Libguestfs - Jun 2011 - Comment on libguestfs code in https://bitbucket.org/swamiyeswanth/pyti

Yeswanth, I'm looking at:

https://bitbucket.org/swamiyeswanth/pyti/src/2b3a7401eccf/diskhandler.py
from this thread: http://librelist.com/browser//pyti/2011/6/13/disk-handler/

(1) I don't think the code you posted will work unless you move line
23 ('launch') up to just after you've added the drive (after line
12).

(2) You probably don't want to use 'add_drive'.  This deprecated
function has a potential vulnerability, although it will only affect
you if you are modifying untrusted raw-format guests.  The suggested
replacement is 'add_drive_opts' (which also has more features).

http://libguestfs.org/guestfs.3.html#guestfs_add_drive
http://libguestfs.org/guestfs.3.html#guestfs_add_drive_opts
https://bugzilla.redhat.com/642934

(3) Instead of using 'mount', use 'mount_options'.  The
'mount' call
adds some flags to the mountpoint which are not very useful and also
make disk writes very slow.

http://libguestfs.org/guestfs.3.html#guestfs_mount
http://libguestfs.org/guestfs.3.html#guestfs_mount_options
http://libguestfs.org/guestfs.3.html#libguestfs_gotchas

(4) After line 33 ('umount_all') you should also call
'self.disk_fs.sync()' which causes the libguestfs drive to be fully
synced.  Alternatively you can delete the handle ('del self.disk_fs')
which assuming no other references are being held will do the same
thing.

HTH,

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
libguestfs lets you edit virtual machines.  Supports shell scripting,
bindings from many languages.  http://libguestfs.org

On Thu, Jun 16, 2011 at 09:14:14PM +0530, (   [YeSwAnTh]   )-
wrote:
> 1)How do i handle .vdi images in guestfs.
We support whatever qemu supports.  It turns out that usually *.vdi
files "just work":

https://rwmj.wordpress.com/2010/10/04/tip-open-virtualbox-vdi-file-using-libguestfs/

If it doesn't work, then it's a qemu problem, so best to contact them.
(Or you could use another format like raw instead).
> the guestfs_add_drive_opts mentions only qcow2 and raw image
> formats.
You don't have to set the format parameter - it's optional.  If it's
not set, then qemu will autodetect it (as happens with 'add_drive').
Autodetection is unsafe if you don't trust your guests.

[test plan]
> What do you think of this?
Sounds perfectly reasonable.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
virt-top is 'top' for virtual machines.  Tiny program with many
powerful monitoring features, net stats, disk stats, logging, etc.
http://et.redhat.com/~rjones/virt-top