Kubevirt中用ContainerDisk创建VMI比PVC多一个容器是否正常？

Absolutely, this is completely normal behavior when using ContainerDisk with KubeVirt—let me break down why you see this difference:

• How ContainerDisk works: A ContainerDisk packages your VM disk image (like a qcow2 file) into a standard Docker container image. When KubeVirt spins up the VMI, it can't directly use the container image as a VM disk. Instead, it creates an auxiliary container (the volumecontainervolume one you see) whose sole job is to mount the ContainerDisk image, extract the underlying VM disk file, and expose it to the main compute container (which runs the actual VM). This auxiliary container acts as a bridge between the container registry-hosted image and the VM runtime.

• Why PVC doesn't need this extra container: When using a PVC (backed by a disk uploaded via CDI), the VM disk is already stored as a persistent volume that can be directly mounted by the compute container. There's no need to unpack or extract a container image first—KubeVirt can attach the PVC volume directly to the VM runtime container, so only one container is needed in the Pod.

If you want to confirm this, run kubectl describe pod virt-launcher-centos-5kfvw and look at the volume mounts for the volumecontainervolume container. You'll see it's mounting the ContainerDisk image and sharing its content with the compute container via an emptyDir volume. This container stays running for the lifetime of the Pod, but it's just a lightweight helper with minimal resource usage.

内容的提问来源于stack exchange，提问作者Munna