> For the complete documentation index, see [llms.txt](https://docs.platform9.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.platform9.com/managed-openstack/volumes-and-snapshots/storage-cinder-metadata.md).

# Understanding Cinder Metadata

When you attach a volume to an instance, Cinder automatically adds the `attached_mode` and `readonly` key-value pairs to the volume. These tags describe the state of the volume and are not directly modifiable by the user.

The `attached_mode` key describes whether the volume is read-only or read-writable and appears only when the volume is attached.

The `readonly` key describes whether the volume can be attached as read-only or read-writeable .

Cinder automatically removes the `attached_mode` key when the volume is detached from an instance. However, the `readonly` key stays indefinitely.

To attach a volume as read-only, set the read-only mode to `true` using the Cinder client:

{% tabs %}
{% tab title="Bash" %}

```bash
cinder readonly-mode-update true
```

{% endtab %}
{% endtabs %}

To attach as volume as read-writeable, set the read-only mode to `false`:

{% tabs %}
{% tab title="Bash" %}

```bash
cinder readonly-mode-update false
```

{% endtab %}
{% endtabs %}


---

# 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 current page URL with the `ask` query parameter:

```
GET https://docs.platform9.com/managed-openstack/volumes-and-snapshots/storage-cinder-metadata.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
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.