[libvirt-users] e1000 network interface takes a long time to set the link ready

[Ihar Hrachyshka]

On Fri, May 11, 2018 at 1:42 AM, Daniel P. Berrangé <berrange at redhat.com> wrote:
> On Thu, May 10, 2018 at 11:53:23AM -0700, Ihar Hrachyshka wrote:
>> Hi,
>>
>> In kubevirt, we discovered [1] that whenever e1000 is used for vNIC,
>> link on the interface becomes ready several seconds after 'ifup' is
>> executed, which for some buggy images like cirros may slow down boot
>> process for up to 1 minute [2]. If we switch from e1000 to virtio, the
>> link is brought up and ready almost immediately.
>>
>> For the record, I am using the following versions:
>> - L0 kernel: 4.16.5-200.fc27.x86_64 #1 SMP
>> - libvirt: 3.7.0-4.fc27
>> - guest kernel: 4.4.0-28-generic #47-Ubuntu
>>
>> Is there something specific about e1000 that makes it initialize the
>> link too slowly on libvirt or guest side?
>
> Try the e1000e device instead perhaps.

Thanks a lot for the suggestion, it works indeed. My understanding is
that it's the default NIC for q35 machines starting 2.12, so indeed
that's a great choice.

>
> If all other NIC models work, then this is likely to be a QEMU problem
> and should be reported as a bug to them. I notice you're running Fedora 27
> though, so before reporting bugs please try with latest upstream QEMU
> releases (2.12) to see if that's better

Thanks for the suggestion. I reported a bug here:
https://bugs.launchpad.net/qemu/+bug/1770724

I tried to reproduce it with 2.12 (built kubevirt stack with Fedora 29
packages) but I get some fundamental issues in the guest that block me
from reproducing the slow link ready bug (with the new qemu / libvirt
stack, I get kernel traces and irq interrupt error and no network link
at all in the guest). I hope my report against 2.10 would still fit
their bug report requirements.

Thanks again,
Ihar