Comment 8 for bug 1556549

I can reproduce this easily on devstack.

ubuntu@devstack:~/devstack$ git branch -a
* master
  remotes/origin/HEAD -> origin/master
  remotes/origin/master
  remotes/origin/stable/kilo
  remotes/origin/stable/liberty
ubuntu@devstack:~/devstack$

Here is the script to make openvswitch to fail:-

#!/bin/bash

for i in `seq 1 350`;
do
    /usr/bin/ovsdb-client monitor Interface name,ofport,external_ids --format=json &
done

Once it spawns more than 330 ovsdb-client processes, openvswitch starts failing. Now, if you try to launch an instance, it errors out after some time with "no valid host" error. Even if you terminate the instance, you can see a leftover pair with two ends as qvo and qvb respectively. The more instances you launch, you will end up more number of veth pairs on your compute node.

root@devstack:/home/ubuntu# ifconfig | grep qvo
qvo4f07f296-d2 Link encap:Ethernet HWaddr 1e:bc:17:e4:3c:b8
root@devstack:/home/ubuntu#

Reboot of compute node is the only solution to get rid of those pairs, or removing them manually but it would be good if those stale entries are not left after the instance has failed and its removed.

Can you please let me know your views on the same?