Skip to main content

​
Overview

Images obtained from VMware, VirtualBox, Hyper-V, or other virtualization platforms use formats that differ from what Xloud Compute expects. The qemu-img tool converts between all major disk image formats quickly and without data loss. QCOW2 is the recommended format for Xloud — it provides compression, snapshot support, and efficient sparse storage.
Prerequisites
  • A Linux workstation with qemu-utils installed
  • The source image file in its original format
  • Free disk space: RAW conversions require space equal to the full virtual disk size

​
Supported Formats

FormatExtensionDescriptionUse Case
QCOW2.qcow2Compressed, sparse, copy-on-writeRecommended for Xloud — best balance of size and performance
RAW.img, .rawUncompressed, full disk imageMaximum I/O performance; large file size
VMDK.vmdkVMware native formatImport from VMware ESXi or Workstation
VHD / VHDX.vhd, .vhdxHyper-V / Azure native formatImport from Hyper-V or Microsoft Azure
VDI.vdiVirtualBox native formatImport from Oracle VirtualBox
Converting to RAW format creates a file equal to the full virtual disk size, not just the used space. A 50 GB virtual disk produces a 50 GB RAW file even if only 5 GB is used. Ensure sufficient disk space before converting.

​
Install qemu-img

Install qemu-utils
apt-get update && apt-get install -y qemu-utils

​
Check Image Information

Before converting, inspect the source image to confirm its format, virtual size, and backing chain:
Inspect image metadata
qemu-img info source-image.vmdk
Expected output:
Example qemu-img info output
image: source-image.vmdk
file format: vmdk
virtual size: 20 GiB (21474836480 bytes)
disk size: 4.2 GiB
cluster_size: 65536
The disk size shows actual data written; virtual size shows the size instances see. QCOW2 preserves this sparse allocation — RAW expands to the full virtual size.

​
Common Conversions

Convert a VMware disk image to QCOW2:

Convert the image

Convert VMDK to QCOW2
qemu-img convert \
  -f vmdk \
  -O qcow2 \
  source-image.vmdk \
  output-image.qcow2
The -f flag specifies the source format; -O specifies the output format.

Verify the output

Verify converted image
qemu-img info output-image.qcow2
Output shows file format: qcow2 and virtual size matches the source.

​
Validation

After conversion, perform a consistency check before uploading to Xloud:
Check image integrity
qemu-img check output-image.qcow2
Expected output:
Clean image output
No errors were found on the image.
If qemu-img check reports errors, the conversion may have encountered a corrupt source image. Re-obtain the source and retry the conversion. Do not upload a corrupted image — instances launched from it will fail unpredictably.

​
Next Steps

Upload an Image

Upload the converted QCOW2 image to the Xloud Image Service.

Image Requirements

Verify the image meets all Xloud Compute compatibility requirements.

Modify Images

Customize images with additional packages and configuration before uploading.

Image Formats

Compare all supported image formats and choose the right one for your workload.