We've came across this problem as well.
We have 4 Glance nodes, with the images mounted on an NFS volume. One of the Glance instances went down, and it failed mounting the NFS when it rebooted. We started having VMs with more than one port assigned (showing more than one IP per VM in Horizon.)
Seems to us that Nova should tell Neutron, either to delete the unused port, or update it instead of creating a new one.
We've came across this problem as well.
We have 4 Glance nodes, with the images mounted on an NFS volume. One of the Glance instances went down, and it failed mounting the NFS when it rebooted. We started having VMs with more than one port assigned (showing more than one IP per VM in Horizon.)
Seems to us that Nova should tell Neutron, either to delete the unused port, or update it instead of creating a new one.