MTU setting feature conflicts with minimum Qemu version
| Affects | Status | Importance | Assigned to | Milestone | |
|---|---|---|---|---|---|
| | OpenStack Compute (nova) |
Undecided
|
Sahid Orentino | ||
Bug Description
Afaics Nova breaks with Qemu versions newer than the minimum required version.
The change at [1] added support for setting MTU size in the libvirt settings of guests. This code checks for a minimum libvirt version 3.3.0 [2] but not for a required Qemu version.
The Nova minimum required Qemu version is 2.5 currently according to [3] (which is the latest release available with Ubuntu Xenial 16.04).
Afaics Qemu added support with release 2.9 [4] which means versions 2.5 to 2.8 of Qemu will break despite being listed as supported iiuc.
This issue broke our CIs. For verification i checked the master commit [5] which merged prior to [1] which tested ok with our CI.
The fix probably is to simply add a check for the minimum required Qemu version beside the minimum required libvirt version.
[1] https:/
[2] https:/
[3] https:/
[4] https:/
[5] https:/
Fix proposed to branch: master
Review: https:/
| Changed in nova: | |
| assignee: | nobody → sahid (sahid-ferdjaoui) |
| status: | Confirmed → In Progress |
| tags: | added: libvirt queens-backport-potential |
Reviewed: https:/
Committed: https:/
Submitter: Zuul
Branch: master
commit e2d7189f4ff7e4a
Author: Sahid Orentino Ferdjaoui <email address hidden>
Date: Mon Jul 2 17:42:05 2018 +0200
libvirt: add qemu version check when configuring mtu for network
This adds a QEMU check when configuring MTU for ethernet and bridge
interface types. When creating and configuring tap devices, libvirt is
setting MTU but also configures the virtio-net devices to let it
discovers the MTU used. This QEMU 'host_mtu' option is supported by
QEMU version 2.9 and more.
Closes-Bug: 1779626
Change-Id: I55cf259c715ba1
Signed-off-by: Sahid Orentino Ferdjaoui <email address hidden>
| Changed in nova: | |
| status: | In Progress → Fix Released |
Fix proposed to branch: stable/queens
Review: https:/
Reviewed: https:/
Committed: https:/
Submitter: Zuul
Branch: stable/queens
commit 509e0a030397887
Author: Sahid Orentino Ferdjaoui <email address hidden>
Date: Mon Jul 2 17:42:05 2018 +0200
libvirt: add qemu version check when configuring mtu for network
This adds a QEMU check when configuring MTU for ethernet and bridge
interface types. When creating and configuring tap devices, libvirt is
setting MTU but also configures the virtio-net devices to let it
discovers the MTU used. This QEMU 'host_mtu' option is supported by
QEMU version 2.9 and more.
Closes-Bug: 1779626
Change-Id: I55cf259c715ba1
Signed-off-by: Sahid Orentino Ferdjaoui <email address hidden>
(cherry picked from commit e2d7189f4ff7e4a
| tags: | added: in-stable-queens |
This issue was fixed in the openstack/nova 18.0.0.0b3 development milestone.
This issue was fixed in the openstack/nova 17.0.6 release.
It's not really clear why libvirt is also trying to configure host_mtu for virtio-net devices and why it returns an error if the QEMU version does not support that setting. libvirt should probably just create the tap device and configure it. Then configuring virtio-net should be a nice to have.
I'm currently discussing with community but we will have to probably provide a fix/workaround.