Verifying Optimism Challenger

Once you have installed and started the Optimism Challenger, it is crucial to verify that it is operating correctly and actively participating in the Fault Proof system.

Service Status

First, ensure the service is active and running:

sudo systemctl status op-challenger

You should see Active: active (running) in the output.

Log Verification

The most effective way to verify operation is by checking the logs.

sudo journalctl -fu op-challenger

Signs of a Healthy Challenger:

  1. Game Tracking: You should see logs indicating that the challenger is tracking “games”.

    INFO [01-01|12:00:00] Acted on game    game=0x... type=FaultDisputeGame status=InProgress

  2. No Errors: Ensure there are no repeated error messages regarding connection to the L1 node or the dispute game factory.

Monitoring

A Grafana dashboard “Op - Challenger” is available in the Ethereum on ARM monitoring stack (if installed). This dashboard provides visual insights into:

  • Game Status: The number of active games and their statuses.

  • Resolution Rate: How many games are being resolved over time.

  • Service Uptime: Historical uptime of the challenger service.

Troubleshooting

Issue: “Failed to connect to L1”

  • Check that your L1 Ethereum node (Geth/Nethermind) is fully synced.

  • Verify the RPC URL in /etc/ethereum/op-challenger.conf.

Issue: “Game factory not found”

  • Ensure you are using the correct network configuration (Mainnet vs. Sepolia).

  • Check if the --game-factory-address is correctly set for the network.