Detach a volume

If you want to save a volume (when deleting the instance) for later or just remove it from an instance, you must first detach it. This means “un-hook it” from the instance so that its no longer usable. A boot disk (that is, the disk that stores the instances operating system) cannot be detached. If you want to save such a volume, the workflow would be:

Because of this, volumes that are non-detachable (for being boot drives) will not give that option in the cloud management portal - and will produce an error when trying to detach in OpenStack Horizon or via the OpenStack terminal client.

Important

While its possible, we don’t recommend detaching a volume on a running VM as it could impact the data integrity if its not properly unmounted.

Cloud management portal

To detach a volume using the Cloud management portal, follow these steps:

  • Press “Compute” and then “Instances” in the sidebar menu.

  • Press the instance that you want to resize.

  • Press the “Volumes” tab.

  • Press the small chain-link icon with a line over to the right next to the volume you want to remove. If there isn’t such an icon, then the volume cannot be removed.

OpenStack Horizon

To detach a volume using OpenStack Horizon, follow these steps:

  • Under “project”, click “compute” and then “instances” in the sidebar menu.

  • Press the name of the instance from which you want to remove a volume.

  • At the bottom, under the “volumes attached” section, press the volume you want to detach.

  • At the top right, press the dropdown and select “Manage Attachments”.

  • Press “Detach volume” on the row of the instance.

  • If you get an error, most likely the volume is a boot volume and cannot be detached (see above).

OpenStack Terminal Client

To detach a volume using the OpenStack terminal client, follow these steps:

  • Run this command: openstack server list, save the name of the instance to which the volume you want to extend is connected.

  • Run this command: openstack server volume list [NAME_OF_INSTANCE], replacing the name with that from previous step.

  • Run this command: openstack server remove volume [INSTANCE_ID] [VOLUME_ID], replacing the items in angle brackets with the “Server ID” and “Volume ID” from the output of the previous command.

  • If you get an error, most likely the volume is a boot volume and cannot be detached (see above).