Thank You for your reply.
What was the output of the 'virt-rescue --suggest -d XYZ'?
Inspecting the virtual machine or disk image ...
This disk contains one or more operating systems.  You can use these mount
commands in virt-rescue (at the ><rescue> prompt) to mount the filesystems.
# /dev/sda1 is the root of a linux operating system
# type: linux, distro: ubuntu, version: 12.4
# Ubuntu 12.04.3 LTS
mount /dev/sda1 /sysroot/
mount --bind /dev /sysroot/dev
mount --bind /dev/pts /sysroot/dev/pts
mount --bind /proc /sysroot/proc
mount --bind /sys /sysroot/sys
And did you run _all_ those commands? 
yes I run all those
commands in this sequence:
virt-rescue --network -d XYZ
mount /dev/sda1 /sysroot/
chroot /sysroot
update-initramfs -c -k 3.2.0-58-generic
But it failed with following error:
update-initramfs: failed for /boot/initrd.img-3.2.0-58-generic with 1.
Actually one of my VM in KVM platform got corrupted.When I try to start
it,I get the menu and after selecting Ubuntu, with Linux 3.2.0-58-generic
it gives an error "Kernel Panic - not Syncing: VFS: Unable to mount root fs
on unknown-block(0,0).So I thought of updating the initramfs to see if the
problem is resolved.But updation is failing.Your valuable suggestion is
awaited.
On Tue, Dec 2, 2014 at 11:05 PM, Richard W.M. Jones <rjones(a)redhat.com>
wrote:
 On Tue, Dec 02, 2014 at 02:26:49PM +0000, Suvajit Sarkar wrote:
 > Hello,
 > I am trying to run this command
 > virt-rescue --suggest -d XYZ
 > virt-rescue --network -d XYZ
 > the prompt is looking like this:
 > I have no name!@(none):
 This is probably:
 
https://bugzilla.redhat.com/show_bug.cgi?id=812970
 It is supposed to be fixed in libguestfs >= 1.28.
 > now I mounted the root partition suggested by virt-rescue to /sysroot
 > then chroot /sysroot
 > after that I tried to rebuild an initrd.img with the following command
 >
 > update-initramfs -c -k 3.2.0-58-generic
 >
 > But it failed with following error:
 > update-initramfs: failed for /boot/initrd.img-3.2.0-58-generic with 1.
 What was the output of the 'virt-rescue --suggest -d XYZ'?
 And did you run _all_ those commands?
 > Also when running  apt-get update , it fails saying "no address
 associated
 > with hostname.
 Likely you need to copy /etc/resolv.conf to /sysroot/etc/resolv.conf
 as well, so that name resolution works inside the chroot.
 > host configuration:ubuntu 14.04
 > guest:ubuntu 12.04
 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
 
-- 
Thanks and regards,
Suvajit Sarkar