We saw volume creation with related issues and probable solutions.
Now we will see volume attach to VM. Create partition on it. Remove it and detach volume from VM.
Attach created volume to testvm. Following is command-line requirement for cinder volume-attach.
Volume ID will get it from cinder-list use auto to autoassign the new device.
You can check volume status is changed to in-use now and also changed attached with VM ID.