Help us improve your experience.

Let us know what you think.

Do you have time for a two-minute survey?


Bidirectional Forwarding and Detection Health Check over Virtual Machine Interfaces


Contrail Networking supports BFD-based health checks for VMIs.

Health check for VMIs is already supported as poll-based checks with ping and curl commands. When enabled, these health checks run periodically, once every few seconds. Consequently, failure detection times can be quite large, always in seconds.

Health checks based on the BFD protocol provide failure detection and recovery in sub-second intervals, because applications are notified immediately upon BFD session state changes.

If BFD-based health check is configured, whenever a BFD session status is detected as Up or Down by the health-checker, corresponding logs are generated.

Logging is enabled in the contrail-vrouter-agent.conf file with the log severity level SYS_NOTICE.

You can view the log file in the location /var/log/contrail/contrail-vrouter-agent.log

Snippet of sample log message related to BFD session events