Simulation troubleshooting

Check if port 5001 is already in use:

lsof -i :5001
# Kill the process if needed
kill -9 <PID>

Ensure Python dependencies are installed:

cd services/simulation
pip install flask flask-cors boto3 requests

Make the management script executable:

chmod +x manage_simulation.sh

Start the service and check logs:

./manage_simulation.sh start
./manage_simulation.sh logs

Vehicles must have IoT certificates to be used in simulations. Create vehicles in the Fleet Manager UI with "Create IoT Core certificate" enabled.

Verify vehicles have certificates in DynamoDB:

aws dynamodb scan --table-name cms-dev-storage-vehicles \
  --filter-expression "has_certificate = :t" \
  --expression-attribute-values '{":t": {"BOOL": true}}' \
  --select COUNT

If using FleetWise Edge mode, verify the vehicle VIN exists in the vehicles table and has a valid IoT thing registered.

Verify Docker is running:

docker info

Check if the FWE Docker image is built:

docker images | grep fwe

If the image is missing, build it:

cd services/simulation
./build_sim_image.sh

Check the FWE container logs for startup errors:

docker logs fwe-YOUR_VIN --tail 50

Verify the FWE persistency files are generated correctly:

ls -la services/simulation/fwe_config/persistency/

Check the simulation logs for MQTT publish errors:

tail -f services/simulation/simulation_service.log

Verify the IoT endpoint is reachable:

aws iot describe-endpoint --endpoint-type iot:Data-ATS

Verify the vehicle’s IoT certificate is activated:

# Get certificate ARN from DynamoDB, then check status
aws iot describe-certificate --certificate-id YOUR_CERT_ID \
  --query "certificateDescription.status"

Check the full pipeline: IoT Core → MSK → SimulatorPreprocessor → EventDrivenTelemetryProcessor → DynamoDB/Redis. Any stopped Flink processor in this chain will break the pipeline (see Problem: Telemetry reaching MSK but not appearing in DynamoDB).