Re: [PATCH v2 01/27] migration: Network Failover can't work with a paused guest

[Michael S. Tsirkin]

On Thu, Dec 03, 2020 at 11:43:41AM +0000, Dr. David Alan Gilbert wrote:
> Another way to solve this would be to remove the unplugging from the
> migration layer and leave it as a problem for the management layer to do
> the unplug.

Daniel described the problem with modular management tools which expect
pausing or slowing down guest to cause migration to converge.

Point is, it actually *will* make it converge but only if you
pause it after unplug.

As it is, these tools fundamentally can not handle failover
requiring guest cooperation. Moving code between layers won't help.
Introducing failure modes as this patch does won't help either
especially since Daniel wrote there are countless tools like this.
We just break them all but have no resources to fix them,
this does not help at all.

We can just leave the situation as is.

Or if we do want to be nice to these tools, how about we
unpause the guest until unplug, then pause it again?
This actually addresses the problem instead of
shifting the blame, does it not?

-- 
MST