Open Stack

Thanks a lot  Franciszek !
I was indeed seeing the problem with a VM big 56 vcpus while I didn't see
the issue with a tiny instance

Thanks again !

Cheers, Massimo

On Fri, Oct 6, 2023 at 8:58 AM Franciszek Przewoźny <fprzewozny at opera.com>
wrote:

> Hi Massimo,
>
> We are using Ubuntu for our environments and we experienced the same issue
> during upgrade from Yoga/Focal to Yoga/Jammy. On Yoga/Focal cgroups_v1 were
> used, and cpu_shares parameter value was cpu count * 1024. From Jammy
> cgroups_v2 have been implemented, and cpu_shares value has been set by
> default to 100. It has hard limit of 10000, so flavors with more than
> 9vCPUs won't fit. If you need to fix this issue without stopping VMs, you
> can set cpu_shares with libvirt command: virsh schedinfo $domain --live
> cpu_shares=100
> for more details about virsh schedinfo visit:
> https://libvirt.org/manpages/virsh.html#schedinfo
>
> BR,
> Franciszek
>
> On 5 Oct 2023, at 21:17, smooney at redhat.com wrote:
>
> On Thu, 2023-10-05 at 16:53 +0200, Massimo Sgaravatto wrote:
>
> Dear all
>
> We have recently updated openstack nova on some AlmaLinux9 compute nodes
> running Yoga from 1:25.2.0 to 1.25.2.1. After this operation some VMs don't
> start anymore. In the log it is reported:
>
> libvirt.libvirtError: invalid argument: shares \'57344\' must be in range
> [1, 10000]\n'}
>
> libvirt version is 9.0.0-10.3
>
>
> A quick google search suggests that it is something related to cgroups and
> it is fixed in libvirt >= 9.1 (which is not yet in the almalinux9 repos).
> Did I get it right ?
>
> not quite
>
> it is reated to cgroups but the cause is that in cgroups_v1 the maxvlaue
> of shares
> i.e. cpu_shares changed form make int to 10000 in cgroups_v2
> so the issue is teh vm requested a cpu share value of 57344 which is not
> vlaid on an OS
> that is useing cgroups_v2 libvirt will not clamp the value nor will nova.
> you have to change the volue in your flavor and resize the vm.
>
>
>
>
> Thanks, Massimo
>
>
>
>
>
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