> 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/boot-from-volume-instance-fails-to-spawn-block-device-mapping-i.md).

# Boot From Volume Instance Fails to Spawn: "Block Device Mapping is Invalid

## Problem

* A volume-backed instance creation fails with the following error: **"** Block Device Mapping is Invalid *".*
* The same error is observed in */var/log/pf9/ostackhost.log* on the destination host.

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

```none
ERROR nova.compute.manager Attaching block device to instance [UUID] failed. Error: Volume [UUID] did not finish being created even after we waited 193 seconds or 61 attempts. And its status is creating.
```

{% endtab %}
{% endtabs %}

## Environment

* Platform9 Managed OpenStack - v3.6.0 and Higher
* Glance
* Nova

## Cause

The image specified for the volume is taking too long to be downloaded from the Image Library (Glance) host(s) to the destination hypervisor and subsequently uploaded to the Block Storage (Cinder) backend. The time it takes for the image to be downloaded depends on many factors including the raw image size and network latency amongst the hosts.

## Resolution

1. SSH to the host.
2. Edit the *nova\_override.conf* file. (Create the file if it does not already exist.)

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

```none
$ vi /opt/pf9/etc/nova/conf.d/nova_override.conf
```

{% endtab %}
{% endtabs %}

3. Identify the following parameters:

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

```none
[DEFAULT]
block_device_allocate_retries
block_device_allocate_retries_interval
```

{% endtab %}
{% endtabs %}

If the above options are not present, the default values would be used which are:

```
block_device_allocate_retries = 60
```

`block_device_allocate_retries_interval = 3`

4. You can double the values to ensure that Nova makes 120 attempts and waits for 6 seconds between each attempt.
5. Restart the ***pf9-ostackhost*** service

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

```none
# service pf9-ostackhost.service restart
```

{% endtab %}
{% endtabs %}

## Additional Information

[OpenStack Docs - Nova Configuration Options](https://docs.openstack.org/newton/config-reference/compute/config-options.html)


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