Identify Backing Image for Instance (QEMU)

Problem

An instance, spawned on a KVM hypervisor leveraging QEMU virtualization, has an ephemeral disk which is typically backed by a base image in QCOW2 format. It may be necessary in some cases to verify the validity of the base image file. In order to do so, the file location of the backing image must be identified.

Environment

• Platform9 Managed OpenStack - All Versions
• KVM/QEMU

Procedure

1. Identify the following prior to any subsequent steps.
   • Instance UUID
   • Hypervisor/Host on which the instance resides.
   • File path of the instance storage for that particular hypervisor.
2. SSH to the instance's hypervisor.
3. Query the image information of the disk file associated with the instance.

xxxxxxxxxx

# qemu-img info [INSTANCE_STORAGE_PATH]/[INSTANCE_UUID]/disk

4. A backing file attribute is displayed with the path to the base image.Example:

xxxxxxxxxx

backing file: /opt/pf9/data/instances/_base/a788db23f9e99aed9431324a7c04bafe7c633604