openstack team mailing list archive

[Jay Pipes <jaypipes@xxxxxxxxx>]

On 07/09/2012 09:35 AM, John Garbutt wrote:
> Renuka and I are looking at proposing a blueprint to try and sort out some of this confusion.
> 
> I think this is the current situation:
> - historically XenAPI had migrate, Libvirt had live migrate
> - But by end of Folsom we should have both having both

Yes, but what is the difference between the two?

> - Live migration was originally only nova-manage controlled
> - Migrate is useful, but requires things like passwordless ssh
> - We could re-implement migrate as snapshot and restart

This seems entirely reasonable.

> - Above is also true for Resize

That is actually how it already happens, with the CONFIRM_RESIZE state
acting as the quiescence point for the operation.

> - But there may be billing implications for the above changes
> - Live-migrate is more useful than migrate

Why? :)

> - But live-migrate not always possible (miss matched CPUs, etc)
> - Ideally we would have single migrate/live-migrate API 

This would be my preference. The way it stands today is entirely confusing.

> Possible first steps for Folsom:
> - Extend the migrate API to support a "live" and "live-block" migration options

Please explain these differences.

> - Maybe add "live with fallback to non-live" option

Again, need to know what the difference is you envision here?

> - Maybe above should be the default, add a "non-live" option
> - Fully document the expanded migrate API for Folsom

Oh, definitely. :)

Best,
-jay

> Does this sound reasonable?
> 
> Cheers,
> John
>