Saturday, July 2, 2011

Clone KVM with virt-clone

virt-clone is a command line tool for cloning existing virtual machine images using the "libvirt" hypervisor management library. It will copy the disk images of any existing virtual machine, and define a new guest with an identical virtual hardware configuration. Elements which require uniqueness will be updated to avoid a clash between old and new guests

virt-clone of python-virtinst package is a great tool for creating cloned KVM virtual machine quickly. 

Example:  LVM based kvm

# virt-clone --original sl6-3  \
             --name sl6-4 \
              --file /dev/mapper/vg_kvm-kvm6 --prompt

In the above example /dev/mapper/vg_kvm-kvm6 LVM should be created before executing the virt-clone command.

Creating LVM
# lvcreate -L 4G -n kvm6 vg_kvm

Example file based storage
virt-clone \
              --original ubuntu11 \
              --name ubuntu-2 \
              --file /var/lib/libvirt/images/ubuntu-2.img

--original sl6-3 = name of the existing KVM (make sure the original KVM is shutdown before creating clone out of it)

--name se6-4 = Name of the New KVM (cloned)
--file = In LVM case path to the existing storage, in file based storage the file will be automatically created by virt-clone

Troubleshooting Network issue
Upon booting the new cloned KVM VM I encounter with problem of not showing any network interface. After digging more it appears that udev on virtual machine changed the eth0 interface with eth1 due to change in MAC of the interface. Quick search on Google suggested the following solution to get back the 'eth0' interface on cloned vm.

1. Open /etc/sysconfig/network-scripts/ifcfg-eth0 and delete the following line and save the file


2. Remove the following filen and reboot the virtual machine


After reboot eth0 network interface will be available.


  1. Thanks for posting this, spent a while trying to track this down on my own before I found your blog.

  2. For the record: virt-sysprep of libguestfs can do required the /etc cleaning automatically:

  3. how did you get into your vm if the network was down? sorry, im new