Run a Sequencer Node

Run kona-node in sequencer mode from the command line, including required arguments, sequencer-specific flags, and example configurations.

This guide shows how to run kona-node in sequencer mode from the command line. For how sequencer mode works internally and how to configure it programmatically through the Node SDK, see the sequencer mode design page.

Sequencer mode is an advanced configuration primarily used by rollup operators. Most users will run nodes in the default validator mode.

Basic Sequencer Setup

To run a Kona node in sequencer mode:

kona-node node \
  --mode=Sequencer \
  --l1-eth-rpc=http://l1-node:8545 \
  --l1-beacon=http://l1-beacon:5052 \
  --l2-engine-rpc=http://l2-execution:8551 \
  --l2.jwt-secret=./jwt.hex \
  --p2p.sequencer.key.path=./p2p-sequencer.key \
  --chain=123456

Required Arguments

Required Configuration

Sequencer mode requires all standard node arguments plus the --mode=Sequencer flag and a block signer. Missing any required argument will prevent the node from starting.

Argument	Flag	Environment Variable	Description
Mode	--mode	KONA_NODE_MODE	Must be set to Sequencer
L1 RPC	--l1-eth-rpc	KONA_NODE_L1_ETH_RPC	L1 execution client RPC URL
L1 Beacon	--l1-beacon	KONA_NODE_L1_BEACON	L1 beacon API URL
L2 Engine	--l2-engine-rpc	KONA_NODE_L2_ENGINE_RPC	L2 engine API endpoint
JWT Secret	--l2.jwt-secret	KONA_NODE_L2_ENGINE_AUTH	Path to JWT secret file
Chain ID	--chain	KONA_NODE_L2_CHAIN_ID	L2 chain identifier
Block Signer	--p2p.sequencer.key.path, --p2p.sequencer.key, or --p2p.signer.endpoint with --p2p.signer.address	KONA_NODE_P2P_SEQUENCER_KEY_PATH, KONA_NODE_P2P_SEQUENCER_KEY, KONA_NODE_P2P_SIGNER_ENDPOINT, KONA_NODE_P2P_SIGNER_ADDRESS	Signs the blocks the sequencer gossips: a local key, or a remote op-signer

Sequencer-Specific Flags

Flag	Environment Variable	Default	Description
--sequencer.stopped	KONA_NODE_SEQUENCER_STOPPED	false	Start sequencer in stopped state
--sequencer.max-safe-lag	KONA_NODE_SEQUENCER_MAX_SAFE_LAG	0	Max L2 blocks between safe and unsafe heads
--sequencer.l1-confs	KONA_NODE_SEQUENCER_L1_CONFS	4	L1 confirmations for origin selection
--sequencer.recover	KONA_NODE_SEQUENCER_RECOVER	false	Force recovery mode operation
--conductor.rpc	KONA_NODE_CONDUCTOR_RPC	-	Conductor service RPC endpoint
--conductor.rpc.timeout	KONA_NODE_CONDUCTOR_RPC_TIMEOUT	1	Conductor RPC timeout (seconds)

The full flag catalogue, including the standard node arguments shared with validator mode, lives in the Kona node CLI reference.

Example Configurations

Basic Sequencer

kona-node node \
  --mode=Sequencer \
  --l1-eth-rpc=http://localhost:8545 \
  --l1-beacon=http://localhost:5052 \
  --l2-engine-rpc=http://localhost:8551 \
  --p2p.sequencer.key.path=./p2p-sequencer.key \
  --chain=42161

Sequencer with Conductor

kona-node node \
  --mode=Sequencer \
  --conductor.rpc=http://conductor:8080 \
  --conductor.rpc.timeout=5 \
  --sequencer.l1-confs=6 \
  --l1-eth-rpc=http://l1-node:8545 \
  --l1-beacon=http://l1-beacon:5052 \
  --l2-engine-rpc=http://l2-execution:8551 \
  --p2p.sequencer.key.path=./p2p-sequencer.key \
  --chain=123456

Recovery Mode Sequencer

kona-node node \
  --mode=Sequencer \
  --sequencer.recover=true \
  --sequencer.max-safe-lag=100 \
  --l1-eth-rpc=http://localhost:8545 \
  --l1-beacon=http://localhost:5052 \
  --l2-engine-rpc=http://localhost:8551 \
  --p2p.sequencer.key.path=./p2p-sequencer.key \
  --chain=42161

Key Considerations

Sequencer Operation

• L1 Confirmations: The --sequencer.l1-confs setting determines how many L1 blocks the sequencer waits before using an L1 block as an origin. Higher values provide more safety but increase latency.
• Recovery Mode: Use --sequencer.recover=true when the sequencer needs to catch up after being offline.
• Conductor Integration: For multi-sequencer deployments, configure the conductor service for proper leader election.

Running a sequencer in production requires careful consideration of infrastructure, monitoring, and failover procedures. Ensure proper JWT secret management and secure network configuration.