Re: [PATCH] qemuDomainChangeDiskLive: Modify 'startupPolicy' before changing source

On Monday, 13 September 2021 13:30:45 CEST Nir Soffer wrote: > On Mon, Sep 13, 2021 at 11:04 AM Peter Krempa <pkrempa(a)redhat.com&gt; wrote: > > On Fri, Sep 10, 2021 at 22:04:01 +0300, Nir Soffer wrote: > > > On Fri, Sep 10, 2021 at 4:35 PM Peter Krempa <pkrempa(a)redhat.com&gt; wrote:

> > On another note, I don't quite understand though why oVirt actually even > > uses startup policy in the first place. Since oVirt is already doing a > > pretty complicated storage management, checking whether the image file > > exists is a trivial operation. > > In oVirt we know that the image exists since we prepare it before > starting the VM > (e.g. activate logical volume), and we will fail the operation if the > disk does not > exists, so I think this attribute is not needed for our use case and > it should be > removed. +1 > > Similarly, when migrating you can use the destination XML (which can be > > optionally used with the migration API) allows you to update storage > > source and even provide empty storage for a cdrom. This can be used to > > update paths to storage too. This allows superior flexibility when > > compared to startup policy. > > Even if we remove startupPolicy in new oVirt version, we have to > support migration > from an older version using startupPolicy in the xml. What is the problem here? The issue happens only when you try to change the CD, not during the migration, so there shouldn't be any problem (I also tried it now and I can migrate VM with block-based CD without any issue). The issue is there only when VM is started with empty CD or file-based CD, as in these cases we added startupPolicy into the XML.