Ubuntu Pro is a service that provides additional benefits to individual Ceph nodes such as the Livepatch Service and, for LTS-based nodes, the Expanded Security Maintenance (ESM) program. Other add-ons are also available.
The service is free for limited personal usage, which includes both Livepatch and ESM. For commercial support, a subscription is needed.
Note: Ubuntu Pro is a separate, per-node, add-on service; it is not part of the Charmed Ceph project.