> For the complete documentation index, see [llms.txt](https://platform9.com/kb/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://platform9.com/kb/pmo/solution/instance-creation-failing-could-not-open-backing-file.md).

# Instance Creation Failing: "Could not open backing file"

## Problem

* Instance creation is failing with the following error.

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

```none
Could not open backing file: Could not open '/opt/pf9/data/instances/_base/[UUID]': Permission denied
```

{% endtab %}
{% endtabs %}

* AppArmor is installed/enabled on the hypervisor.

## Environment

* Platform9 Managed OpenStack - All Versions
* Nova
* Libvirt
* AppArmor

## Cause

The default AppArmor profile for Libvirt does not include access to the instance storage path; thus, the I/O request is blocked.

## Resolution

1. Append the following lines to the AppArmor configuration at `/etc/apparmor.d/usr.lib.libvirt.virt-aa-helper`.

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

```none
/opt/pf9/data/instances/_base/** r,  /opt/pf9/data/instances/** rw,
```

{% endtab %}
{% endtabs %}

2. Parse the updated rules.

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

```none
# apparmor_parser -r /etc/apparmor.d/usr.lib.libvirt.virt-aa-helper
```

{% endtab %}
{% endtabs %}

## Additional Information

[Debian – #892431 AppArmor denies access for libvirt to nova instances directory](https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=892431)


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters:

```
GET https://platform9.com/kb/pmo/solution/instance-creation-failing-could-not-open-backing-file.md?ask=<question>&goal=<user_goal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `build a script that syncs our docs to a CMS` lets GitBook tailor the answer to that use case.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.