Need explanation on how to setup Ceph Storage Node journals partitions using GPT labels

Issue

• When following the documentation for deployment including Ceph
  ,We see that it's necessary to configure/partition the Ceph OSD disks before installing them with Openstack.
• How can we use ironic/the undercloud to perform disk partition configuration on new Ceph nodes? We do not want to manually configure dozens of machines/partitions.
• How can the undercloud be configured to deploy something like the discovery image but with the sole purpose of configuring a machine's disks?