[virt-tools-list] virt-manager get_xml inactive

[Cole Robinson]

On 03/11/2011 12:51 AM, Stephen Marron wrote:
> Hi,
> 
> Im looking for some feedback on how virt-manager should display the
> inactive/active xml details of a running virtual machine...
> 
> At the moment when a user views the basic details of a running virtual
> machine, the code will call get_xml() which defaults to retrieving the
> active xml state.
> 
> If a change is made ie we update the description field of the _running_
> machine to say "apache server" instead of "template", then hit apply,
> the user will get a message saying that some changes require a guest
> reboot, they click ok, the xml now looks like this:
> 
> Active xml still says "template"
> Inactive xml says "apache server"
> 
> Now if the user closes the details view then reopens it, without
> rebooting the virtual machine, we will reload the active xml and tell
> the user that the description is "template", this tends to be
> non-intuitive and confusing to the user...
> 
> Any thoughts on how this should be handled?
> 
> I dont think that we should _always_ display the inactive xml state, but
> i also dont think that the current method of _always_ displaying the
> active xml state is correct...
> 
> maybe certain fields (ie description) should always show the inactive
> xml state if its different, and the rest of the fields should always
> show the active state?
> 
> Thoughts?
> 

Interaction between hotplug (can change the running VM config) and
non-hotplug operations is confusing in virt-manager. Truthfully the best
solution would probably be to only allow changing parts of a running VM
that will take effect immediately, but to cleanly expose that in the UI
would be some work.

description is one of the few outliers here: by definition it's not
supposed to have any impact on a VM configuration, so there isn't really
any concept of hotplug. I guess you can make the argument that the
inactive description is always the canonical one. And there is certainly
value in allowing users to change the description for a running VM,
which we can fake if we always show the inactive desc.

One possible downside is that what shows up in virt-manager may not
match what a user sees if they do virsh dumpxml for a running guest, but
I don't think that's a big deal. So i've pushed a fix:

http://git.fedorahosted.org/git?p=virt-manager.git;a=commit;h=2e9c2ff92c917963de1e2bfcf0b7133c4ef52a83

Thanks,
Cole