[virt-tools-list] [RFC] virt-disk : a command line tool for modify domain XML's disk of inactive domains.

[KAMEZAWA Hiroyuki]

On Mon, 21 Feb 2011 17:20:56 -0700
Eric Blake <eblake at redhat.com> wrote:

> On 02/21/2011 05:04 PM, KAMEZAWA Hiroyuki wrote:
> > On Mon, 21 Feb 2011 08:17:30 -0700
> > Eric Blake <eblake at redhat.com> wrote:
> > 
> >> On 02/21/2011 01:23 AM, KAMEZAWA Hiroyuki wrote:
> >>> Hi, now, with qemu, virsh attach-disk doesn't work with inactive disks and
> >>> we need to edit XML with virsh edit.
> >>> IIUC, libvirt and virsh is designed as it is.
> >>
> >> Actually, libvirt should be patched to learn how to modify xml of
> >> inactive disks for qemu (it already can do it for xen, so the API is
> >> already present, it's just that no one has wired up that API for qemu).
> >>
> > 
> > Before starging this, I thought of that. I did this in python by 3 reasons.
> > 
> > 1. When we asked "Is it a spec that we cannot modify inactive domain ?" to
> >    a Redhat guy, he answered "it's a spec".
> >    Do you, maintainers, have some concensus about this ?
> 
> 'virsh attach-disk --persistent' is supposed to be able to modify an
> inactive domain.  If it doesn't do so for qemu, then that's because no
> one has yet implemented it correctly, which means libvirt has a bug that
> needs to be patched.  For example, see:
> 
> https://bugzilla.redhat.com/show_bug.cgi?id=669549
> 
> about 'virsh setmem --config' not working for qemu.
> 

Okay, I recognize it's a bug.

So, about networks/disks, 
 - qemudDomainAttachDeviceFlags() 
 - qemuDomainUpdateDeviceFlags()
 - qemudDomainDetachDeviceFlags()

..should be modified to handle XML with --persistent option ?



> > 
> > 2. virsh attach-disk doesn't seem to support misc. options. It doesn't have
> >    - boot_order
> >    - shareable
> >    - serial
> >    - io
> >    - error_policy
> >    etc...
> 
> If there's something that the libvirt API supports, but which virsh does
> not support, then that's a bug in virsh.  Please let us know about these
> usability deficiencies in virsh, since that is the right place to be
> patching it for use by all other shell-based tools, rather than
> reinventing a new tool by every user.
> 

We'll study what virsh does and start QEMU patches for these.

Hmm...cmdAttachDisk() etc...seems just to make XML by printf()..okay,
it seems not hard to modify virsh.c



Thanks,
-Kame