--- title: "How to start a Public Cloud instance on a bootable volume" description: "Learn how to start an instance on an attached volume." url: https://docs.us.ovhcloud.com/en/public-cloud/compute/start-instance-on-attached-volume lang: en --- > For AI agents: the complete documentation index is available at https://docs.us.ovhcloud.com/en/llms.txt, the full documentation bundle is available at https://docs.us.ovhcloud.com/en/llms-full.txt. # How to start a Public Cloud instance on a bootable volume **Learn how to start an instance on an attached volume.** Public Cloud instances come with an original disk that is copied from a system image (Debian 12, Windows Server, etc.). It is also possible to use additional volumes, which are persistent disks that will allow data to be stored. You can also deploy an operating system to and from a volume. The Public Cloud instance will then start on this volume instead of the original disk. **Tip:** OpenStack natively allows you to boot from a volume. It involves making the volume bootable and starting the instance from this volume. The changes will cause the original disk to be replaced by the new volume. The functionality described in this guide eliminates the need to access the original disk and, therefore, takes advantage of the volume. **Warning:** **NOTE**: With the current version of OpenStack, rescue-pro mode is not available on an instance booted via a bootable volume.   ## Requirements - [Access to the Horizon interface](https://docs.us.ovhcloud.com/en/public-cloud/cross-functional/introducing-horizon.md) - [Setting OpenStack environment variables](https://docs.us.ovhcloud.com/en/public-cloud/cross-functional/compute-set-openstack-environment-variables.md)   ## Instructions ### Creating a bootable volume from an image #### Horizon Log in to the [Horizon interface](https://horizon.cloud.ovh.us/auth/login/). Select the appropriate region from the drop-down menu at the top left. On the Project tab, open the `Volumes` section and click the `Volumes` dashboard. Click on `Create Volume`. In the dialog box that opens, enter or select the following values: - **Volume Name** - **Description** (optional) - **Volume Source:** Image - **Use image as a source** - **Type** - **Size (GB)** - **Availability Zone:** nova Click on `Create Volume`. The volume will be in a `creating` state then a `downloading` state before being available. If you click the volume name, you will see the volume's details and that the **Bootable** line says `Yes`. #### OpenStack client You can create a bootable volume from an existing image, volume, or volume snapshot. This procedure shows you how to create a volume from an image and use the volume to boot an instance. ```console $ openstack image list ``` **Note:** Note the ID or the name of the image that you wish to use. Create a bootable 10GB high-speed volume named **volume\_ubuntu** from an Ubuntu 24.04 image: You can install an image on a volume using the `--image` argument: ```console $ openstack volume create --type high-speed --image 2c2e28dc-9124-49c3-b92d-7f00bd83ac86 --size 10 volume_ubuntu +---------------------+--------------------------------------+ | Field | Value | +---------------------+--------------------------------------+ | attachments | [] | | availability_zone | nova | | bootable | false | | consistencygroup_id | None | | created_at | 2025-02-06T17:04:34.000000 | | description | None | | encrypted | False | | id | d7611318-fd7b-4b6a-8a7a-8d368049f747 | | multiattach | False | | name | volume_ubuntu | | properties | | | replication_status | None | | size | 20 | | snapshot_id | None | | source_volid | None | | status | creating | | type | high-speed | | updated_at | None | | user_id | 1a67934f87ef481d9cb617a913bfa8bb | +---------------------+--------------------------------------+ ``` In this command, **2c2e28dc-9124-49c3-b92d-7f00bd83ac86** is the Ubuntu 24.04 image ID. **Note:** Cinder makes a volume bootable when the `--image` parameter is passed.   ### Starting an instance using a bootable volume #### Horizon Log in to the [Horizon interface](https://horizon.cloud.ovh.us/auth/login/). Select the appropriate region from the drop-down menu at the top left. On the Project tab, open the `Compute` section and choose `Instances`. Click on `Launch Instance`. In the `Launch Instance` dialog box, enter the information requested. Refer to the guide [Create an instance from the Horizon interface](https://docs.us.ovhcloud.com/en/public-cloud/compute/create-instance-in-horizon.md) for more details. In the Source tab, choose `Volume` in the **Select Boot Source** field. A new field for volume selection appears. You can select the previously created volume from the list. Make your selections in the **Details**, **Flavor**, and **Networks** areas. Click on `Launch Instance`. The instance will be in a `build` state then `Block Device Mapping` state before being available. The instance will eventually have the volume attached. #### OpenStack client Create an instance, specifying the bootable volume **volume\_ubuntu** as the boot device. ```console openstack server create --volume volume_ubuntu --flavor d2-2 --key-name publickey --nic net-id=Ext-Net InstanceTest ``` List the volumes to ensure the status has changed to in-use and the volume is correctly reporting the attachment: ```console $ openstack volume list +--------------------------------------+---------------+--------+------+--------------------------------------+ | ID | Name | Status | Size | Attached to | +--------------------------------------+---------------+--------+------+--------------------------------------+ | d7611318-fd7b-4b6a-8a7a-8d368049f747 | volume_ubuntu | in-use | 10 | Attached to InstanceTest on /dev/sda | +--------------------------------------+---------------+--------+------+--------------------------------------+ ``` List the volumes attached to the **InstanceTest** Instance: ```console $ openstack server volume list InstanceTest +--------------------------------------+----------+--------------------------------------+--------------------------------------+------+ | ID | Device | Server ID | Volume ID | Tag | +--------------------------------------+----------+--------------------------------------+--------------------------------------+------+ | d7611318-fd7b-4b6a-8a7a-8d368049f747 | /dev/sda | 5d97c190-f2e3-4af4-a010-6fa7bffbf88b | d7611318-fd7b-4b6a-8a7a-8d368049f747 | None | +--------------------------------------+----------+--------------------------------------+--------------------------------------+------+ ``` **Note:** You can also create an instance, using the chosen image and requesting "boot from volume" behavior. ```console $ openstack server create --flavor d2-2 --key-name publickey --nic net-id=Ext-Net --image b680f0aa-8eb8-4ac8-b008-2a90bb71af4f --boot-from-volume 10 InstanceTest2 +-----------------------------+---------------------------------------------+ | Field | Value | +-----------------------------+---------------------------------------------+ | OS-DCF:diskConfig | MANUAL | | OS-EXT-AZ:availability_zone | | | OS-EXT-STS:power_state | NOSTATE | | OS-EXT-STS:task_state | scheduling | | OS-EXT-STS:vm_state | building | | OS-SRV-USG:launched_at | None | | OS-SRV-USG:terminated_at | None | | accessIPv4 | | | accessIPv6 | | | addresses | | | adminPass | dP4e4iY3eWWC | | config_drive | | | created | 2025-02-06T17:20:06Z | | flavor | d2-2 (dc3fe9e7-e374-4ad8-b200-fa3bdf45069f) | | hostId | | | id | a4632249-e1b4-4047-be1c-87f8b0328f7c | | image | N/A (booted from volume) | | key_name | publickey | | name | InstanceTest2 | | progress | 0 | | project_id | d7fb756ae2c24b1cb8630ec7f56ee4a8 | | properties | | | security_groups | name='default' | | status | BUILD | | updated | 2025-02-06T17:20:06Z | | user_id | 1a67934f87ef481d9cb617a913bfa8bb | | volumes_attached | | +-----------------------------+---------------------------------------------+ ``` In the command above, `b680f0aa-8eb8-4ac8-b008-2a90bb71af4f` is the Debian 12 image ID. - List the volumes: List the volumes to ensure the status has changed to in-use and the volume is correctly reporting the attachment. ```console $ openstack volume list +--------------------------------------+---------------+--------+------+----------------------------------------+ | ID | Name | Status | Size | Attached to | +--------------------------------------+---------------+--------+------+----------------------------------------+ | 27f8332d-8bfd-4515-b0a8-18667ae50ff8 | | in-use | 10 | Attached to InstanceTest2 on /dev/sda | | d7611318-fd7b-4b6a-8a7a-8d368049f747 | volume_ubuntu | in-use | 10 | Attached to InstanceTest on /dev/sda | +--------------------------------------+---------------+--------+------+----------------------------------------+ ``` List the volume on the server to make sure it's properly attached. ```console $ openstack server volume list InstanceTest2 +--------------------------------------+----------+--------------------------------------+--------------------------------------+------+ | ID | Device | Server ID | Volume ID | Tag | +--------------------------------------+----------+--------------------------------------+--------------------------------------+------+ | d7611318-fd7b-4b6a-8a7a-8d368049f747 | /dev/sda | 5d97c190-f2e3-4af4-a010-6fa7bffbf88b | d7611318-fd7b-4b6a-8a7a-8d368049f747 | None | +--------------------------------------+----------+--------------------------------------+--------------------------------------+------+ ```   ## Go further Browse all the [Compute guides](https://docs.us.ovhcloud.com/en/public-cloud/compute/landing-page-compute.md). Browse the rest of the [OVHcloud US documentation](https://docs.us.ovhcloud.com/en/index.md) for guides on our other products and services. Learn more about [Public Cloud Compute](https://us.ovhcloud.com/public-cloud/compute/) on the OVHcloud US website.