Re: [libvirt] [PATCH v2] domain_conf: skip boot order check of CD-ROM or floppy device when change-media
At 2018-01-11 21:36:29, "Ján Tomko" <jtomko(a)redhat.com> wrote:
On Thu, Jan 11, 2018 at 06:16:37PM +0800, Chen Hanxiao wrote:
>From: Chen Hanxiao <chenhanxiao(a)gmail.com>
>
>If we insert or eject a CD-ROM/floppy device by:
> 'virsh change-media VM --eject/--insert some.iso --live',
>and the original CD-ROM device was configed with a boot order,
>we may get:
> unsupported configuration: boot order 2 is already used by another device
>
>We just updated 'source file' section rather than hotplug a new device.
>This check should be skipped in this case.
>
Attempting to change the boot index on update won't work and should be
forbidden, as stated in the review for v1:
https://www.redhat.com/archives/libvir-list/2018-January/msg00178.html
My case is not try to change boot index, but to change-media:
1) boot a VM with a CD-ROM, a centos7.1 ISO inside
2) change iso from centos7.3 to centos7.2 by:
# change-media c72 hda /media/b/ISO/CentOS-7-x86_64-DVD-1611.iso --live
Successfully updated media.
This works and we can see cd-rom changed inside guest.
But if we had <boot order>
<disk type='file' device='disk'>
<driver name='qemu' type='qcow2'/>
<source file='/media/b/IMG/c72.qcow2'/>
<target dev='vda' bus='virtio'/>
+ <boot order='1'/>
<address type='pci' domain='0x0000' bus='0x00'
slot='0x07' function='0x0'/>
</disk>
<disk type='file' device='cdrom'>
<driver name='qemu' type='raw'/>
<source file='/media/b/ISO/CentOS-7-x86_64-DVD-1511.iso'/>
<target dev='hda' bus='ide'/>
<readonly/>
+ <boot order='2'/>
<address type='drive' controller='0' bus='0'
target='0' unit='0'/>
</disk>
Then change media will fail:
# change-media c72 hda /media/b/ISO/CentOS-7-x86_64-DVD-1511.iso --live
error: Failed to complete action update on media
error: unsupported configuration: boot order 2 is already used by another device
This is a common case when install OS with multiple DVDs,
or change DVD media when guest is active.
>Signed-off-by: Chen Hanxiao <chenhanxiao(a)gmail.com>
>---
>v2:
[...]
>+ /* Skip check for insert or eject CD-ROM device */
>+ if (disk_device == VIR_DOMAIN_DISK_DEVICE_FLOPPY ||
>+ disk_device == VIR_DOMAIN_DISK_DEVICE_CDROM) {
Even though cdrom hotplug is not supported by libvirt, assuming that
we're dealing with an update just because of the device type is wrong:
https://www.redhat.com/archives/libvir-list/2018-January/msg00180.html
virDomainDefCompatibleDevice should be aware of the operation (attach
vs. update) and behave accordingly (forbid duplicit bootindexes for
attach and a bootindex change for update)
As we can successfully 'virsh change-media' without <boot order> of CD-ROM
device,
should we forbid this case for a live domain?
Regards,
- Chen