On 7/16/21 8:51 AM, Daniel P. Berrangé wrote:
On Fri, Jul 16, 2021 at 09:49:40PM +0900, Motohiro Kawahito wrote:
From: "Daniel P. Berrangé" <berrange@xxxxxxxxxx>
To: Motohiro Kawahito <JL25131@xxxxxxxxxx>
Cc: libvir-list@xxxxxxxxxx
Date: 2021/07/16 17:22
Subject: [EXTERNAL] Re: Question about skipping
virDomainDiskDefAssignAddress
On Fri, Jul 16, 2021 at 01:01:50PM +0900, Motohiro Kawahito wrote:
From: "Daniel P. Berrangé" <berrange@xxxxxxxxxx>
To: Motohiro Kawahito <JL25131@xxxxxxxxxx>
Cc: libvir-list@xxxxxxxxxx
Date: 2021/07/16 00:42
Subject: [EXTERNAL] Re: Question about skipping
virDomainDiskDefAssignAddress
With the exception of paravirtualized Xen guests, this field in
libvirt XML is *completely* independant of the guest assigned
device name.
eg the XML might say /dev/vda, but the guest might decde to
call it /dev/sda, or /dev/whatever or really absolutely
anything.
Thank you very much for this information! I understand it.
However, I don't understand how we can pass the target device
information
(e.g. 0A80) without an error. Do you know how to do it?
My question was not good, so I opened another thread (How do we
specify
disk device names for non-Linux VMs in XML?).
There is nothing that needs passing. The guest OS decides its naming
however it wants to.
We need to control device number from user. This device number would be
used later, such as detach-disk. Can we pass device number from outside?
Detach-disk requires the same information that is provided when the
disk is first configured in libvir. This is completely separate to the
device number / name seen inside the guest.
To expand on that, in the case of detaching a disk, you could 1) provide
the target dev in the XML you give to "virsh detach-device", 2) give the
target dev name that you provided in the original XML when you call
"virsh detach-disk", or 3) you could specify a custom alias in the
original XML ("<alias name='ua-somename'/>" - note that the leading
"ua-" is *required* for a custom alias name) and then give that same
alias to "virsh detach-device-alias". All three will allow you to
reliably select the disk you want, and have the same result.
