The virt-v2v tool converts virtual machines from foreign hypervisors, including their disk images and metadata, for use with Red Hat Enterprise Linux KVM, Red Hat Enterprise Virtualization, and Red Hat Enterprise Linux OpenStack Platform.
This article provides instructions for converting and importing a Red Hat Enterprise Linux virtual machine from a Xen hypervisor to run on Red Hat Enterprise Linux 7 KVM.
For an overview of the virt-v2v tool, supported conversions, and links to other types of virtual machine conversions, see Converting Virtual Machines from Other Hypervisors to KVM with virt-v2v in RHEL 7.
Important: virt-v2v became a supported product starting with Red Hat Enterprise Linux 7.2. Therefore, we recommend you update your virt-v2v conversion server (the machine used to convert virtual machines) to Red Hat Enterprise Linux 7.2 before proceeding with the these instructions. Conversions may not work correctly on earlier versions of Red Hat Enterprise Linux.
To run a convert a guest virtual machine with virt-v2v, your system must have at minimum:
- Network bandwidth: minimum 1Gbps
- Disk space: sufficient space to store the guest as a file, plus 1 GB
- Sufficient free space in the guest filesystem according to the following table:
|File system||Minimum free space|
|Root file system||20 MB|
|Every other mountable file system||10 MB|
virt-v2v must be run on a Red Hat Enterprise Linux 64-bit host system. In addition to the standard virt-v2v package, you must install the libguestfs-winsupport and virtio-win packages and their dependencies:
# yum install virt-v2v libguestfs-winsupport virtio-win
In addition, it is necessary to do the following:
- Configure password-less SSH access to the remote Xen host from the virt-v2v conversion server.
# ssh-agent SSH_AUTH_SOCK=/tmp/ssh-36jmUA3rn2JS/agent.24318; export SSH_AUTH_SOCK; SSH_AGENT_PID=24319; export SSH_AGENT_PID; echo Agent pid 24319; # SSH_AUTH_SOCK=/tmp/ssh-36jmUA3rn2JS/agent.24318; export SSH_AUTH_SOCK; # SSH_AGENT_PID=24319; export SSH_AGENT_PID; # echo Agent pid 24319; Agent pid 24319 # ssh-add Identity added: /root/.ssh/id_rsa (/root/.ssh/id_rsa)
- Export the
LIBGUESTFS_BACKEND=directenvironment variable on the conversion server.
# export LIBGUESTFS_BACKEND=direct
- Add your SSH public key to the /root/.ssh/authorized_keys file on the Xen host.
# ssh-copy-id email@example.com /usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed /usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys firstname.lastname@example.org's password: Number of key(s) added: 1 Now try logging into the machine, with: "ssh 'email@example.com'" and check to make sure that only the key(s) you wanted were added.
- To test the SSH configuration:
# ssh firstname.lastname@example.org Last login: Tue Nov 1 14:39:21 2016 from ovpn-123-45.brq.redhat.com
The conversion server logs you in to the Xen host and does not request any password.
Ensure that the virtual machine is stopped prior to running the conversion process.
To convert a XEN Linux virtual machine:
# virt-v2v -ic 'xen+ssh://email@example.com' rhelx-y /v2vconvert/
where x-y is the version of Red Hat Enterprise Linux running on the virtual machine being converted. For example, for Red Hat Enterprise Linux 5.1, use
For a list of virt-v2v parameters, see the virt-v2v man page.
The following example shows the progress of virt-v2v converting a Red Hat Enterprise Linux 5 virtual machine running on a Xen host:
# virt-v2v -ic "xen+ssh://firstname.lastname@example.org" -os default rhel5-para [ 0.0] Opening the source -i libvirt -ic xen+ssh://root@xen-sample-host. com rhel5-para [ 0.0] Creating an overlay to protect the source from being modified [ 0.0] Opening the overlay [ 69.0] Initializing the target -o libvirt -os default [ 69.0] Inspecting the overlay [ 80.0] Checking for sufficient free disk space in the guest [ 80.0] Estimating space required on target for each disk [ 80.0] Converting Red Hat Enterprise Linux Server release 5.11 to run on KVM virt-v2v: This guest has virtio drivers installed. [ 136.0] Mapping filesystem data to avoid copying unused and blank areas [ 137.0] Closing the overlay [ 137.0] Checking if the guest needs BIOS or UEFI to boot [ 137.0] Copying disk 1/1 to /var/lib/libvirt/images/rhel5-para-sda (raw) (100.00/100%) [ 599.0] Creating output metadata Pool default refreshed Domain rhel5-para defined from /tmp/v2vlibvirt8e77ed.xml [ 599.0] Finishing off
On successful completion, virt-v2v creates a new libvirt domain XML file for the converted virtual machine with the same name as the original virtual machine. The virtual machine can be started using libvirt tools, such as virt-manager or virsh.
Confirm that the guest was imported correctly with the following command:
# virsh list --all
If this command lists the new Linux virtual machine, you have successfully converted and imported the guest. Boot the guest and confirm its full functionality before deleting the original guest or migrating active services.
- virt-v2v saves converted virtual machines to the current user's namespace. However, libvirt maintains separate namespaces for the virtual machines for each user. As a result, if virt-v2v is run as a non-root user, virt-manager will not see the converted virtual machine.
- It is currently not possible to convert guests from a Red Hat Enterprise Linux 5 Xen hypervisor, if the Xen server places the guests on block devices. (BZ# 1283588)
See the Red Hat Enterprise Linux 7 Virtualization Deployment and Administration Guide for more information on managing virtual machines with libvirt.
For more information on using virt-v2v to convert virtual machines, see the virt-v2v man page and http://libguestfs.org/virt-v2v.1.html.