# 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.

{% tabs %}
{% tab title="None" %}

```none
# qemu-img info [INSTANCE_STORAGE_PATH]/[INSTANCE_UUID]/disk
```

{% endtab %}
{% endtabs %}

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

{% tabs %}
{% tab title="None" %}

```none
backing file: /opt/pf9/data/instances/_base/a788db23f9e99aed9431324a7c04bafe7c633604
```

{% endtab %}
{% endtabs %}


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