On Mon, Mar 09, 2009 at 11:14:56PM +0900, Matt McCowan wrote:
OK. Another run at producing a function that helps the likes of me backup my kvm Windows servers. 'virsh checkpoint domain file [script]' is what the following patch set (against cvs) enables. Modelled on the virDomainSave function it takes an optional script which it will execute (and pass the name of the domain as an argument) while the domain is paused, then resume the domain.
Okay, I quickly looked at the patch and the new API, so no stylistic review at this point but more a general feedback. I appreciate the completeness of the patch (only bit missing is filling up the virsh man page with the new option) I think this can help administrators in a controlled situation, but I'm hoping a real snapshotting API will be possible at some point where libvirt goes though the list of storage resources used by the domain and properly make a snapshot using a storage API or return an error if that's not possible. This looks more as a script extension to virDomainSave/Restore than really a snapshotting API as I would like libvirt to get at some point. To me it doesn't implement snapshotting, it implement running a script on a frozen domain. There is a lot of issues with that: - the script need to be in place and there is no hint of what it may contain - what the script does is unbounded, there is a potential very serious security issue there - this does not garantee sucess of the operation and in case of failure the script can't even propagate back an error code and description In my opinion this is a bit too ad-hoc to be turned into a full API maintained forever, and I'm worried about remote execution capabilities this opens up. I really hope we will have one day a real checkpointing API in libvirt, but that requires making more progresses on the storage management side. Still thanks for sending the patches, even if I think this is not ripe for inclusion, it reminds us that snapshotting is a big issue and need to be taken care of !
By the by stability is coming along nicely since 0.6.0. Thanks!
Yeah, there were a lot of changes, and bugs are ironed out progressively. Check the version from CVS/git/snapshot to get the latest changes as usual, Daniel -- Daniel Veillard | libxml Gnome XML XSLT toolkit http://xmlsoft.org/ daniel@veillard.com | Rpmfind RPM search engine http://rpmfind.net/ http://veillard.com/ | virtualization library http://libvirt.org/