[Libvir] Re: Next features and target for development

[Anthony Liguori]

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?

For KVM, the guest isn't destroyed explicitly after a migration is 
successful.  Instead, the source guest is left in a paused state.  The 
main reason for not destroying the guest was so that a management tool 
could still interact with the guest's monitor to obtain statistics on 
the migration.  It's expected that the management tool will destroy the 
domain on the source machine whenever it is done working with it.

The KVM source guest is still resumable too so this doubles as a 
mechanism for forking VMs.  I think these are useful semantics that 
ought to be exposed.  With KVM, live migration is more generic.  You can 
use it to do light-weight checkpointing.

Regards,

Anthony Liguori