Open Stack

On 24 February 2014 22:14, Chris Friesen <chris.friesen at windriver.com> wrote:
> I'm looking at the live migration rollback code and I'm a bit confused.
>
> When setting up a live migration we unconditionally run
> ComputeManager.pre_live_migration() on the destination host to do various
> things including setting up networks on the host.
>
> If something goes wrong with the live migration in
> ComputeManager._rollback_live_migration() we will only call
> self.compute_rpcapi.rollback_live_migration_at_destination() if we're doing
> block migration or volume-backed migration that isn't shared storage.
>
> However, looking at ComputeManager.rollback_live_migration_at_destination(),
> I also see it cleaning up networking as well as block device.
>
> What happens if we have a shared-storage instance that we try to migrate and
> fail and end up rolling back?  Are we going to end up with messed-up
> networking on the destination host because we never actually cleaned it up?

I had some WIP code up to clean that up, as part as the move to
conductor, its massively confusing right now.

Looks like a bug to me.

I suspect the real issue is that some parts of:
self.driver.rollback_live_migration_at_destination(ontext, instance,
                        network_info, block_device_info)
Need more information about if there is shared storage being used or not.

John