If any OpenContrail service fails, start with a basic troubleshooting as described below. If it does not help, proceed with troubleshooting a specific service as required.
To preform basic service troubleshooting:
Log in to any OpenContrail controller node.
Verify the status of the service in question using the service <service_name> status command.
Inspect the logs of the service in question in
/var/log/contrail/<service-name>.log.
Restart the service using the service <service_name> restart command.
Verify whether the service is not flapping. For example, see: Verify the OpenContrail svc-monitor.