Re: [Kimchi-devel] [RFC] Guest cloning

On 10/07/2014 12:27 PM, Christy Perez wrote: > I'm guessing that Brent and Adam already discussed virt-clone, so I'm > curious as to the reasons why that's not an option. I've found that > virt-install (the package that includes it) has (on Fedora 20) a > dependency on virt-manager-common. That, and maybe it's not available > for all distros? Maybe it wouldn't copy disks into the right places? It was what I had in mind. We could investigate on how virt-manager and virt-clone do it.

> Thanks, > > - Christy > > On 10/06/2014 08:28 AM, Crístian Viana wrote: >> On Sex, 2014-10-03 at 08:28 -0500, Brent Baude wrote: >>> At one point Adam had really suggested we look at how guests are >>> defined >>> and changed. In particular, straight copies of XML and or straight >>> edits of XML could lead (after time) to the XML digressing into >>> something libvirt might not understand at some point. >> Do you remember exactly what in the XML file digressed like that? It >> would be very nice to know it. >> >>> To prevent this sort of problem, we thought that each time a guest is >>> edited, the XML is created entirely anew but of course using the same >>> values. >> I first thought about doing that as well, but I'm afraid our own new XML >> does not have all the features the original VM had. For example, on >> Kimchi we don't have support to custom CPU flags yet (i.e. we don't >> add/change those values). What would happen if we clone an existing VM >> with "unsupported" (as of Kimchi) features like that one? If we don't >> know about them and we're creating a new XML from scratch, we're only >> going to add what we're aware of. And I think this could make our >> cloning feature very unrealiable. Reading an existing XML and redefining >> it will always propagate whatever there is in that VM. As long as the >> XML doesn't get digressed, of course. >> >> Here's one current scenario for me. I have a few VMs on my laptop which >> I use to test Kimchi on them. As they need to be a hypervisor in order >> to run Kimchi, I have to add a few CPU flags to their XML descriptors >> which allow them to be a hypervisor (i.e. those Intel/AMD virtualization >> parameters). I do that manually using "virsh edit". If I clone one of my >> VMs using the approach above and it recreates their XML files from the >> beginning, AFAIU, the CPU flags will not be copied along. And I'd be >> very unsatisfied because the clone feature dropped a few things of my >> original VM while cloning. >> >> If we know what are the problems you had with Adam while copying the XML >> files over and over, maybe it' easier to fix them than to try to create >> a new one with all the libvirt's features, including the ones Kimchi is >> still not aware of. >> >>> About a month ago I had a working version of this in draft >>> form. >>> Would anyone be interested in reviewing it and or adding to it prior to >>> implementing the clone function? If so, ping me on IRC and I'll get >>> you >>> a copy of the patch. >> I am interested on it! I'll ping you then. >> > _______________________________________________ > Kimchi-devel mailing list > Kimchi-devel(a)ovirt.org > http://lists.ovirt.org/mailman/listinfo/kimchi-devel