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:

Snapshot the volume.
Create a new volume from the snapshot.
(optionally) Delete the original instance with its volume.

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).