Re: [Qemu-devel] [PATCH v3 0/5] Migration Deciphering aid

[Amit Shah]

On (Fri) 26 Dec 2014 [15:42:43], Alexander Graf wrote:
> Migration is a black hole to most people. One of the biggest reasons for
> this is that its protocol is a secret, undocumented sauce of code rolling
> around random parts of the QEMU code base.
> 
> But what if we simply exposed the description of how the format looks like
> alongside the actual migration stream? This is what this patch set does.
> 
> It adds a new section that comes after the end of stream marker (so that it
> doesn't slow down migration) that contains a JSON description of the device
> state description.
> 
> Along with this patch set also comes a python script that can read said JSON
> from a migration dump and decipher the device state and ram contents of the
> migration dump using it.
> 
> With this, you can now fully examine all glorious details that go over the
> wire when virtual machine state gets dumped, such as during live migration.
> 
> We discussed the approach taken here during KVM Forum 2013. Originally, my 
> idea
> was to include a special device that contains the JSON data which can be 
> enabled
> on demand. Anthony suggested however to just always include the description 
> data
> after the end marker which I think is a great idea.
> 
>   Example decoded migration: http://csgraf.de/mig/mig.txt
>   Example migration description: http://csgraf.de/mig/mig.desc.txt
>   Presentation: https://www.youtube.com/watch?v=iq1x40Qsrew
>   Slides: https://www.dropbox.com/s/otp2pk2n3g087zp/Live%20Migration.pdf

Nice to finally see this!

I guess you have a v4 coming soon?

                Amit