[libvirt] Question about migration max downtime in domXML

[Jim Fehlig]

Daniel P. Berrange wrote:
> On Tue, Jan 20, 2015 at 11:00:26AM -0700, Jim Fehlig wrote:
>   
>> Hi All,
>>
>> I've had a few user requests to add migration max downtime to the domain
>> XML.  IIRC, this was discussed on the list quite some time ago, but I'm
>> unable to find it in the archives.  My recollection is that max downtime
>> is considered a tunable vs config and as such not included in the
>> domXML.  But domXML does contain quite a few tunables, so perhaps my
>> memory is incorrect.  Does anyone recall the details?  I'd be happy to
>> work on this if folks find it acceptable.
>>     
>
> It isn't so much about tunables vs config - rather it is about virtual
> machine configuration vs API parameters. The various tunables we have
> are all things related to configuration of the virtual machine, where
> as the migration downtime is not really guest configuration data.
>   

Agreed.

> When you start moving management API parameters into the guest XML
> it makes the operation of the API less predictable, because you
> don't know what the semantics will be, without first consulting
> the guest XML settings that might affect the API.
>   

Yes, good point.  Thanks for clarifying!

Regards,
Jim