Using virsh to add a volume (disk) to an existing vm

I have a second hard disk mounted under /thepool, and I want to make “virtual disks” in there and be able to mount them on any of my virsh-defined virtual machines.

The root filesystem of the VM resides on a different storage pool (uvtool) on a fast SSD, but for bulk storage I don’t want to fill out the SSD with crap.

# Create the storage pool, under "/thepool" where the big disk is mounted
virsh pool-define-as disk-pool dir - - - - "/thepool/libvirt-pool/"
virsh pool-build disk-pool
virsh pool-autostart disk-pool
virsh pool-start disk-pool
# CHeck it's there
virsh pool-list
# Create a volume inside the pool, qcow2 format
virsh vol-create-as disk-pool juju-zfs-pool.qcow2 64G --format qcow2
# Attach it to the VM
virsh attach-disk juju /thepool/libvirt-pool/juju-zfs-pool.qcow2  vdc --persistent  --subdriver=qcow2
# Now inside the vm, /dev/vdc exists and can be formatted/partitioned and mounted as normal