Re: [Xen-devel] [PATCH] libxl: Disallow save or migrate when host devices are assigned to a guest.

[Jim Fehlig <jfehlig@xxxxxxxx>]

Dario Faggioli wrote:
> On Tue, 2015-04-14 at 20:15 -0600, Jim Fehlig wrote:
>   
>> Konrad Rzeszutek Wilk wrote:
>>     
>
>   
>>> -static bool
>>> -libxlDomainMigrationIsAllowed(virDomainDefPtr def)
>>> -{
>>> -    /* Migration is not allowed if definition contains any hostdevs */
>>> -    if (def->nhostdevs > 0) {
>>> -        virReportError(VIR_ERR_OPERATION_INVALID, "%s",
>>> -                       _("domain has assigned host devices"));
>>> -        return false;
>>> -    }
>>> -
>>> -    return true;
>>> -}
>>> -
>>>       
>> This function was created with the intention of adding more checks, e.g.
>> is the cpu and numa configuration migratable?
>>
>>     
> Only vaguely related to the patch, I know (sorry!), but if I can ask,
> what do you mean with "is the cpu and numa configuration migratable?"
>   

I was thinking about domXML such as

  <domain>
    ...
    <vcpu cpuset='0-8'>8</vcpu>
    <memory>62914560</memory>
    <maxMemory>104857600</maxMemory>
    <numatune>
      <memory mode='strict' nodeset='1-2'/>
    </numatune>
  ...
  </domain>

> I mean what NUMA configuration are we talking about, and when and under
> what circumstances would you consider it "migratable"?
>   

E.g. if a domain is configured to use memory allocated from certain numa
nodes, we'd want to make sure the dest has sufficient memory amongst
those nodes.

But these were just examples of things we may want to check before
starting the migration.  I suppose there are better examples wrt
storage, e.g. does the domain have an attached DVD, ...

Regards,
Jim


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