<div dir="ltr"><div class="gmail_default" style="font-size:small;color:#444444">Hello Danny,</div><div class="gmail_default" style="font-size:small;color:#444444"><br></div><div class="gmail_default" style="font-size:small;color:#444444">I am actually using Broadwell-noTSX-IBRS on all the servers but I have seen that some flags are not there in the older servers.</div><div class="gmail_default" style="font-size:small;color:#444444"><br></div><div class="gmail_default" style="font-size:small;color:#444444">The flags below to be specific.</div><div class="gmail_default" style="font-size:small;color:#444444"><br></div><div class="gmail_default" style="font-size:small;color:#444444"><span style="font-size:11pt;line-height:107%;font-family:Calibri,sans-serif;color:black">hwp hwp_act_window hwp_pkg_req </span><br></div><div class="gmail_default" style="font-size:small;color:#444444"><br></div><div><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div><font face="arial, sans-serif">Regards</font></div><div><font face="arial, sans-serif"><br></font></div><div dir="ltr"><font face="arial, sans-serif">Tony Karera</font></div><div dir="ltr"><br></div><div><br></div></div></div></div></div></div></div><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, Sep 1, 2023 at 4:05 PM <<a href="mailto:smooney@redhat.com">smooney@redhat.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">On Fri, 2023-09-01 at 14:56 +0200, Karera Tony wrote:<br>
> Hello Danny,<br>
> <br>
> Thanks for the feedback.<br>
> <br>
> use a lowest common denominator cpu_model : Does this mean changing the<br>
> servers ?<br>
<br>
it means tha tif you have a mix of cpus in the deployment you shoudl hardcod<br>
to the older of the diffent cpu models i.e skylake or whatever it may be in your case.<br>
<br>
<a href="https://docs.openstack.org/nova/latest/configuration/config.html#libvirt.cpu_models" rel="noreferrer" target="_blank">https://docs.openstack.org/nova/latest/configuration/config.html#libvirt.cpu_models</a><br>
<br>
[libvirt]<br>
cpu_mode=custom<br>
cpu_models=skylake<br>
<br>
in more recent release we replaced the older cpu_model with cpu_models with is a comma sperated<br>
list of models in prefernce order. i.e. nova will use the first cpu_modle in the list that work<br>
on the current host. not that while this give extra flexiblity it vs just using the oldest cpu model<br>
it does limit the set of hosts you can migrate too but means you can have better perfromance so its<br>
a tradeoff. performance vs portablity.<br>
<br>
the error you mentioned can also be caused by micorocode updates.<br>
intel remove TSX and MPX i beilve in the last 2 years form come of there cpus<br>
that breaks live migration if a vm was create with access to that cpu instruction<br>
<br>
the only way to resolve that is to cold migrate the guest.<br>
i.e. if a vm is currently booted with cpu_model X it cannot be modifed while the guest is running<br>
so you either need to update the config option and reboot all the vms or more particlaly update the config<br>
and then cold migrate them which will allow you to move the instnace(your orginal goal) while allowing<br>
the new cpu model to take effect.<br>
<br>
novas default for the cpu model when not set is with our default cpu_mode is host_model<br>
meaning whatever model best matches the current hosts cpu.<br>
<br>
that is the correct default in general but if you have mixed cpu generatiosn in your cloud its not ideal.<br>
<br>
hopefuly that helps<br>
<br>
> <br>
> Regards<br>
> <br>
> Tony Karera<br>
> <br>
> <br>
> <br>
> <br>
> On Fri, Sep 1, 2023 at 12:37 PM Danny Webb <<a href="mailto:Danny.Webb@thehutgroup.com" target="_blank">Danny.Webb@thehutgroup.com</a>><br>
> wrote:<br>
> <br>
> > It means that you have CPUs with incompatible flags or you've got<br>
> > differing kernel versions that expose different flags or you've got<br>
> > differing libvirt versions that expose different flags. You either need to<br>
> > use a lowest common denominator cpu_model or do a cold migration.<br>
> > ------------------------------<br>
> > *From:* Karera Tony <<a href="mailto:tonykarera@gmail.com" target="_blank">tonykarera@gmail.com</a>><br>
> > *Sent:* 01 September 2023 10:13<br>
> > *To:* openstack-discuss <<a href="mailto:openstack-discuss@lists.openstack.org" target="_blank">openstack-discuss@lists.openstack.org</a>><br>
> > *Subject:* Live migration error<br>
> > <br>
> > <br>
> > * CAUTION: This email originates from outside THG *<br>
> > ------------------------------<br>
> > Hello Team,<br>
> > <br>
> > I am trying to migrate instances from one host to another but I am getting<br>
> > this error.<br>
> > <br>
> > *Error: *Failed to live migrate instance to host "compute1". Details<br>
> > <<a href="http://10.10.13.31/admin/instances/#message_details" rel="noreferrer" target="_blank">http://10.10.13.31/admin/instances/#message_details</a>><br>
> > Migration pre-check error: Unacceptable CPU info: CPU doesn't have<br>
> > compatibility. 0 Refer to<br>
> > <a href="http://libvirt.org/html/libvirt-libvirt-host.html#virCPUCompareResult" rel="noreferrer" target="_blank">http://libvirt.org/html/libvirt-libvirt-host.html#virCPUCompareResult</a><br>
> > (HTTP 400) (Request-ID: req-9dfdfe2e-70fa-481a-bd3d-c2c76a6e93da)<br>
> > <br>
> > Any idea on how to fix this?<br>
> > <br>
> > Regards<br>
> > <br>
> > Tony Karera<br>
> > <br>
> > <br>
> > <br>
<br>
</blockquote></div>