[Libvir] Next features and target for development

[Daniel P. Berrange]

On Tue, Jul 10, 2007 at 11:49:34AM -0700, Dan Smith wrote:
> RJ> Some issues around migration which are up for discussion:
> 
> Something else to consider is whether or not we "undefine" hosts
> leaving one machine during a migration.  Last time I checked, Xen left
> a domain in "powered-off" state on the source.  It seems to make more
> sense to me for a migration to remove the shell domain from the source
> machine.
> 
> What will be the expected behavior here?

That's a good question really. There's definitely an argument to be made
that the guest shoud be undefined on the source to prevent its accidental
restart. 

If we wanted to make undefining after migrate compulsory, then doing it
as part of the virDomainMigrate call would make sense. If it was an optional
thing though, one could make use of a flag to virDomainMigrate, or simply
call virDomainUndefine explicitly.

Then again Xen is starting to get support for checkpointing of VMs - where
the original VM is left running after it has been saved (assume the disk
is snapshotted at time of save too). If you apply the concept of checkpoints
to migrate (which is using all the same code as save/restore in XenD), then
you could have this idea of migrating the VM & leaving it on the original
host too. 

Dan.
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