Libguestfs - Oct 2014 - conversion issue on NFS shares

Hi

T'm trying to convert XEN virtual machine image into raw. Source file is on
NFS export and destination is also on nfs export. (both exports are mounted
on migration servers RW access). I'm getting permission denied.
I have RW access to both exports - I can create, delete objects on both
exports from migration server. But when I copy img file onto migration
server local filesystem, conversion works, from local fs to nfs export.
However when I tried to run guestfish against file located on NFS - I'm
getting the same erro - Permission denied .

[root@kvm01 export]# virt-v2v -i disk migr01.img -o local -os /tmp
[   0.0] Opening the source -i disk migr01.img
[   0.0] Creating an overlay to protect the source from being modified
[   0.0] Opening the overlay
virt-v2v: error: libguestfs error: could not create appliance through
libvirt.

Try running qemu directly without libvirt using this environment variable:
export LIBGUESTFS_BACKEND=direct

Original error from libvirt: internal error: process exited while
connecting to monitor: 2014-10-16T14:25:13.729270Z qemu-kvm: -drive
file=/var/tmp/v2vovl60e1a0.qcow2,if=none,id=drive-scsi0-0-0-0,format=qcow2,cache=unsafe,discard=unmap:
could not open disk image /var/tmp/v2vovl60e1a0.qcow2: Could not open
backing file: Could not open '/mnt/xen01/export/migr01.img': Permission
denied
 [code=1 domain=10]

If reporting bugs, run virt-v2v with debugging enabled and include the
complete output:

  virt-v2v -v -x [...]
[root@kvm01 export]#


-- 

Artur Krzywdzinski

On Thu, Oct 16, 2014 at 04:34:03PM +0200, Artur Krzywdzinski
wrote:
> Hi
> 
> T'm trying to convert XEN virtual machine image into raw. Source file
is on
> NFS export and destination is also on nfs export. (both exports are mounted
> on migration servers RW access). I'm getting permission denied.
> I have RW access to both exports - I can create, delete objects on both
> exports from migration server. But when I copy img file onto migration
> server local filesystem, conversion works, from local fs to nfs export.
> However when I tried to run guestfish against file located on NFS - I'm
> getting the same erro - Permission denied .
> 
> [root@kvm01 export]# virt-v2v -i disk migr01.img -o local -os /tmp
> [   0.0] Opening the source -i disk migr01.img
> [   0.0] Creating an overlay to protect the source from being modified
> [   0.0] Opening the overlay
> virt-v2v: error: libguestfs error: could not create appliance through
> libvirt.
> 
> Try running qemu directly without libvirt using this environment variable:
> export LIBGUESTFS_BACKEND=direct
> 
> Original error from libvirt: internal error: process exited while
> connecting to monitor: 2014-10-16T14:25:13.729270Z qemu-kvm: -drive
>
file=/var/tmp/v2vovl60e1a0.qcow2,if=none,id=drive-scsi0-0-0-0,format=qcow2,cache=unsafe,discard=unmap:
> could not open disk image /var/tmp/v2vovl60e1a0.qcow2: Could not open
> backing file: Could not open '/mnt/xen01/export/migr01.img':
Permission
> denied
>  [code=1 domain=10]
This is a problem with libvirt (RHBZ#890291).  Follow the instructions
printed in the error message to make it work.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
Fedora Windows cross-compiler. Compile Windows programs, test, and
build Windows installers. Over 100 libraries supported.
http://fedoraproject.org/wiki/MinGW

On Thu, Oct 16, 2014 at 04:34:03PM +0200, Artur Krzywdzinski
wrote:
> Hi
> 
> T'm trying to convert XEN virtual machine image into raw. Source file
is on
> NFS export and destination is also on nfs export. (both exports are mounted
> on migration servers RW access). I'm getting permission denied.
> I have RW access to both exports - I can create, delete objects on both
> exports from migration server. But when I copy img file onto migration
> server local filesystem, conversion works, from local fs to nfs export.
> However when I tried to run guestfish against file located on NFS - I'm
> getting the same erro - Permission denied .
> 
> [root@kvm01 export]# virt-v2v -i disk migr01.img -o local -os /tmp
> [   0.0] Opening the source -i disk migr01.img
> [   0.0] Creating an overlay to protect the source from being modified
> [   0.0] Opening the overlay
> virt-v2v: error: libguestfs error: could not create appliance through
> libvirt.
> 
> Try running qemu directly without libvirt using this environment variable:
> export LIBGUESTFS_BACKEND=direct
> 
> Original error from libvirt: internal error: process exited while
> connecting to monitor: 2014-10-16T14:25:13.729270Z qemu-kvm: -drive
>
file=/var/tmp/v2vovl60e1a0.qcow2,if=none,id=drive-scsi0-0-0-0,format=qcow2,cache=unsafe,discard=unmap:
> could not open disk image /var/tmp/v2vovl60e1a0.qcow2: Could not open
> backing file: Could not open '/mnt/xen01/export/migr01.img':
Permission
> denied
>  [code=1 domain=10]
> 
> If reporting bugs, run virt-v2v with debugging enabled and include the
> complete output:
> 
>   virt-v2v -v -x [...]
> [root@kvm01 export]#
Finally I worked out what's going on here.

If your $HOME directly is on NFS, then you have to enable a couple of
SELinux booleans so that libvirt can write to it:

setsebool -P use_nfs_home_dirs on
setsebool -P virt_use_nfs on

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
libguestfs lets you edit virtual machines.  Supports shell scripting,
bindings from many languages.  http://libguestfs.org