[libvirt-users] [qemu-kvm] Network bandwidth limits via libvirt

[Laine Stump]

On 08/12/2014 01:37 PM, Romain Hardouin wrote:
> Hi all,
>
> I try to understand why the interface bandwidth limits are not applied to my Ubuntu 12.04 VM (qemu-kvm driver) and I would need some insights.
> I spawn my VM with OpenStack and when I issue a dumpxml on my domain, I can see that bandwidth limits are set:
>
> <interface type='ethernet'>

What is the reason for using <interface type='ethernet'> instead of
type='bridge'? In general, type='ethernet' is intended to be used only
as a last resort if a more supported type (pretty much anything else,
except 'user') can't do what is needed.

That is the reason you're not seeing the effects of the <bandwidth>
element - <bandwidth> only affects interface types of 'bridge',
'network', or 'direct' (source: I just checked the code). In theory
there's no reason I know of that we shouldn't make it work on
type='ethernet', but due to the relative "unsupportedness" of
type='ethernet', nobody has noticed before now.