Running a Sequencer

Overview

This guide covers sequencer lifecycle management on the Aztec network: keystore configuration, node setup, registration, ongoing operations, and eventual exit.

Sequencer nodes are critical infrastructure responsible for ordering transactions and producing blocks. They perform three key actions:

1. Assemble unprocessed transactions and propose the next block
2. Attest to correct execution of transactions in proposed blocks (when part of the sequencer committee)
3. Submit successfully attested blocks to L1

Before publication, blocks must be validated by a committee of sequencer nodes who re-execute public transactions and verify private function proofs. Committee members attest to validity by signing the block header.

Once sufficient attestations are collected (two-thirds of the committee plus one), the block can be submitted to L1.

Minimum Hardware Requirements

• 2 core / 4 vCPU (released in 2015 or later)
• 16 GB RAM
• 1 TB NVMe SSD
• 25 Mbps network connection

These requirements are subject to change as the network throughput increases.

Before proceeding: Ensure you've reviewed and completed the prerequisites for the Docker Compose method. This guide uses Docker Compose, which is the recommended approach for sequencer nodes.

Keystore Explanation

Sequencers require private keys to identify themselves as valid proposers and attesters. These keys are configured through a keystore file.

Keystore Structure

The keystore file (keystore.json) uses the following structure:

{
  "schemaVersion": 1,
  "validators": [
    {
      "attester": ["ETH_PRIVATE_KEY_0"],
      "publisher": ["ETH_PRIVATE_KEY_1"],
      "coinbase": "ETH_ADDRESS_2"
    }
  ]
}

Field Descriptions

attester (required)

Your sequencer's identity. The Ethereum address derived from this private key uniquely identifies your sequencer in the network. This key is used to sign block proposals and attestations.

• Format: Array of Ethereum private keys
• Purpose: Signs attestations and proposals
• Identity: The corresponding Ethereum address is your sequencer's unique identifier

publisher (optional)

Private key for sending block proposals to L1. This account needs ETH funding to pay for L1 gas.

• Format: Array of Ethereum private keys
• Default: Uses attester key if not specified Rule of thumb: Ensure every publisher account maintains at least 0.1 ETH per attester account it serves. This balance allows the selected publisher to successfully post transactions when chosen.

tip

If you're using the same key for both attester and publisher, you can omit the publisher field entirely from your keystore.

coinbase (optional)

Ethereum address that receives all L1 block rewards and tx fees.

• Format: Ethereum address
• Default: Uses attester address if not specified

Generating Keys

Before creating your keystore file, you'll need to generate the required keys.

Ethereum Private Keys

Generate Ethereum private keys using Foundry's cast tool:

# Generate a new wallet with a 24-word mnemonic
cast wallet new-mnemonic --words 24

# This outputs a mnemonic phrase, a derived address, and private key
# Save these securely - you'll need the private key for the keystore

At a minimum, you need one Ethereum private key for the attester field. Optionally, you can generate a separate key for the publisher field and a separate address for the coinbase field.

Setup with Docker Compose

Step 1: Set Up Directory Structure

Create the directory structure for sequencer data storage:

mkdir -p aztec-sequencer/keys aztec-sequencer/data
cd aztec-sequencer
touch .env

Step 2: Create Keystore File

Create a keystore.json file in your aztec-sequencer/keys folder with your generated keys:

{
  "schemaVersion": 1,
  "validators": [
    {
      "attester": ["ETH_PRIVATE_KEY_0"],
      "publisher": ["ETH_PRIVATE_KEY_1"],
      "coinbase": "ETH_ADDRESS_2"
    }
  ]
}

Replace the placeholder values with your actual keys and addresses generated in the previous section.

warning

Publisher accounts submit block proposals to L1. Each publisher operates independently, and the system does not retry with another publisher if a transaction fails due to insufficient funds.

Examples:

• 3 attesters with 1 publisher → Maintain ≥ 0.3 ETH in that publisher account
• 3 attesters with 2 publishers → Maintain ≥ 0.15 ETH in each publisher account (0.3 ETH total)

Maintaining these minimum balances prevents failed block publications caused by low gas funds.

Step 3: Configure Environment Variables

Add the following to your .env file:

DATA_DIRECTORY=./data
KEY_STORE_DIRECTORY=./keys
LOG_LEVEL=info
ETHEREUM_HOSTS=[your L1 execution endpoint, or a comma separated list if you have multiple]
L1_CONSENSUS_HOST_URLS=[your L1 consensus endpoint, or a comma separated list if you have multiple]
P2P_IP=[your external IP address]
P2P_PORT=40400
AZTEC_PORT=8080
AZTEC_ADMIN_PORT=8880

tip

Find your public IP address with: curl ipv4.icanhazip.com

Step 4: Create Docker Compose File

Create a docker-compose.yml file in your aztec-sequencer directory:

services:
  aztec-sequencer:
    image: "aztecprotocol/aztec:2.0.2"
    container_name: "aztec-sequencer"
    ports:
      - ${AZTEC_PORT}:${AZTEC_PORT}
      - ${AZTEC_ADMIN_PORT}:${AZTEC_ADMIN_PORT}
      - ${P2P_PORT}:${P2P_PORT}
      - ${P2P_PORT}:${P2P_PORT}/udp
    volumes:
      - ${DATA_DIRECTORY}:/var/lib/data
      - ${KEY_STORE_DIRECTORY}:/var/lib/keystore
    environment:
      KEY_STORE_DIRECTORY: /var/lib/keystore
      DATA_DIRECTORY: /var/lib/data
      LOG_LEVEL: ${LOG_LEVEL}
      ETHEREUM_HOSTS: ${ETHEREUM_HOSTS}
      L1_CONSENSUS_HOST_URLS: ${L1_CONSENSUS_HOST_URLS}
      P2P_IP: ${P2P_IP}
      P2P_PORT: ${P2P_PORT}
      AZTEC_PORT: ${AZTEC_PORT}
      AZTEC_ADMIN_PORT: ${AZTEC_ADMIN_PORT}
    entrypoint: >-
      node
      --no-warnings
      /usr/src/yarn-project/aztec/dest/bin/index.js
      start
      --node
      --archiver
      --sequencer
      --network testnet
    networks:
      - aztec
    restart: always

networks:
  aztec:
    name: aztec

This configuration includes only essential settings. The --network testnet flag applies network-specific defaults—see the CLI reference for all available configuration options.

Step 5: Start the Sequencer

Start the sequencer:

docker compose up -d

Verification

Once your sequencer is running, verify it's working correctly:

Check Sync Status

Check the current sync status (this may take a few minutes):

curl -s -X POST -H 'Content-Type: application/json' \
-d '{"jsonrpc":"2.0","method":"node_getL2Tips","params":[],"id":67}' \
http://localhost:8080 | jq -r ".result.proven.number"

Compare the output with block explorers like Aztec Scan or Aztec Explorer.

Check Node Status

curl http://localhost:8080/status

View Logs

docker compose logs -f aztec-sequencer

Registering a Sequencer

After your sequencer node is set up and running, you must register it with the network to join the sequencer set.

Registration Process

Complete the onboarding process at testnet.aztec.network using zkPassport.

This process will:

1. Verify your identity using zkPassport
2. Register your sequencer's attester address with the network
3. Add you to the sequencer set once approved

Your sequencer's identity is determined by the attester address derived from the private key in your keystore file.

Monitoring Sequencer Status

You can query the status of any sequencer (attester) using the Rollup and GSE (Governance Staking Escrow) contracts on L1.

Prerequisites

• Foundry installed (cast command)
• Ethereum RPC endpoint
• Registry contract address for your network

Get Contract Addresses

First, get the canonical Rollup contract address from the Registry:

# Get the canonical rollup address
cast call [REGISTRY_CONTRACT_ADDRESS] "getCanonicalRollup()" --rpc-url [YOUR_RPC_URL]

Then get the GSE contract address from the Rollup:

# Get the GSE contract address
cast call [ROLLUP_ADDRESS] "getGSE()" --rpc-url [YOUR_RPC_URL]

Query Sequencer Status

Check the complete status and information for a specific sequencer:

# Get full attester view (status, balance, exit info, config)
cast call [ROLLUP_ADDRESS] "getAttesterView(address)" [ATTESTER_ADDRESS] --rpc-url [YOUR_RPC_URL]

This returns an AttesterView struct containing:

1. status - The sequencer's current status (see Status Codes below)
2. effectiveBalance - The sequencer's effective stake balance
3. exit - Exit information (if the sequencer is exiting)
4. config - Attester configuration (withdrawer address and public key)

Status Codes

Status	Name	Meaning
0	NONE	The sequencer does not exist in the sequencer set
1	VALIDATING	The sequencer is currently active and participating in consensus
2	ZOMBIE	The sequencer is not active (balance fell below ejection threshold, possibly due to slashing) but still has funds in the system
3	EXITING	The sequencer has initiated withdrawal and is in the exit delay period

Performance Monitoring

Track your sequencer's performance by monitoring:

• Effective balance - Should remain above the ejection threshold
• Status - Should be VALIDATING for active participation
• Attestation rate - How many attestations you've successfully submitted
• Proposal success rate - How many of your proposed blocks were accepted
• Network participation metrics - Overall participation in network consensus

Exiting a Sequencer

warning

Information about the exit process will be added when the mechanism is finalized. Check the Aztec Discord for the latest information on exiting the sequencer set.

Troubleshooting

Port forwarding not working

Issue: Your node cannot connect to peers.

Solutions:

• Verify your external IP address matches the P2P_IP setting
• Check firewall rules on your router and local machine
• Test connectivity using: nc -zv [your-ip] 40400

Sequencer not syncing

Issue: Your node is not synchronizing with the network.

Solutions:

• Check L1 endpoint connectivity
• Verify both execution and consensus clients are fully synced
• Review logs for specific error messages
• Ensure L1 endpoints support high throughput

Keystore issues

Issue: Keystore not loading or errors about invalid keys.

Solutions:

• Ensure keystore.json is properly formatted
• Verify private keys are valid Ethereum private keys
• Check file permissions on the keys directory

Docker issues

Issue: Container won't start or crashes.

Solutions:

• Ensure Docker and Docker Compose are up to date
• Check disk space availability
• Verify the .env file is properly formatted
• Review container logs: docker compose logs aztec-sequencer

Common Issues

See the Operator FAQ for additional common issues and resolutions.

Next Steps

• Monitor your sequencer's performance and attestation rate
• Join the Aztec Discord for operator support
• Review creating and voting on proposals for participating in governance
• Set up high availability to run your sequencer across multiple nodes for redundancy
• Learn about advanced keystore patterns for running multiple sequencer identities or complex configurations