Observed communication drop in fabric with EVPN setup post contrail version upgrade , multiple configurations were pushed to leaf device caused flow disruption.

During contrail upgrade, service running in the controller will be restarted. Config-device-manager service when restarted will resync the configuration with managed devices

Follow the below steps to review and identify the trigger for configuration push to devices from Contrail

1. In contrail command, Navigate to Monitor --> Operations --> Jobs
2. Review each jobs and expand the job details and review the configuration push to devices.
3. Login to the QFX devices and run the command show system command. Co-relate the configuration push from contrail with the Job ID.