[pve-devel] saving kvm command line for migration

[Stefan Priebe - Profihost AG]

Am 19.02.2014 11:57, schrieb Dietmar Maurer:
>> can somebody please explain to be what's the problem with saving the kvm
>> command of the last start as JSON array inside the conf file and use that one
>> for migration?
> 
> I think there is no guarantee that the same configuration generates the same command line
> on different hosts.

Yeah think the same.

>> I'm seeing several problems with migration and modifing the configuration
>> while the VM is running.
> 
> There are 2 possible solutions:
> 
> A. store the configuration at VM start (and use that configuration to start after migration)
> B. Do not allow to modify the configuration while the VM is running (and hotplug disabled)
> 
> I think B.) is easier to implement.

B.) is to unflexible. Even it might be easier to implement. We have the
same problem for snapshots. We just save the config and HOPE that the
newly generated command line matches the old one.

The bigges problem is hotplug where we have to modify the already saved
command line.

Greets,
Stefan