Reviewed: https://review.openstack.org/614008 Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=643f53f5e9544d6c98833b1ae3dd472602118a1f Submitter: Zuul Branch: master
commit 643f53f5e9544d6c98833b1ae3dd472602118a1f Author: Mohammed Naser <[email protected]> Date: Mon Oct 29 19:49:41 2018 +0100 libvirt: Avoid setting MTU during live migration if unset If there is a live migration of an instance that was launched before change Iecc265fb25e88fa00a66f1fd38e215cad53e7669, it would not have an mtu set and therefore it wouldn't have it in the XML. When live migrating, the mtu is added which changes the guest ABI[1], causing the live migration to fail. The failure occurs when trying to live migrate an instance that: - Launched before change Iecc265fb25e88fa00a66f1fd38e215cad53e7669 - It has not been rebooted (i.e. XML has not changed since) - It's using bridge/tap networking - Migration attempted after change Iecc265fb25e88fa00a66f1fd38e215cad53e7669 This patch prevents this by avoiding setting MTU if the running instance does not have one configured in its domain XML. [1]: https://bugzilla.redhat.com/show_bug.cgi?id=1449346 Closes-Bug #1800511 Change-Id: I6e2e6437a7c826dc425d8b353c38670d6eece0b5 ** Changed in: nova Status: In Progress => Fix Released ** Bug watch added: Red Hat Bugzilla #1449346 https://bugzilla.redhat.com/show_bug.cgi?id=1449346 -- You received this bug notification because you are a member of Yahoo! Engineering Team, which is subscribed to OpenStack Compute (nova). https://bugs.launchpad.net/bugs/1800511 Title: VMs with vif_type bridge/tap started before Rocky upgrade cannot be live migrated Status in OpenStack Compute (nova): Fix Released Status in OpenStack Compute (nova) rocky series: In Progress Bug description: In Rocky, the following patch introduced adding MTU to the network for VMs: https://github.com/openstack/nova/commit/f02b3800051234ecc14f3117d5987b1a8ef75877 However, this didn't affect live migrations much because Nova didn't touch the network bits of the XML during live migration, until this patch: https://github.com/openstack/nova/commit/2b52cde565d542c03f004b48ee9c1a6a25f5b7cd With that change, the MTU is added to the configuration, which means that the destination is launched with host_mtu=N, which apparently changes the guest ABI (see: https://bugzilla.redhat.com/show_bug.cgi?id=1449346). This means the live migration will fail with an error looking like this: 2018-10-29 14:59:15.126+0000: 5289: error : qemuProcessReportLogError:1914 : internal error: qemu unexpectedly closed the monitor: 2018-10-29T14:59:14.977084Z qemu-kvm: get_pci_config_device: Bad config data: i=0x10 read: 61 device: 1 cmask: ff wmask: c0 w1cmask:0 2018-10-29T14:59:14.977105Z qemu-kvm: Failed to load PCIDevice:config 2018-10-29T14:59:14.977109Z qemu-kvm: Failed to load virtio-net:virtio 2018-10-29T14:59:14.977112Z qemu-kvm: error while loading state for instance 0x0 of device ‘0000:00:03.0/virtio-net’ 2018-10-29T14:59:14.977283Z qemu-kvm: load of migration failed: Invalid argument I was able to further verify this by seeing that `host_mtu` exists in the command line when looking at the destination host instance logs in /var/log/libvirt/qemu/instance-foo.log To manage notifications about this bug go to: https://bugs.launchpad.net/nova/+bug/1800511/+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
