> 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/how-to/vm-migration-fails-with-guest-cpu-doesn-t-match-specification.md).

# VM migration fails with 'guest CPU doesn't match specification: missing features: md-clear' error.

## Problem

* VM migration fails with 'guest CPU doesn't match specification: missing features: md-clear' error.
* It looks like migration is failing because destination host is missing one of the CPU flag `md-clear:`

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

```javascript
2022-08-29 13:26:31.610 ERROR nova.virt.libvirt.driver [-] [instance: fff634fgh-b284-2048-a284-545c7a5b7876] Live Migration failure: operation failed: guest CPU doesn't match sp
ecification: missing features: md-clear: libvirt.libvirtError: operation failed: guest CPU doesn't match specification: missing features: md-clear
2022-08-29 13:26:32.241 INFO nova.virt.libvirt.driver [-] [instance: fff634fgh-b284-2048-a284-545c7a5b7876] Migration running for 0 secs, memory 100% remaining (bytes processed=0, remaining=0, total=0); disk 100% remaining (bytes processed=0, remaining=0, total=0).
```

{% endtab %}
{% endtabs %}

## Environment

* Platform9 Managed OpenStack - v5.4.0 and higher

## Cause

* The instance is being migrated to a destination host that does not have the required CPU flag.

## Resolution

* Update the destination host's kernel to have the required CPU flag.


---

# 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 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/how-to/vm-migration-fails-with-guest-cpu-doesn-t-match-specification.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 `automate deployments from our CI pipeline` 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.