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Run a split validator node

Running split validators for Arbitrum chains​

Split validators separate the validation work to a stateless worker, which provides several key benefits:

  • Resource management: Easier to scale and manage compute resources independently
  • Fault isolation: Prevents database corruption if the validation worker crashes (e.g., due to OOM errors)
  • Flexibility: Allows running multiple validation workers for horizontal scalability

This guide explains how to set up a split validator configuration for Arbitrum chains by running a Nitro node (staker) and a validation node separately.

Before you read this doc, please ensure you have already walked through run a validator docs to understand the basics of a validator node.

Prerequisites​

  • Docker or Kubernetes with Helm installed
  • Staker private key
  • Chain information JSON for your Arbitrum chain

Docker deployment guide​

Step 1: Set up the validation node​

First, generate a JWT secret for secure communication:

xxd -l 32 -ps -c 40 /dev/urandom > /tmp/nitro-val.jwt

Start the validation node with the JWT secret:

docker run --rm -it \
  --entrypoint nitro-val \
  -p 0.0.0.0:5200:5200 \
  offchainlabs/nitro-node:v3.6.4-28199cd \
  --auth.addr 127.0.0.1 \
  --auth.origins 0.0.0.0 \
  --auth.jwtsecret /tmp/nitro-val.jwt \
  --auth.port 5200

The validation node will listen on port 5200.

Step 2: Set up the staker node​

Copy the JWT secret to your mount directory:

cp /tmp/nitro-val.jwt /some/local/dir/arbitrum

Start the staker node with the following command, connecting it to your validation node:

docker run --rm -it \
  -v /some/local/dir/arbitrum:/home/user/.arbitrum \
  offchainlabs/nitro-node:v3.6.4-28199cd \
  --parent-chain.connection.url=<parent-chain-endpoint> \
  --node.staker.enable=true \
  --node.staker.strategy=MakeNodes \
  --node.staker.parent-chain-wallet.private-key=<staker_private_key> \
  --chain.info-json=<Your_chain_info> \
  --execution.forwarding-target=<forwarding_target> \
  --node.block-validator.validation-server-configs-list="[{\"jwtsecret\":\"/home/user/.arbitrum/nitro-val.jwt\",\"url\":\"ws://Your_validation_address\"}]"

Replace the placeholders with your specific values:

  • <parent-chain-endpoint>: Your parent chain RPC endpoint
  • <staker_private_key>: Your staker's private key
  • <Your_chain_info>: Chain information JSON
  • <forwarding_target>: Your forwarding node URL (usually is the sequencer endpoint)
  • Your_validation_address: Address of your validation node (including port)

Kubernetes deployment with Helm​

Arbitrum provides a community Helm chart for Kubernetes deployment.

Step 1: Create validation node configuration​

Create a file named validation_values.yaml:

configmap:
  data:
    parent-chain:
      id: 1 # Use appropriate parent chain ID
      connection:
        url: 'https://your-parent-chain-rpc'
    execution:
      forwarding-target: 'https://your-forwarding-node'
    node:
      staker:
        enable: true
        strategy: 'MakeNodes'
        parent-chain-wallet:
          private-key: 'your-staker-private-key'
    chain:
      name: 'Your Chain Name'
      id: 42161 # Your chain ID
      info-json: '[Your chain info JSON]'

jwtSecret:
  enabled: true
  value: 'Your 32 bytes hex jwt'

validator:
  enabled: true
  splitvalidator:
    deployments:
      - name: 'current'

Step 2: Deploy the validation node​

helm install nitro-validator offchainlabs/nitro --values validation_values.yaml

Monitoring and maintenance​

  • Monitor your validator and staker logs regularly:

    # For Docker
    docker logs -f <container_id>

    # For Kubernetes
    kubectl logs -f <POD>

  • Check validator and staker status through the Arbitrum dashboard or API

Additional configurations for validation nodes​

To get a full list of parameters for the validation node, you can run the following command:

docker run --rm -it --entrypoint nitro-val  offchainlabs/nitro-node:v3.6.4-28199cd  --help

Additional configurations for helm charts​

For more advanced helm chart configurations, please refer to the Arbitrum community Helm Chart README