7.1 Slasher Configuration

Running a slasher service helps monitor and report malicious validator behavior, contributing to the overall health and security of the network. This guide explains how to enable or disable the slasher for regular nodes and validators.

tip

Further details can be found on the Slashing and Panelties and Slasher Service pages in the 🧠 Theory section.

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The following steps are performed on your 📟 node server.

1. Stop Node Operation

Depending on your setup method, there are different ways to stop your node before applying updates.

LUKSO CLI

cd <lukso-working-directory>
lukso stop

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Exchange <lukso-working-directory> with the path of the node folder.

Service Automation

sudo systemctl stop lukso-validator

Force Client Shutdown

Geth

sudo pkill geth

Erigon

sudo pkill erigon

Nethermind

sudo pkill nethermind

Besu

sudo pkill besu

Teku

sudo pkill teku

Nimbus-Eth2

sudo pkill nimbus_beacon_node
sudo pkill nimbus_validator_client

Lighthouse

sudo pkill lighthouse

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The Lighthouse client uses a single binary for both the consensus and validator processes.

Prysm

sudo pkill prysm
sudo pkill validator

2. Configure Slasher Service

If you are running a validator node using the LUKSO CLI setup, the slasher is activated by default to increase watchers for malicious events during network downtimes of bigger services. For regular nodes or custom setups, the slasher service is disabled.

If you are runnning on lower end hardware or prefer to safe disk space, you can disable it. Regular nodes can use the similar process to activate the additional service without participating in the consensus.

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The Teku and Nimbus-Eth2 clients do not have separate slasher services that create a database and keep track of the historical misbehaviours. Instead, they only come with validator precautions such as slashing-protection or doppelganger-detection that check against their own keys before committing validator duties.

Disable Slasher for Validator Node

Depending on your setup method, there are different ways to start your staking node without the slasher service.

LUKSO CLI

cd <lukso-working-directory>

# Start Mainnet Validator without Slasher
lukso start --validator --transaction-fee-recipient "<your-fee-recipient-address>" --checkpoint-sync -no-slasher

# Start Testnet Validator without Slasher
lukso start --testnet --validator --transaction-fee-recipient "<your-fee-recipient-address>" --checkpoint-sync -no-slasher

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The following properties need to be exchanged:

• <lukso-working-directory> with the path of the node folder
• <your-fee-recipient-address> with the wallet address receiving staking profits

Service Automation

Open the startup script within your node directory with your preferred text editor.

Vim

sudo vim <lukso-working-directory>/static/lukso_startup.sh

Nano

sudo nano <lukso-working-directory>/static/lukso_startup.sh

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Exchange <lukso-working-directory> with the path to the node folder.

Add the flag to disable the slasher service as a new line to the start command, then save and exit the file.

exec /usr/local/bin/lukso start \
        --validator \
        --validator-wallet-password ./static/<your-generic-password-file> \
        --transaction-fee-recipient "<your-fee-recipient-address>" \
        --checkpoint-sync \
        --no-slasher

After the startup script was updated, you can restart the node by executing the related service.

sudo systemctl start lukso-validator

Activate Slasher for Regular Node

Depending on your setup method, there are different ways to start your regular node with the slasher service flags. The custom flags provided during startup will be passed down from the LUKSO CLI to the consensus clients.

LUKSO CLI

cd <lukso-working-directory>

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Exchange <lukso-working-directory> with the path to the node folder.

Lighthouse

# Start Mainnet Slasher Node
lukso start --checkpoint-sync --lighthouse-slasher

# Start Testnet Slasher Node
lukso start --testnet --checkpoint-sync --lighthouse-slasher

Prysm

# Start Mainnet Slasher Node
lukso start --checkpoint-sync --prysm-slasher

# Start Testnet Slasher Node
lukso start --testnet --checkpoint-sync --prysm-slasher

Service Automation

Open the startup script within your node directory with your preferred text editor.

Vim

cd <lukso-working-directory>/static
vim lukso_startup.sh

Nano

cd <lukso-working-directory>/static
nano lukso_startup.sh

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Exchange <lukso-working-directory> with the path to the node folder.

Add the flag to activate the slasher service as a new line to the start command, then save and exit the file.

Lighthouse

exec /usr/local/bin/lukso start \
        --validator \
        --validator-wallet-password ./static/<your-generic-password-file> \
        --transaction-fee-recipient "<your-fee-recipient-address>" \
        --checkpoint-sync \
        --lighthouse-slasher

Prysm

exec /usr/local/bin/lukso start \
        --validator \
        --validator-wallet-password ./static/<your-generic-password-file> \
        --transaction-fee-recipient "<your-fee-recipient-address>" \
        --checkpoint-sync \
        --prysm-slasher

After the startup script was updated, you can restart the node by executing the related service.

sudo systemctl start lukso-validator

After the clients were started, verify that their services are still up.

sudo lukso status

4. Remove Slasher Data

If you previously ran a slasher service, you can delete the unused database from your node directory and free storage space.

cd <lukso-working-directory>

# Remove Slasher Database for Mainnet Node
rm -rf /mainnet-data/consensus/beaconchaindata/slasher.db

# Remove Slasher Database for Testnet Node
rm -rf /testnet-data/consensus/beaconchaindata/slasher.db

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Exchange <lukso-working-directory> with the path to the node folder.

🎨 DAppNode

On a DAppNode setup, the Prysm client can be adjusted from the user interface.

1. Stop Node Operation: Stop the execution and consensus client within the Node Operation View.

2. Navigate to Staker Menu: Open the LUKSO Stakers menu and move into the Lukso Prysm Package.

3. Adjust Slasher Value: Navigate to the Configs window and add the slasher flag in the EXTRA_OPTS field.

Disable Slasher for Validator Node

--no-slasher

Activate Slasher for Regular Node

--slasher

4. Restart the Node: Restart the execution and consensus client within the Node Operation View.