• Symptom:
    When you start a VM instance, you may encounter the following similar errors:
    uses a qcow2 feature which is not supported by this qemu version: QCOW version 3
  • Cause:

    The main reason is that qcow versions are inconsistent. The original qcow2 uses the newer version of qemu-img, while the current qcow2 uses the older version of qemu-img. The older version of qemu-img is inconsistent with the newer version of qemu-img.

  • Solution:
    Perform compatibility transformation for the newer version of qemu-img. For example, run the following command to do the transformation. After transformation, add the image again.
    qemu-img convert -o compat=0.10 -f qcow2 -O qcow2 centos6-cloud-init.qcow2 centos-st-ssh-key.qcow2