The race condition still exists. Neutron happens to delete the bridge [1] between plug_vifs (ensure_bridge) [2] and _create_domain [3] if your instance is the only one using the bridge.
I locally fix it by disabling remove_empty_bridges and using a cron to delete empty bridges instead. [1] https://github.com/openstack/neutron/blob/6cf92011143eb55adda180ffac91886566fc7826/neutron/plugins/linuxbridge/agent/linuxbridge_neutron_agent.py#L926 [2] https://github.com/openstack/nova/blob/f9e664f1b6521dd7d5c02cd803e376e8abdf9c30/nova/virt/libvirt/driver.py#L4383 [3] https://github.com/openstack/nova/blob/f9e664f1b6521dd7d5c02cd803e376e8abdf9c30/nova/virt/libvirt/driver.py#L4390 ** Changed in: neutron Status: Invalid => New -- You received this bug notification because you are a member of Yahoo! Engineering Team, which is subscribed to neutron. https://bugs.launchpad.net/bugs/1328546 Title: Race condition when hard rebooting instance Status in OpenStack Neutron (virtual network service): New Bug description: Condition for this to happen: ====================== 1. Agent: neutron-linuxbridge-agent. 2. Only 1 instance is running on the hypervisor that belong to this network. 3. Timing, it's a race condition after all ;-) Remarked behavior: ================ After hard reboot instance end up in ERROR state and the nova-compute log an error saying that: Cannot get interface MTU on 'brqf9d0e8cf-bd': No such device What happen: =========== When nova do a hard reboot, the instance is first destroyed, which imply that the tap device is deleted from the linux bridge (which result to an empty bridge b/c of 2 condition above), than re-created afterward, but in between neutron-linuxbridge-agent may clean up this empty bridge as part of his remove_empty_bridges()[1], but for this error to happen neutron-linuxbridge-agent should do that after plug_vifs()[2] and before domain.createWithFlags() finish. [1]: https://github.com/openstack/neutron/blob/stable/icehouse/neutron/plugins/linuxbridge/agent/linuxbridge_neutron_agent.py#L449. [2]: https://github.com/openstack/nova/blob/stable/icehouse/nova/virt/libvirt/driver.py#L3648-3656 To manage notifications about this bug go to: https://bugs.launchpad.net/neutron/+bug/1328546/+subscriptions -- Mailing list: https://launchpad.net/~yahoo-eng-team Post to : [email protected] Unsubscribe : https://launchpad.net/~yahoo-eng-team More help : https://help.launchpad.net/ListHelp
