Comment 2 for bug 1367892

This bug is caused by a race condition between multiple neutron-server processes. If a number of vms are deleted in sequence, dvr_deletens_if_no_vms can return an erroneous response across the multiple processes. One neutron-server process thinks that it's port which is getting deleted is the last port on the host. It then deletes the router namespace. Another process can also think that it's port which is getting deleted is the last port on the host and attempts to delete the namespace but it's already gone having been deleted by the first process.

You can also create the opposite problem where multiple neutron-server process determine that no port is the last port on the host and as a result the router namespace never gets deleted.