Public bug reported: 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 ** Affects: neutron Importance: Undecided Status: 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 : yahoo-eng-team@lists.launchpad.net Unsubscribe : https://launchpad.net/~yahoo-eng-team More help : https://help.launchpad.net/ListHelp