# Instance Failed To Start When Multipath Volume is Attached

## Problem

VM is failing to start when multipath volumes are attached to the VM and `ostackhost` shows below error logs:

{% tabs %}
{% tab title="ostackhost logs" %}

```yaml
ERROR oslo_messaging.rpc.server [req-ID] Exception during message handling: oslo_concurrency.processutils.ProcessExecutionError: Unexpected error while running command.
Command: multipath -f <multipath_ID>
Exit code: 1
Stdout: 'Apr 09 04:25:29 | <multipath_ID>-part7: map in use<br>Apr 09 04:25:29 | failed to remove multipath map <multipath_ID><br>'
Stderr: ''
TRACE oslo_messaging.rpc.server Traceback (most recent call last):
TRACE oslo_messaging.rpc.server   File "/opt/pf9/venv/lib/python3.6/site-packages/oslo_messaging/rpc/server.py", line 166, in _process_incoming
TRACE oslo_messaging.rpc.server     res = self.dispatcher.dispatch(message)
TRACE oslo_messaging.rpc.server   File "/opt/pf9/venv/lib/python3.6/site-packages/oslo_messaging/rpc/dispatcher.py", line 265, in dispatch
TRACE oslo_messaging.rpc.server     return self._do_dispatch(endpoint, method, ctxt, args)
```

{% endtab %}
{% endtabs %}

## Environment

* Platform9 Managed OpenStack - v5.1 and Higher
* Multi-path Volumes

## Cause

The hosts is failing to flush the multipath map and creating stale entries.

## Resolution

* Login to the host where the VM is running and list the paths to the LUN and volumes

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

```yaml
# multipath -ll   <multipath_ID>
# lsblk /dev/dm-<DM_ID>
```

{% endtab %}
{% endtabs %}

* Remove the volume entries

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

```yaml
# dmsetup remove <volume-entries>
```

{% endtab %}
{% endtabs %}

* Remove the named multipath device.

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

```yaml
# multipath -f /dev/disk/by-id/dm-uuid-mpath-<ID>
```

{% endtab %}
{% endtabs %}

* Now start the stop the server and start it again

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

```yaml
# openstack server stop <UUID>
# openstack server start <UUID>
```

{% endtab %}
{% endtabs %}


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