestartSec=3
KillSignal=SIGINT
TimeoutStopSec=900
ExecStart=/usr/local/bin/nimbus_validator_client \
  --data-dir=/var/lib/nimbus_validator \
  --metrics \
  --metrics-port=8009 \
  --beacon-node=http://127.0.0.1:5052 \
  --non-interactive \
  --graffiti="🏠🥩🪙🛡️" \
  --suggested-fee-recipient=<0x_CHANGE_THIS_TO_MY_ETH_FEE_RECIPIENT_ADDRESS>
  
[Install]
WantedBy=multi-user.target

• Replace<0x_CHANGE_THIS_TO_MY_ETH_FEE_RECIPIENT_ADDRESS> with your own Ethereum address that you control. Tips are sent to this address and are immediately spendable.

• If you wish to customize a short message that is included when you produce a block, add your message to the --graffiti. Maximum length is 16 characters.

To exit and save, press Ctrl + X, then Y, then Enter.

Setup ownership permissions, including hardening the access to this directory.

sudo chown -R validator:validator /var/lib/nimbus_validator
sudo chmod -R 700 /var/lib/nimbus_validator

Run the following to enable auto-start at boot time.

sudo systemctl daemon-reload
sudo systemctl enable validator

Finally, start your validator client and check it's status.

sudo systemctl start validator
sudo systemctl status validator

Check your logs to confirm that the validator clients are up and functioning.

sudo journalctl -fu validator | ccze

Combined (BN+VC)

Note: In the combined configuration, Nimbus runs both validator client and beacon chain client in one systemd service process.

Setup ownership permissions, including hardening the access to this directory.

sudo chown -R consensus:consensus /var/lib/nimbus
sudo chmod -R 700 /var/lib/nimbus

Finally, restart Nimbus to use the new validators.

sudo systemctl restart consensus

Check your logs to confirm that the validators are up and functioning.

sudo journalctl -fu consensus | ccze

For example when using 2 validators, logs will show the following:

Loading validators             topics="beacval" validatorsDir=/var/lib/nimbus/validators keystore_cache_available=true
Local validator attached       topics="val_pool" pubkey=95d39860a0d6ea3b92cba78069d21f3a validator=95d39860 initial_fee_recipient=81ba8d5c4ae850
Local validator attached       topics="val_pool" pubkey=82b225f66476962b161ed015786df00f validator=82b225f6 initial_fee_recipient=81ba8d5c4ae850

Press Ctrl + C to exit the logs.

Example of Synced Nimbus Validator Client Logs

• Once the validator is active and proceeded through the validator activation queue, attestation messages will appear indicating successful attestations.

• Notice the key words "Attestation sent".

nimbus_beacon_node[292966]: INF 2023-02-05 01:25:26.263+00:00 Attestation sent      attestation="(aggregation_bits: 0b00000000000000000000000000000000000000000000000000000000, data: (slot: 31235, index: 3, beacon_block_root: \"ca3213f1\", source: \"1901:9deza1289\", target: \"1901:6ab1fafff\"), signature: \"32173064\")" delay=46ms543us294ns subnet_id=20

Cleanup leftover validator_keys

Verify that you have backups of validator_keys directory. The contents are the keystore files.

Having backup copies of your validator_keys directory on USB media can make recovery from node problems quicker. Validator keys can always be regenerated from secret recovery mnemonic phrase.

You may safely delete the directory.

# Remove default validator_key directory
sudo rm -r $HOME/staking-deposit-cli/validator_keys