Re: A migration framework for external devices

["Mike D. Day" <ncmike@us.ibm.com>]

Stefan Berger wrote:
> Also what the plugins would need to do is lock the system so that once the 
> migration of VM A is starting no other migrated virtual machine B has 
> altered the state into a contradictory state that prevents migration of A. 
> I think one of the aspects of migration is to look at the target system 
> first and see whether one can migrate into it, then lock it to its state 
> (or do that at the same time) and then start the migration. Basically 
> migration needs to be 'atomic'.

Yes this is the key point. With the framework in place it would be a 
nice thing to do "dry runs" on the target. That is, do everything but 
actually migrate the domain. That way you could check that all the 
devices can be configured correctly, etc. In other words, verify the 
platform ahead of time. Get a high confidence in the target before 
attempting the migration.

> 
> I would have let the plugins implement their own protocol that suits their 
> needs and the framework just provides a lower level transport protocol for 
> dispatching messages to the plugins. At least that was my initial 
> thinking. Not sure whether RPC is necessary here.

Yeah, I'm not sure either the more I consider things. If it can save 
time and work, I'm for it.

Mike