> 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/unable-to-deauthorize-hypervisor-instances-still-exist.md).

# Unable to Deauthorize Hypervisor (Instances Still Exist)

## Problem

* When attempting to disable a host, you receive an error similar to the following.

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

```none
An unexpected error occurred trying to deauthorize host.
```

{% endtab %}
{% endtabs %}

* Instances in the Clarity UI which reside on the hypervisor in question at Infrastructure > Instances are not in a standard state such as "Error," "Deleting" or "Active - Rebooting".
* The same instances do not respond to **delete** commands from the Clarity UI, OpenStack CLI, nor OpenStack API.

## Environment

* Platform9 Managed OpenStack - All Versions
* Nova

## Cause

A host with the hypervisor role cannot be removed from the OpenStack cluster when it is still hosting instances, in any state.

## Resolution

1. Identify any remaining instances hosted on the hypervisor in question.

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

```none
$ openstack server list --all-projects --host [host_uuid]
```

{% endtab %}
{% endtabs %}

2. Issue the following commands to delete the remaining instances.

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

```none
# nova reset-state [instance_uuid] --active# openstack server delete [instance_uuid]
```

{% endtab %}
{% endtabs %}

3. Bring down the ***nova-compute*** service.

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

```none
# nova service-force-down [host_uuid] nova-compute+--------------------------------------+--------------+-------------+| Host                                | Binary      | Forced down |+--------------------------------------+--------------+-------------+| [host_uuid]                         | nova-compute | True        |+--------------------------------------+--------------+-------------+
```

{% endtab %}
{% endtabs %}

4. Verify the compute service has been brought down successfully.

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

```none
$ nova service-list | grep [host_uuid]| 123 | nova-compute    | [host_uuid]        | nova    | enabled  | down  | 2018-10-02T19:05:47.000000 | -                                  |
```

{% endtab %}
{% endtabs %}

5. At this point, you can complete the standard procedure for deauthorizing a host as described in [How To Deauthorize A Host](https://docs.platform9.com/openstack/infrastructure/deauth-host/).


---

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