Convert VMDK or VHDX to qcow2 for KVM

Moving a VM from VMware, VirtualBox or Hyper-V to KVM usually comes down to converting its disk. qemu-img reads all the common formats, so you can convert VMDK or VHDX to qcow2 and boot the same system on KVM or Proxmox VE.

Before you start

A KVM host with qemu-img and virt-install; see install KVM on Ubuntu.
The source VM shut down cleanly (not suspended) and any snapshots consolidated.
Free disk space for the converted image, at least the source's used size.
A backup of the original VM.

Prepare the source VM

Linux guests: make sure VirtIO modules are in the initramfs (most modern distributions include them).
Windows guests: install the virtio-win drivers before migrating, or plan to boot with an emulated SATA disk first. See VirtIO drivers.
Uninstall VMware Tools or Hyper-V-specific agents if possible.

Export the disk

Source	Disk format	Where to find it
VMware ESXi / Workstation	VMDK	Datastore browser or VM folder (copy the descriptor and `-flat.vmdk`)
VirtualBox	VDI or VMDK	VM folder under VirtualBox VMs
Hyper-V	VHDX or VHD	Hyper-V virtual hard disks folder

Copy it to the KVM host with scp or rsync.

Convert the disk to qcow2

qemu-img convert -p -f vmdk -O qcow2 web01.vmdk /var/lib/libvirt/images/web01.qcow2

For other formats change -f: vdi, vhdx or vpc (for legacy VHD). Inspect the result:

qemu-img info /var/lib/libvirt/images/web01.qcow2

Import the VM

virt-install --name web01 --memory 4096 --vcpus 2 --disk /var/lib/libvirt/images/web01.qcow2,bus=virtio --import --os-variant ubuntu22.04 --network bridge=br0,model=virtio --graphics vnc,listen=127.0.0.1 --noautoconsole

If the source used UEFI, add --boot uefi.
For Windows without VirtIO drivers yet, use bus=sata and model=e1000e first.

Proxmox users can run qm importdisk or use the ESXi import wizard in recent versions.

Fix things after first boot

Network interface renamed (e.g. ens160 becomes enp1s0): update Netplan or NetworkManager config. See static IP with Netplan.
Windows: install virtio-win guest tools, then switch disk and NIC to VirtIO.
Install qemu-guest-agent.

Troubleshooting

"No bootable device": BIOS/UEFI mismatch; match the source's firmware.
Linux drops to emergency shell: missing VirtIO drivers in initramfs or fstab using old device names; boot with SATA, rebuild initramfs, use UUIDs.
Windows INACCESSIBLE_BOOT_DEVICE: no storage driver for the new controller; boot with SATA first.

Frequently asked questions

Can I convert while the VM runs?

Not safely. Convert from a clean shutdown or an exported snapshot.

Should I convert to raw instead?

Use -O raw if you will place the disk on LVM or ZFS. See qcow2 vs raw.

Does virt-v2v help?

Yes. virt-v2v automates conversion and driver injection, especially for VMware and Windows sources.

Next steps

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