Sometimes it may happen that when you look in Contrail at the interfaces on a vRouter (on a Compute host) that some of them appear down. This you can also see on the Compute Node itself with vif –list. There can be some leftovers and this is the way to clean them up:

Temporary solution vif –del

If restarting the Compute Node though, then the problem is back as this does not delete the information from where the vRouter takes it upon startup.

Permanent solution

#delete from config directory from the vrouter agent container
#you connect to it of course with "docker exec -it <container ID from docker ps> /bin/bash"
rm /var/lib/contrail/ports/<port leftover>