Volumes are virtual hard drives which can be created and attached to instances

First create a volume in the Openstack Web Interface:

Next click the arrow on the volume then Manage Attachments:

Choose the instance you want to attach the volume to,  you do not need to set the device path.

SSH into the instance and use the command lsblk to show all of the volumes attached to the instance

Use the command   sudo mkfs.xfs -f <Device Path From lsblk> to format the newly attached volume.

In this example vdc is the new volume being attached, vdb is another volume already mounted and attached and vda is the OS's volume

Use the command    sudo mkdir <Volume Name>

Then sudo mount <Volume Path> <Volume Name>

You can see now the volume is mounted under /Volume1 and can be accessed