[Libguestfs] Error running virt-v2v

[Richard W.M. Jones]

On Mon, Mar 22, 2021 at 10:11:08AM +0000, Eoghan O'Hara wrote:
> Hi Richard,
> 
> I included -v and -x, and have attached the output below.

The reason is when we create the output, the target device is not
writable, apparently it's a read-only filesystem:

  [  65.4] Copying disk 1/1 to /datassd/3/libvirt/Appliances/kx-platform-vm-20210318-123942-sda (qcow2)
  ...
  libguestfs: trace: disk_create "/datassd/3/libvirt/Appliances/kx-platform-vm-20210318-123942-sda" "qcow2" 262144000000 "preallocation:sparse" "compat:1.1"
  libguestfs: command: run: qemu-img
  libguestfs: command: run: \ create
  libguestfs: command: run: \ -f qcow2
  libguestfs: command: run: \ -o preallocation=off,compat=1.1
  libguestfs: command: run: \ /datassd/3/libvirt/Appliances/kx-platform-vm-20210318-123942-sda
  libguestfs: command: run: \ 262144000000
  qemu-img: /datassd/3/libvirt/Appliances/kx-platform-vm-20210318-123942-sda: Could not create file: Read-only file system

You're using “-o libvirt -os Appliances” which means it's trying to
use a libvirt storage pool called “Appliances”, which presumably is
mapped to /datassd/3/libvirt/Appliances in your case.  You can find
out about libvirt storage pools here:

  https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/virtualization_deployment_and_administration_guide/sect-managing_guest_virtual_machines_with_virsh-storage_pool_commands#section-virsh-pool-info

Might be best to use “-o local -os /some/writable/directory” and then
you will end up with a libvirt XML file and the raw disks, and you can
choose what to do with them.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
virt-builder quickly builds VMs from scratch
http://libguestfs.org/virt-builder.1.html