On Sun, Apr 12, 2009 at 08:40:30AM +0200, Ján ONDREJ (SAL) wrote:
On Sat, Apr 11, 2009 at 11:41:14PM +0100, Richard W.M. Jones wrote:
>
http://et.redhat.com/~rjones/libguestfs/guestfs.3.html
I just looked against documentation. Can you build this for Fedora 10 i386?
Trying to rebuild your src.rpm in mock, but there an unmet dependencies.
What are the missing deps? You need to have febootstrap and a patched
version of fakechroot (from
http://et.redhat.com/~rjones/febootstrap/files/). Everything should
be covered by the BuildRequires in the src rpm, unless I've missed
something.
> I guess you understand that libguestfs doesn't work (or at
least, not
> consistently) with live virtual machines. You can certainly use
> libguestfs to take read-only peeks at the live VM's disk image, but
> the results you get won't necessarily be correct. Although in the
> virt-df case, which is similar, in practice the results are fine.
Yes, I know.
One extra thing I should mention is that I will need to patch qemu to
make this really safe. Qemu always tries to open the block devices
with O_RDWR [actually, I should say that the qemu code is very
confusing here, but at least this is what I think it does]. I need to
add a patch to qemu so that we can force it to open a drive in
O_RDONLY mode, eg:
qemu -drive foo,readonly
And then add the corresponding call guestfs_add_drive_ro.
[...]
I guess for the rest what you need is some sort of coordination of
guestfs & (eg) libvirt. Send to VM the 'lvcreate -s' command [how?],
sync, pause it, take snapshot, resume it. Coordinating that so you
get something consistent is going to be tricky.
Rich.
--
Richard Jones, Emerging Technologies, Red Hat
http://et.redhat.com/~rjones
Read my programming blog:
http://rwmj.wordpress.com
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