How to clone a libvirt VM controlled by Vagrant

Strangely enough, googling about this problem doesn’t produce any meaningful results. So here are steps which allow cloning a libvirt VM controlled by Vagrant. Imagine that you have a VM named testvm1 which you want to clone into testvm2.

Shutdown all VMs with vagrant halt or at least from inside of VM with sudo shutdown -h 0.
Figure our real VM name with virsh list --all | grep testvm1. Usually Vagrant adds its own vagrant_ prefix to VM names. If you don’t like it, you can rename VM with virsh domrename command, Vagrant will still know it because Vagrant refers to VMs by UUID instead of a name.
Clone VM image with virt-clone --original testvm1 --name testvm2 --auto-clone. You can specify additinal options like new image file name instead of --auto-clone.
Edit your Vagrantfile to produce a configuration for new testvm2 VM. I have an array of VM names which I loop over like this:
```
  names_array = ['testvm1', 'testvm2']
# .....
  (0..vm_total_number - 1).each do |i|
    vm_name = names_array[i]
    config.vm.define "#{vm_name}" do |node|
      node.vm.hostname = "#{vm_name}"
# .......
    end
  end
```
1. Find new VM UUID with virsh dumpxml testvm2 | grep uuid.
2. Copy directory .vagrant/machines/testvm1 to.vagrant/machines/testvm2.
3. Edit file .vagrant/machines/testvm2/libvirt/id and put new UUID there.
4. Edit file .vagrant/machines/testvm2/libvirt/action_provision and replace old UUID with new one there as well.
5. Create a new 32-digital HEX identifier, e.g. with dd count=1 if=/dev/random 2> /dev/null | md5sum.
6. Write this ideintfier to file index_uuid instead of an old one.
7. Edit file ~/.vagrant.d/data/machine-index/index. It is in JSON format. You need to copy a block beginning with an old contents of index_uuid and all that follows it in curly brackets {}. Be careful and make a file backup because it is very easy to break JSON syntax. Now in new VM block change the VM id to newly generated and change its host name for "name": tag.
8. Check with vagrant status that you have a new VM in shutdown state.
9. You are ready to start a VM with vagrant up command.

August 30, 2018

How to clone a libvirt VM controlled by Vagrant